Continuing Comments on Randomness and Naturalism

Direct Continuation of: A portion of the comments section of “The Twelve Reasons I Don’t Believe in Supernatural Claims, Part I”

Follow up to: Proving God Through Cosmology?

For the past couple of weeks, three people — Bryan White of the blog Sublime Bloviations, Joseph, and myself — have had quite an involved conversation in the comment fields of my essay “The Twelve Reasons I Don’t Believe in Supernatural Claims, Part I” (conversation started here) about my definition of naturalism, the metaphysical and physical implications of quantum mechanics, uncaused influences, and just general randomness on that definition.

As a general summary, Brian was arguing that the existence of uncaused influences and quantum randomness meant that events existed which do not require an underlying mechanism, meaning my notion of naturalism is wrong and/or incomplete. I am attempting to get to the bottom of this, mostly by arguing against — that there is insufficient reason to think my naturalism is in error. Joseph was probing both of us with questions to sort out more of what is going on.

Already, the essay there ballooned to 79 comments, definitely an unprecedented level for my site. Unfortunately, since I was away from my blog for a week, I had not yet written a response. I now notice that my response is very lengthy, hence I felt it was better suited as a full essay, rather than as a series of comments.

I also noticed that taking to an essay to respond to these comments allowed me to (1) re-examine the issues raised in greater depth than I otherwise would of, and (2) spin-off the comments that were getting increasingly less relevant to the topic of the original essay and more deserving of a topic of their own.

So I will now be responding to all the comments that need responding here, plus providing a lot of background information so that additional readers can get involved in the commentary and weigh in their own opinion. I will invite the topic to continue here from now-on, with a reminder that everyone who wants to get seriously involved is suggested to read all the previous and relevant commentary on the original essay.

Also, as a warning to all parties — involved, interested, or already bored — this essay is going to be long. As a second warning, this post will involve the analysis of physics that goes far beyond my professional expertise, or the expertise of any of the involved commenters. None of us have any credentials in physics, a field widely acknowledged as one you cannot understand simply by reading a few Wikipedia articles.

Click to enlarge

The Definition of Naturalism, Take Four

Me: I’m still interested in what you think a suitable definition of naturalism or supernaturalism would be.

Bryan White: I think the traditional definition (the one you’ll see in dictionaries and encyclopedias) is fine.

I don’t think that works upon further examination, though. Let’s use the one from Wikipedia: “Naturalism commonly refers to the philosophical viewpoint that the natural universe and its natural laws and forces (as opposed to supernatural ones) operate in the universe, and that nothing exists beyond the natural universe or, if it does, it does not affect the natural universe that we know.”

But this requires us to ask what is a “natural universe” — what, specifically are we excluding? what are supernatural laws and forces, as opposed to natural ones?

The supernatural seems like a combination of Platonic ideals + miracles + angels + souls + Gods. And all of these things involve that which cannot be reduced to atoms; instead being fundamentally conceptual and ontologically separate. I think it would be fair to describe my position as saying everything is fully reducible to atoms acting in lawful manners. This excludes the entire gamut I just mentioned… except you probably could construct reducible versions of the supernatural. (I would call those natural and view them as not excluded by naturalism, though presently paranormal and excluded by the lack of evidence in their favor.)

But there are two important qualifications I want to make:

The first is that I expect atoms and laws to be even further reduced. I don’t predict the destination, and just as I don’t think naturalism was overthrown when we learned about the electron; I don’t think that further reduction will mean I was wrong now. I believe this was Andrew Melnyk’s dilemma, which I mentioned in “The Metaphysics Dilemma”.

The second is what I view to be the supremacy of epistemological naturalism over metaphysical naturalism. Epistemological naturalism is the idea that “metaphysical naturalism is true because all other ideas proposed so far are incoherent.” I don’t foresee the responsibility of predicting where naturalism will end up as the responsibility of naturalists. We can just chalk that up to not having all the answers yet, and wait for answers from continuing work in physics.

What’s important to me is specifically why we’re excluding the supernatural, which is the basis for epistemological naturalism that I talked about in “The Metaphysics Dilemma”, and which I’ll talk about further down in this essay. Thus I see that starting with the standard dictionary definition and resolving the ambiguities, you actually arrive at the definition I use. You’ll probably see this as spinning my wheels a bit, but this becomes important later on in my response.

What About the Supernatural?

Bryan: And I don’t ordinarily find “supernatural” a useful term. In my discussions with atheists it seems to mean something like “things that don’t happen” or the like. It doesn’t make for productive discussions. So I take the approach of letting you define “naturalism” and then seeing if there are logical possibilities and/or observed phenomena for which we need a term other than “natural.”

I agree, and think that is a great approach. But it seems like you keep trying to say I’m not excluding enough with my worldview, which is why I wonder what you think I ought to be excluding in order to be consistent, and what makes you think I should be excluding that.

What About Harry Potter?

If you think about it, what people ordinarily describe as “magic” is perfectly natural according to your descriptions. The potions from Hogwarts are akin to chemical formulas and act in predictable (causal) ways when prepared properly. Does Harry Potter use supernatural arts? Or no?

The problem with this example is the distinction I keep trying to make by the actual event and the explanation given for the event. Observing say, the actions of a polyjuice potion, is clearly paranormal in the extreme — radically outside the currently known science as applied to potions.

But there are ways we could consider it accomplished “naturally”, say by a complete atom-by-atom rearrangement and replacement (similar to the responses Joseph gave about stick-to-snake things). Saying “Magic!” doesn’t help us at all to explain how the transformation takes place — and this is what I seek to rule out with epistemic naturalism. This is the whole “Making the Question Go Away” theme that I think makes epistemic naturalism so obviously correct to me.

So, if I were to observe a potion like this take place, would I assume it was “magic”? Well, I couldn’t even say so, because the word “magic” entails nothing I can evaluate — and I don’t even mean that with some sort of testable/untestable paradigm. It is a non-starter because it’s incoherent — it’s like asking me if what I saw was “fhwgwgd”. Well, tell me what “fhwgwgd” describes and then I’ll tell you if what I saw was “fhwgwgd”. I can’t know until I know what “fhwgwgd” means.

Harry Potter and Imagining Incoherent Things

A very similar idea is that we can actually imagine some logically impossible and completely incoherent events. Sure, you can never imagine a square circle, but imagine looking at a sheet of paper with six different numbers. Now, notice that every time you add up the numbers in one direction, they sum up to 47, and every time you add up the numbers in the other direction, they sum up to 49. You could never imagine any reason why this is so, but you can imagine the experience of seeing it. And you can imagine doing all sorts of things to make the chance of it being a really odd counting error less and less — getting other people, computers, etc. to analyze the sheet.

Now imagine that someone says the reason why the numbers sum differently depending on the direction you read them is because of “magic”. Does this explain what is going on, or just make everyone give up and stop questioning? The fact that you can say “Magic!” in response to any strange-at-the-time phenomena makes it seem exactly like the latter.

And Harry Potter is the same thing: something we can imagine as an event (it’s like our world with laws, except a certain law doesn’t apply) despite being completely unable to imagine the explanation (how does one break a natural law?). The only thing we can do is say “Magic!” My epistemic naturalism is the thesis that “Magic!” or “Supernaturalism!” or “Divine Will!” nearly always take the role of making the question go away, and actually add nothing to our understanding of what is going on.

The only route I’ve seen that intrigues me so far is uncaused events, which you mentioned, so I’m going to explore that in a little bit. But does this help for now?

Watch Out for the Category Errors!

Your answer wrt the thought experiment begs the question. Your mention of a divine will skips ahead to a different issue, leaving the thought experiment behind. Perhaps fhwgwgd is incoherent on account of your definition of naturalism. And that would further beg the question (defining the problem condition out of existence).

But what am I unduly assuming without proving? I thought I have repeatedly justified why I can’t tell you whether a certain event is naturalistic or not — the problem lies with the proposed explanation, not with the event itself.

Asking “is a stick-to-snake event naturalistic?” is like asking “what is the color of justice?”. It’s a category error from the epistemic naturalism point of view. Instead you have to ask “is a stick-to-snake event explained by saying God wanted it to be that way and did so with his innately omnipotent will naturalistic?” — and I would say no. I would also say no to uncaused events. And I would keep doing so to both until I understood where the mechanism was and what was being proposed.

So epistemic naturalism is the idea that all supernatural claims are incoherent. Now, this gives me something to seriously grapple with in terms of uncaused events: either demonstrate that the concept of uncaused events are incoherent, or find a place for the uncaused within naturalism in a way that makes sense and does not destroy the concept of physical law. This is truly a challenge, and I worry that I might not be able to do either. …And if I don’t do either, you win some sort of positional concession from me, though I don’t know what yet.

An odd nightmare for philosophers

That Whole Thing About Randomness

It seems that if an uncaused event is possible then it is inexplicable in terms of causation (and does not meet the definition of “natural” under your definition of naturalism).

Yes, that seems definitionally true: Uncaused events cannot be explained with causation. My formulation of naturalism, and the naturalism I will defend as the only one that makes sense based on my understanding and the version most likely to be true given what I know, requires everything to have an underlying cause. Thus the existence of an uncaused event is the undermining of my naturalism.

Now I don’t think the only other possibility to naturalism is angels, and there are other naturalisms posited by other philosophers that do involve uncaused quantum events, but I don’t get how the uncaused events are supposed to work, nor do I know precisely what their definition of naturalism is. The demonstration of uncaused events would cause me to rethink a lot of things, dramatically. So I agree that this uncaused thing is a key thing to look at.

Defining Randomness

Joseph: Yes, you’re thinking like me now. So the result of the die is, apparently random, (perhaps if I used a German word for random, google says…zufällig, I would seem more philosophical), because of both some unknown data, and the complexity of the calculations involved.

Zufällig is an interesting and fun term, but I find it unnecessary — I would much prefer to go with the random-uncertain distinction:

Something is random if it is truly, mathematically random in the ontological sense: it comes forth uncaused without regard to law.

Something is uncertain if it is not fully predictable. A die roll is uncertain, yet probably not random — a die roll could also be considered evenly uncertain, since we cannot predict one outcome as more likely than the others. Things that are random are definitely also uncertain and perhaps evenly uncertain, but not necessarily the other way around.

Something is fundamentally uncertain if it is uncertain and will always be so, even in principle. This is Heisenberg Uncertainty / observer effect territory, where introducing the measurement device will always affect the measurement, and there is no way we could fix this. A perfectly accurate account of the future is fundamentally uncertain, for reasons I outline in “Free Will That Makes Sense”.

The Uncaused Thought Experiment

Bryan: And by way of further explanation, you can have a “law” of randomness that states x will happen 80 percent of the time while ~x will happen the remaining percent of the time. What that provides the naturalist is a fig leaf covering the fact that he doesn’t know what causes ~x to happen vs. x. That type of law, in the final analysis, does not permit complete explanations for apparently random phenomena.

I agree, this is an unfair dodge. There would have to be an explanation for why x occurs instead of ~x, or there are still things left to explain. One cannot claim to have explained what one has not actually explained. But what might Bryan have in mind?…

Bryan: Imagine a pool table. It has a cue ball on it. It has an 8-ball on it. Imagine the cue stick drives the cue ball into the 8-ball in a series of identical trials at the precisely identical vector and force (from identical starting locations). Yet the 8 ball goes in the left pocket 80 times out of 100 trials and into the right pocket the other 20 times. Obviously this forces you to think outside the naturalistic paradigm. But given that these results are strictly logically possible (they are not logically contradictory), what do you make of it? Is the movement of the 8-ball uncaused?

So what I hear you asking is that if we had some ability to “back up the universe” and “play it again with the exact same starting scenario”, we would notice that the 8-ball goes in a different direction than before. Thus some of the final consideration of which way the ball goes is completely undetermined and entirely, irreducibly, fundamentally arbitrary — the direction the ball goes in this world is not dependent upon anything at all.

This is indeed something I can imagine, so it’s not “square circle” territory. But given that we definitively are not able to back up the universe and replay it with all the same starting conditions and record the results of multiple trials, even in principle, we’ll obviously never be able to preform this experiment.

So now a couple of questions come to mind:

(1) In principle, how do we tell if something has a random or uncaused outcome, instead of a fundamentally uncertain one?
(2) Is there anything in the world that we can know to be random and/or uncaused?
(3) What are the implications of randomness and uncaused effects on choosing a worldview?

I’m going to use the rest of the essay to explore these.

Random vs. Uncertain vs. Fundamentally Uncertain?

Bryan: Yes, non-existent in the sense of not following lawful behavior in the traditional naturalistic sense. True randomness is qualitatively different from every type of (traditional) naturalistic randomness. The latter is always predictable in principle (if you knew the starting conditions sufficiently well you know how the die roll comes out), while the former is unpredictable in principle based on starting conditions.

This actually is a key problem though, since there can be truly deterministic systems that are still fundamentally uncertain — still can never be predicted. It is not always the case that if you knew the starting conditions sufficiently well you could know how the outcome comes out, because sometimes knowledge of the prediction will change the outcome.

Thus something can still be unpredictable in principle based on the starting conditions and still not be random. I don’t think naturalism has any problem for being consistent with such scenarios. The problem is wondering whether we can distinguish between something that is random and something that is just fundamentally uncertain, and tell which is which.

Bryan: Computers can now generate (it is said) true random numbers based on radioactivity. http://www.random.org/randomness/

I think this site misrepresents what it means for something to be “random” or “deterministic”; conflating uncertainty with randomness. For instance, die rolls are indeed deterministic and not random as far as I can tell, even if they are uncertain based on current technology. Same goes with atmospheric noise — likely to be deterministic, despite being uncertain.

But the last source of randomness mentioned, atomic decay, is indeed a potential candidate for randomness. And we actually have a way of telling if atomic decay is random — see if we can rule out the existence of hidden, currently unknown, variables that would determine atomic decay and/or see if we can identify an observer effect in our measurements of atomic decay.

This Dilbert comic provides an insightful look at what randomness means, as here the question is not about randomness, but uncertainty. Could you not attempt to predict the next number to be nine? How sure could you be, not knowing how the numbers are generated?

Is Quantum Mechanics Random?

Bryan: While no doubt there are some exceptions, it seems to be the holding of scientists that quantum particles represent true randomness.

When experiments in quantum mechanics were first underdone, it was found that certain parts of quantum mechanics functioned in a way that seemed completely unpredictable and completely undetermined by anything discovered by physics to date. Some notable luminaries did not like this indeterminacy (with good reason, since it is counter to all other parts of known science), such as Albert Einstein who reacted by saying “God does not play dice”.

These people adopted the hidden variable theory which states that our knowledge of quantum mechanics is incomplete, and that someday we will eventually discover the currently unknown factors that will allow for a fully predictable and determined quantum mechanics. They rested this resentment on the EPR Paradox.

The response is Bell’s Theorem, which showed that quantum mechanics could make certain predictions only if there were no hidden variables, and noted that these predictions were not yet demonstrated to be false, thus rendering the hidden variable theory unlikely. The “why” of this is complicated and beyond my ability to explain, though I hope to fix this soon.

Though a few remaining hold-outs assert that we need more and better Bell test experiments before we can ditch the hidden variable theory, it seems like Quantum Mechanics is random. Is there any hope?

Many Worlds to the Rescue?

Bryan: And you must have noted that scientists produced the “many worlds” interpretation specifically in order to avoid randomness.

Bryan is correct that the Many Worlds interpretation of Quantum mechanics (MWI) is indeed completely deterministic and not random in any way. Thus if MWI is true, we’ll have to look somewhere else to find randomness in the universe, and we currently have no other ideas of where to look. MWI thus saves naturalism from the shambles of the hidden variable theory.

This is a personal source of disagreement between us, because I see MWI as the most likely interpretation of Quantum Mechanics based on the current evidence and reasoning, whereas Bryan prefers, I think, the more popular and classic Copenhagen Interpretation (CI), which is as indeterministic and random as a theory can be.

But why favor MWI over CI? The reason is not actually as Bryan said, specifically to avoid randomness. In fact, the fact that we can avoid randomness is, while a big reason to favor MWI, not the only reason. Quite simply, CI assumes that while atomic decay goes into a superposition of simultaneous-decay-and-not-decay which is resolved to one of the two at random with observation, MWI assumes that the observation itself will also go into a superposition of observing-decay-and-not-observing-decay.

MWI thus does not have a special exception for observation that CI seems to have. And it’s important for this special exception to not be made, since doing so leads to what Eleizer Yudkowsky detracts as “the only non-linear, non-unitary, non-differentiable, non-local, non-CPT-symmetric, acausal, faster-than-light phenomenon in all of physics”.

That being said, I think that Bryan is being a touch misleading here — his comment makes it sound like MWI was formulated because physicists were too beholden to their naturalism to consider CI, or that the thought of randomness under their covers gives them nightmares. Instead, the ability to avoid randomness is a strong mark of parsimony — it is one strange fact of the universe we no longer need to postulate in order to make sense of things. This means that everyone’s favorite Ockham’s Razor gives the victory to MWI. (And given that the observational and mathematical predictions of both interpretations are the same, Ockham’s Razor plays a big role here.)

So what’s the bottom line of all of this? I’d say that the strong plausibility of the success of MWI and weak plausibility of the failure of Bell’s Theorem adds up to there being reasonable doubt over the existence of randomness. And if there’s no randomness, there’s nothing for naturalists to worry about.

The Buck That Stops in Too Many Places

Joseph: That is because a number, value, etc can be to all intents and purposes random, we cannot infer lack of any causation, and when a number of variables are unknown we have to be even more careful. I think the key difference between your view and mine, is I am saying these things are unknowable, unmeasurable, your view seems, please correct me, to be that this means they are non-existent.

Bryan: In the present case alluding to gods and angels simply makes clear that I do not equate the lack of a causally determined explanation with randomness (otherwise I could reasonably be accused of contradicting myself). “Explanation” to a philosophical naturalist, at least in my experience, means a naturalistic cause. So of course alluding to things the naturalist rejects do not add to the explanation. However, such explanations have potential advantages in terms of parsimony.

Bryan: The scientist concludes “uncaused” simply because he can’t come up with an explanation in terms of naturalism. It doesn’t mean that it can’t be caused by something non-naturalistic (and this is where the pool table analogy serves). There’s nothing in the science to disprove a non-natural explanation. All it does is make a natural explanation look exceedingly unlikely.

Here we have four views represented on how the universe can come to be:

The first, advocated by Joseph, is that we simply cannot know, even in principle — it’s a fundamental mystery.
The second, advocated by Bryan, is that the cause is supernatural — the result of angels and/or God.
The third, opposed by both Joseph and Bryan, is that the cause does not exist — the universe came into existence uncaused.
The fourth is a complete explanation of the underlying mechanism that allowed the universe to come into existence and the reason why conditions were in place for this phenomena to occur — notably absent because we do not actually have that science, at least at the moment.

Given these four views, what should we do? The fourth view can obviously be discarded because we do not have any information about any underlying mechanisms here, or even if they exist — we are in a state of uncertainty. But I see no reason why this uncertainty is fundamental, thus I would also reject the first view.

In fact, I would go even farther and reject all four views — the first three views are dangerous because while they can be applied to the universe, they work the same way as “magic” and could be applied anywhere else. Imagine that we were in a situation where we had no idea how lightning came to shock the ground, such as science a millennia ago.

Here, scientists and philosophers could just as easily say that lightning was a fundamental mystery, that lightning is supernatural, or that lightning strikes the ground uncaused. These are all-purpose non-explanations that can be implemented in any situation, and once one of the first three views is implemented, the fourth view is blocked from ever coming into existence, even if it does exist for lightning. The buck stops in too many places — the first three views can explain anything, and thus they really explain nothing

Thus there is a hurdle towards employing the three views — you have to find some way to justify why we can employ them as tactics here, and not as solutions to other problems or mysteries. Otherwise we get a brand new X of the Gaps, where “fundamental mystery”, “supernatural”, or “uncaused” is used to explain things like The Bloop.

But what do we do when we can’t apply any of the four views? Search for more data. We’re going to need more information from physics before we can determine how the universe came to be, or whether it is located within some larger multiverse structure, and whether this multiverse structure is infinitely old or not, etc.

Is there ever a time where we could apply one of the first three views? This is an open question for me — I can’t get over the hurdle outlined earlier. But there still is one potential solution to the origin of the universe that I have in mind…

The Lack of the Classical Origin

Me: (T)here was no “nothing” prior to the “something”, as this essay points out. The universe didn’t pop in, because that requires time where the universe wasn’t around, and there’s no such time.

Bryan: I think the reference to time was developed as a dodge (not developed by you, mind you–you’ve doubtless read it from others and decided it makes sense).

This is true. I did a double-back through my sources, and I think I found that this idea comes from Richard Carrier, though I don’t know where he got it from. I have not seen any other philosopher advocate for it. I don’t think it was developed as an intentional dodge and I do think it makes sense, but I’m open to criticism.

Bryan: Time isn’t the only way something can be prior to something else. Things can be logically prior regardless of time in the sense you’re using it. A cosmological model (such as what I say Krauss is saying), if it posits a universe arising from literally nothing then has nothing as a (logically) prior condition for any subsequent (resulting) condition regardless of any passage of time.

Right now, the perspective I’m chasing is not Krauss’s theory at all. And again, there is simply no period of nothing prior to the universe, there is simply the origin of space-time simultaneously in what would make sense on the B-Theory of time.

That nothing is logically prior is of no relevance — if there is no causal relationship between what is logically prior, there is no such rule that something can’t come from a logically prior nothing, just that something can’t come from a temporally prior nothing.

Though I must admit the whole concept of logically prior is not something I’m entirely familiar with, so I would love a non-cosmological example and further explanation of what this does to defeat my view.

Bryan: Mathematicians and physicists offer that more than one temporal dimension exists, moreover. Thus it isn’t clear that conditions such as those described by Krauss would be indescribable in terms of another temporal dimension. “Time” in a different sense, if you will. http://arxiv.org/abs/0812.3869

I agree these additional temporal dimensions can exist, but I don’t see what relevance they would have for the origin of the universe, given that the existence of these temporal dimensions also need to be accounted for.

So What Happens to Naturalism?

So what happens to naturalism?

I explained that I am defending the views that “everything reduces to atoms acting in a lawful manner” and “supernatural theories are incoherent”, and explained the relationship between the two. I then explained how this concept of epistemological naturalism can handle test-cases like Harry Potter, and why the event-versus-explanation distinction is so important.

I also looked at concepts of randomness and agreed that if they were demonstrated to exist, my naturalism would be false in any sense, and I would have to look for a different worldview that could incorporate it, though I think this would most likely lead me to a different concept of naturalism (perhaps “everything reduces to atoms, but those atoms only act lawfully most of the time”?).

But when we looked at randomness further, and after distinguishing it from the often confused fundamental uncertainty, we couldn’t demonstrate it to exist even where it is most likely to be found — in quantum phenomena — because of Bell’s Theorem and the Many-Worlds Interpretation.

I also offered a hurdle for appeals to randomness, the uncaused, the supernatural, and the fundamentally unknowable to clear before they can be accepted — one must answer what is different about this case that would prevent the non-explanation from being used in any other case to stop the need to find an explanation.

So I don’t find any reason to change my concept of naturalism at this current time, despite all the amazing discussion. And speaking of amazing discussion, it goes without saying that I thank you guys for the insightful commentary and supportive atmosphere necessary for the opportunities to explore these issues in detail.

I now blog at EverydayUtilitarian.com. I hope you'll join me at my new blog! This page has been left as an archive.

On 16 Jan 2012 in All, Atheism, Naturalism, Responses. 214 Comments.

214 Comments

#1 Bryan White says:
17 Jan 2012, 6:32 am
Your clarity, as usual, is admirable. And I do need to give this a second read just to help ensure I’m following the lines of thought correctly, but there’s one comment that can’t wait concerning this:

(T)he ability to avoid randomness is a strong mark of parsimony — it is one strange fact of the universe we no longer need to postulate in order to make sense of things. This means that everyone’s favorite Ockham’s Razor gives the victory to MWI. (And given that the observational and mathematical predictions of both interpretations are the same, Ockham’s Razor plays a big role here.)

Given that the MWI creates an infinity of new entities (innumerable unobserved universes) in order to eliminate randomness, it is a remarkably unsuitable candidate as a winner upon application of Ockham’s Razor.

I think you may have confused it with Ockham’s Swiss Army Knife (able to do anything) or something. ;-)

http://plato.stanford.edu/entries/ockham/#4.1
#2 joseph says:
17 Jan 2012, 9:40 am
@Bryan White,
I think I’ll stick with the answers I gave yesterday.
For the links (and the energy field) I would stick with Bertrand’s point; because we cannot describe exactly what happens at any one particle (or point in space), except via statistical analysis, does not mean we can assert, definately, there will never be a law that will, and conversely I can’t claim there is a law that describes this situation.

Most of the links seemed to assert the particles used had to be completely isolated (I would desperately like a physicist to tell me what this means, it sounds so much like the chemist, who claimed to have invented a universal solvent, his professor asked them what they were keeping it in), this, as far as I can tell, means we must be in total ignorance of starting conditions for a random result. I think the die example stands, if we deliberately went to every effort to ensure total ignorance of starting conditions we could say the result was effectively random. I have tried previously to understand bell inequalities (by reading a book with some pictures of rabbits on called something like “how to explain quantum mechanics to your dog”) I ended up drawing a bunch of diagrams that totally disagreed with the authors conclusions and gave up (I guarrantee I’m at fault). I have tried largely not to argue that definite spins and positions for quantum particles exist, at the moment I picture them as smeared out probability field, but I still think I’m ok to say something exists (there is something that we think of as an electron, photon etc), even if there aren’t hidden variables.

And if I’m wrong and it is genuinely acausal, the simplest of the unfalsifiable explanations for me is “it’s unknowable”, but I am totally unsure, in the (hypothetical) supernatural world, if Ockham’s Razor applies.

@Peter Hurford
I can’t be a pseudo-intellectual if you go around using english words like ‘uncertainty’ (yes it is much more clear, thankyou, but that adds to my point!).
#3 joseph says:
17 Jan 2012, 9:43 am
Also I want the number of commemts to hit 100.
#4 Tom Mitchell says:
18 Jan 2012, 9:52 am
Hello,

I hope you guys don’t mind me putting my two-sense in your conversation. I am sorry to say I have not read your 79 comments on the “Twelve Reasons I Don’t Believe in Supernatural Claims, Part I.” I read this essay, well most of it, and wanted to see what your thoughts were on my thoughts.

What I took to be the topography here is as follows ( please correct me if I am wrong)

First, I read Peter as stating that what he means as naturalism is more specifically the idea that every event in the universe has both a physical cause and effect. By labeling something as “magic, supernatural, divine will, etc” the individual/collective is not even attempting to understand the event they are describing. Sure polyjuice is polyjuice, but when Harry drinks a polyjuice potion it causes the natural territory of his body to transform. There is something that is happening. We can label that something as “unknown,” but all that does is deter our imaginations from discovering new fertile ground of knowledge to stand on. I would summarize Peter’s position as

– Accepting something as unknown hinders knowledge and provides no real benefit.

Now I must admit I am somewhat confused by the later 4/5ths of this essay. From reading it, it seems like the opposition’s argument is that in the universe there exist uncaused causes. An event that’s impetus has no physical origin? I agree with Peter when he says

I don’t get how the uncaused events are supposed to work.

In my mind any event I can trace to some chain of other events is caused. I probably will not be able to trace that chain of events back to its origin, but I do not think the best or most reasonable explanation for this is that its origins are non-physical. However, I am in agreement with you that “magic, divine will, the supernatural, etc” have some worth to be salvaged. I think my position is a combination of Peter’s and yours. Now that I described what I see to be the conversation, I will tell you my thoughts on the matter.

I agree with Peter that “the [issue] lies with the proposed explanation, not with the event itself.” I believe that all events happen for reasons and are intricately linked together. Even if there is some “uncaused cause,” the moment we are able to think of it, or pinpoint it, it becomes a real cause. If there exist “supernatural forces” they are only such until we are able to explain them. Now this is where I will bring up what I see to be the true argument of Joseph and Bryan.
The argument is not that some events happen for metaphysical reasons, but that there are some physical events, whose processes are untranslatable by the human apparatus. Or in other words, that there are things unknowable to humans due to the limitations of the human body.

Peter your defense of epistemological naturalism assumes that every aspect of reality is knowable to humans. Richard Rorty describes this mindset as one that views human cognition as the “mirror of nature,” where our minds reflect every aspect of the physical world we encounter onto our consciousness, making all of reality knowable. However the analogy itself contradicts the viewpoint. A mirror distorts, it inverts, it cannot capture temperature, depth, weight, etc of what the viewer is implying it captures. It is a poor representation of reality. I would go farther to say that it was never meant to be a representation of reality. A mirror is a mirror. It is only because of the unique relationship it has with a sentient entity that contains sufficient optic and imaginative capabilities that it has ever become anything more.

Bryan and Joseph, correct me if my thinking is completely out of line, but I imagined the point that you were trying to make is not that magic means something happen for no reason whatsoever, but that some reasons are beyond human understanding.

I think if fully adopted this is a dangerous idea that leads to a severe lack of imagination (as Peter has suggested). However, I do not think it is bad to have a healthy awareness of the fact that just because reality is ontologically composed of sub-atomic partials does not mean that the human mind is capable of comprehending it.

After all, what proof do with have that the humans are an accurate tool to measure reality? There is none. The idea that we are capable of understanding the myriad of causes and an effect that defines what we call reality is a hope some humans have (a faith that they have).

I am not saying it is a bad dream. I do think there are many situations where trying to understand reality benefits us, but that does not mean there are some situations where it will not. There are plenty of times when it is good to laugh, but to say it is always good to laugh is an over simplification of reality. Peter as you know I am an avid believer of moderation. This includes a notion of moderate logic. The a priori assumption that with enough effort we can understand everything seems illogical to me.

The ball is in anyone’s court who wants to play, I look forward to the game!
#5 joseph says:
18 Jan 2012, 10:29 am
@Tom Mitchell
Great post as I’ve come to exspect!

“Bryan and Joseph, correct me if my thinking is completely out of line, but I imagined the point that you were trying to make is not that magic means something happen for no reason whatsoever, but that some reasons are beyond human understanding.”

I think you’ve summed up my point of view, but not Bryans.

My argument has a minor nuance (read get out clause), in that I only think these subatomic events are unknowable according to our best current thoeries. I am aware there are cracks in these theories, i.e. uniting relativity and Quantum Physics in the description of things with immensely strong gravitational fields (or the ability to massively distort space time) but sizes on the planck scale, or smaller (black holes). So I would accept that I am calling off the search, or even wanting to. I am just saying that Bryan is correct, the causes of radioactive decay on the level of individual atoms, electrons changing energy levels, a specific region of space having high enough energy to produce a virtual particle are unknown, but according to our best current theories there are coherent reasons as to why (we can’t make a measurement without inducing a significant change).
#6 joseph says:
18 Jan 2012, 10:48 am
“So I would accept…” d’oh => so I wouldN’T accept…
#7 Tom Mitchell says:
18 Jan 2012, 11:13 am
Yes, I was really interested in quantum mechanics for a while and read a couple books on it.I agree with Bryan that many axioms of our current theories are founded on phenomena we really know little about (strong force, energy, gravity, to name a few).

From reading Peter’s essay it sounded like you and Bryan’s position were that these things are compeltely random/ without any type of logic. I do not know if I believe in complete randonomness, or even if I could comprehend what that would be. Personally I think there must be some pattern to these things, I just don’t think humans are cognitively equipped to comprehend it.

It really is a brain buster though. Even though I do not think humans can comprehend all aspects of reality, I do think we could evolve into better tools for this particular trade (representaion of reality). Most anthropologists I have read on the subject argue that for the past several millena humans have shifted from natural to cultural evolution. Where rather than further specializing our bodies as a species, we remain relatively unspecialized and then later on adapt to highly specialized cultures. I think this is a fascinating idea, one I am not doing justice in such a breif explanation, but I must question my own a priori acceptance of it. Is it really true that the primary impetus of homo sapien evolution is cultural? that we have reached the epitome of natural change? I have no idea.

Fruthermore is it accurate to view cultural evolution as symbolic stagnation unable to develop emergent qualities? Again I have no idea. I am not even sure I understand the full implications of this second question. I apolgoize in advance for incoherence or lack of clarity, what i type from this point on is an improvisation of thought.

I. Human as Tools.
A. Humans are poor tools for representation reality.
B. Humans are exceptionally powerful tools for engineering reality.
C. Humans are tools capable of improving their function.
* Are tools capable of not just improving but redefining their function?
– It doesn’t matter, because humans are tools that engineer reality, the tool itself is a part of reality, therefore capable of being reengineered.

II. What is the state of Human evoltuion?
A. Do humans still evolve or have we perfected niche construction to a point where naturallly there will be no further change.
B. can humans cause an orthogenetic evoltuion?
* Is culture a type of orthogenetic evoltuion
#8 Bryan White says:
18 Jan 2012, 12:23 pm
I’m bemused to find the tables turned on my worldview. After so many discussions where my views are attributed entirely to imagination, now they have the danger of stifling it! :-)

We each have an epistemological choice: Conform reality to our world view or conform our world view to reality. My point in embarking on this conversation was to point out (and/or discover whether) Peter’s expression of his world view leads, ironically, to making questions go away.

Does true randomness occur? Peter and Joseph lean toward no. Tom is at the very least skeptical. I don’t think I can say that any of you have closed the door on the question, but there is a danger of leaving the door closed to reality. I’ll reiterate my latest point that a “many-worlds” interpretation is about the strangest candidate for parsimony that I can even imagine. “Many-worlds” certainly doesn’t explain randomness, if true randomness exists (I was going to add “in this universe” but thought better of it!). It makes the question go away.
#9 joseph says:
18 Jan 2012, 12:33 pm
@Bryan White,
“I don’t think I can say that any of you have closed the door on the question”
I concur! But ’tis a wonderfully intriguing question and discussing it is delightful.
#10 Tom Mitchell says:
18 Jan 2012, 2:12 pm
We each have an epistemological choice: Conform reality to our world view or conform our world view to reality.

Very nice sentence. Being the pragmatist that I am, I would ask what do you see as the pros and cons of each of these epistemological poles.
#11 Tom Mitchell says:
18 Jan 2012, 2:16 pm
@ Bryan

I was not trying to close the door to true randomness, but rather to substitute the question with a questioning of the question itself. Is knowledge about true randomness or absolute order knowable to humans?
#12 Peter Hurford (author) says:
19 Jan 2012, 3:16 am
Is MWI Ruled Out by Ockham’s Razor?

Bryan: Given that the MWI creates an infinity of new entities (innumerable unobserved universes) in order to eliminate randomness, it is a remarkably unsuitable candidate as a winner upon application of Ockham’s Razor.

Bryan is right about a few things here. The Many-Worlds Interpretation of Quantum Mechanics (MWI) is just that — an interpretation of the facts, not a set of facts itself. There is no way of telling it apart from the classical Copenhagen Interpretation (CI) by scientific observation or mathematical implication.

As I said before, this means it is one of the few places where we can get a lot of mileage out of Ockham’s Razor, which is supposed to tell us which theory to support when we have two otherwise identical hypotheses. And the implications of which interpretation we ultimately go with are large — as you can tell from this conversation, it could mean whether or not we think there is randomness (in the true ontological sense, see the above essay for explanation) in the universe, or whether naturalism is justified.

But luckily for our debate, Ockham’s Razor is not something that can be applied however you want — otherwise Bryan and I would be at an impasse, both using the Razor to justify our own positions. Instead, the Razor is used in a very precise way to rule in favor of a specific quantum interpretation. And, surprisingly, that interpretation favored by the Razor is MWI.

Now this my seem weird. Doesn’t MWI postulate that there are a bajillion of other worlds out there, conveniently unseen to us? Doesn’t Ockham’s Razor say we should not multiply entities beyond necessity? And given that CI can explain all of quantum mechanics with just one world, isn’t MWI multiplying an entity (worlds) beyond necessity? Thus, shouldn’t we go with CI?

~

To see why not, I’m adapting this from Eliezer Yudkowsky’s essay “Belief in the Implied Invisible”: imagine we are observing the light from a very-far-away galaxy. However, at exactly the time you are reading this sentence, we stop seeing the light from this galaxy because due to the metric expansion of space, it falls outside our light cone, and any light sent to us is not able to get to us fast enough to make up for the expansion of space. Do we decide to believe that this galaxy suddenly stops existing?

The answer is no. But why? The yes-galaxy and the no-galaxy theories now have identical empirical consequences, and are in the same position as MWI and CI. Yet the yes-galaxy theory contains one additional entity: the galaxy outside our light cone. So why not adopt no-galaxy on the basis of Ockham’s Razor?

The answer is that doing so violates nearly every law in the current book — the second law of thermodynamics and the law of conservation of energy both say that galaxies can’t just spontaneously disappear like that. You have to make brand new laws to account for why the galaxy suddenly disappears when it leaves the light cone, and this would mean multiplying laws beyond necessity, violating the Razor. The galaxy still exists, because its continued existence is a logical implication of the most simple account of physics found to explain all the data so far.

This is also why we can’t believe in undetectable garage dragons — they are not logically implied by the most simple account of physics, even if they are just as invisible as the galaxy.

And lastly, this is why we must accept MWI. If you look at the most simple account of physics found to explain all the data so far, including that from quantum mechanics, you will find that macroscopic objects, like observers, enter into the same kind of superpositions as microscopic quantum objects. You would need a special exception, an additional law, to explain why there is only one world and why superpositions only apply to microscopic things. Thus MWI follows directly from the Razor, not in opposition to it.

(Note: Yes, my essay “The End of Cartesian Demons” does make it sound like things we can’t interact with, even in principle, don’t exist. I think it’s easy to explain why that’s not what I was trying to say and why my application of the Razor here is entirely consistent… I just haven’t gotten around to saying so yet. It’s on the to-do list.)

More comments addressing randomness, unknowability, and stuff Tom did forthcoming tomorrow (later Thursday). Hopefully this is enough to keep you discussing for now.
#13 joseph says:
19 Jan 2012, 4:53 am
@Tom Mitchell
Your ideas of cultural evolution remind me somewhat of the Discworld:Roundworld series (Pratchett, Cohen and Stewart I think), they often discuss the idea of stories as cultural programming, and humans as Pan Narrans, the story telling ape…
Also I found this funny, it may be supportive of your theory:
http://www.smbc-comics.com/index.php?db=comics&id=1260
#14 Tom Mitchell says:
19 Jan 2012, 9:02 am
I have never heard of discoworld, but recently I have been reading a lot about narrative paradigms in various fields of study. One of the books I read is sub-titled Homo Narrans, so I am familiar with the idea of a story telling ape, and support it. I do not think it is possible to pick one key trait to define the human species. Rather one would need to describe the complex interaction of a cluster of essential traits. That said, the fact that humans process information, time, and other natural phenomena through a narrative is without a doubt one of those axioms.
#15 joseph says:
20 Jan 2012, 12:06 am
Ummm….Terry Pratchett is a celebrated populist, English, Fantasy-Satirist…here’s a link, might not be to your standards:
http://tvtropes.org/pmwiki/pmwiki.php/Discworld/TheScienceOfDiscworld
#16 Bryan White says:
20 Jan 2012, 3:49 am
Discoworld sounds scary! ;-)
I’m at least familiar enough with Pratchett to find amusement in the typo. But on to the point.

About this time yesterday, when I was reading Peter’s case for MWI as an application of Ockam’s razor, I had a feeling akin to a person a couple of moves away from losing a chess game. Or maybe one move away and the opponent has uncharacteristically refrained from declaring “Check.” I pondered with dismay the possibility of needing to immerse myself in QM theory in order to even continue my end of the conversation.

But a day can make a big difference.

(Aside to Peter:
I’d like to delay one more moment for the continued heaping of praise your writing, Peter. I’m fairly miserly with praise, but you’re just plain excellent at communicating clearly. It’s a great skill. I was having fun reading even while considering my prospects of an effective rebuttal rather bleak.)

All that said, it occurred to me that despite the well-crafted words and persuasive language, his reply did not support favoring MWI on the basis of Ockham’s razor. The razor prefers simpler explanations where the explanatory power is equal. But much of the reply communicated the idea that MWI stands alone in explaining all the data. We don’t require Ockham’s razor in a case like that.

As a result, my objection that the many worlds feature of MWI makes it an unlikely candidate to win an Ockham’s razor contest is on pretty decent footing.

We’re left, of course, with the issue of MWI as the proposed best explanation for the observed data. And on that point I do have some objections. Doubtless I stand lowermost on our local totem pole of QM knowledge, but I made a comment in the other thread that seem potentially problematic for MWI.

I wrote that many worlds represents a problem for determinism.

Now is a good time to unpack that statement. In a nutshell, I’m going to argue that MWI explains too much. It explains so much that it may prove as unpalatable to the naturalist as Santeria.

They key issues? How many worlds? And what are they like?

Some of the QM materials I’ve read refer to all “possible” worlds. But if a god is possible then we have universes that feature a god or gods. How do we know this isn’t one of them?

But perhaps there are some practical bounds on the possible worlds. Using the double slit experiment as a guide, we do not observe light everywhere but rather in a counterintuitve pattern. Yet even if we dispense with gods as a possibility (at least for the sake of argument), we’re still left with a determinism that is less than a shadow of its former self.

This world, as it is, apparently has multiple futures (and please immediately correct me if I’m wrong).

We either have world A that ends in worlds X … X(x) or else isomorphic worlds A (1 … x) that end in worlds X(1 … x) (branching pattern or eternal parallel). Not to rule out both. And if we have different outcomes from identical starting points then we have done exactly what we set out to avoid–break the (deterministic) laws of physics. And, returning to the parallel of the double slit experiment, do observations obliterate some number of the many worlds? Do we recreate the problem from Peter’s analogy, only bigger (a universe that suddenly pops out of existence)? The problem of randomness is solved, but at the cost of determinism. Neither really means anything unless the many worlds can be independent of each other to the point that we have both random and deterministic worlds.

I’m eager to hear suggestions as to how to understand the nature of the many worlds so that my thought experiments have the closest possible relationship to the MW conceptions favored in this group. I would not knowingly keep company with straw men.

So it’s been a strange 24 hours. I went from thinking I might not have a reply in the foreseeable future to an absolute eagerness to come back and spill. I hope I’ve achieved 10% or more of Peter’s clarity; lacking that I’ll be happy to muddle things up even more for those who have questions about what I’m trying to say. ;-)
#17 Bryan White says:
20 Jan 2012, 4:01 am
One more point. Many worlds also appears to present a problem for logic.

Joe blinks at time t

Joe does not blink at time t

We have a contradiction if existent universes featuring these conditions are isomorphic at time t-1, based on the notion that Joe and Joe are Joe at the same time and in the same sense.
#18 joseph says:
20 Jan 2012, 4:49 am
@Bryan White
A brief point while I consider a fascinating post.
“Some of the QM materials I’ve read refer to all “possible” worlds. But if a god is possible then we have universes that feature a god or gods. How do we know this isn’t one of them?”

I think this is a slight confusion over multiple universes (cosmology) and many world’s interpretation of quantum physics. In short as I understand it any of the many worlds would have identical laws of physics to ours, whereas multiple universes have the possibility of differing physical constants (though many are unstable). So any God that would arise in a quantum many world (on I go, destroying the english tongue) would be a naturalistic God…
#19 Bryan White says:
20 Jan 2012, 5:07 am
As I tried to emphasize in my reply to Peter, I’m more than happy to relegate my thought experiments to the notions of many worlds favored within our group. I’m not blindsided by the stipulation that the many worlds find no room for a traditional god or gods.
#20 joseph says:
20 Jan 2012, 5:57 am
I probably should have said “minor point” rather than “brief point”, sorry if I was being pedantic.
Putting my cards on the table I’m not particular enamoured of the CI or MWI…
#21 joseph says:
20 Jan 2012, 10:56 am
@Bryan White
I want to be a little careful about this, because my body is aching from a few hours of training and I’m using beer as a muscle relaxant…
The dilemna of the 2 Joes, is this not a re-wording of our initial dilemna? I.e. We have a region of space that may or may not instantiate a virtual particle? It may do either given the uncertainty of the starting conditions?

If it makes anything clearer i was thinking about the uncertainty of ions (mainly sodium and potassium), the uncertainty of the conformation of ion channels near the cell membrane of the relevant neurones, and the lower uncertainty of the positions of neurotransmitters around the synaptic cell membrane…
#22 Bryan White says:
20 Jan 2012, 1:59 pm
It may do either given the uncertainty of the starting conditions

Your suggestion appears to imply infinite universes in eternal parallel (rather than the branching model) with no two universes alike. But does it solve the problem? “Joe” might be in every respect identical in our two different cases except one of them gets something in his eye at time t while another Joe precisely isomorphic at time t-1 does not. So far as I can tell, the contradiction is still implied.
#23 joseph says:
20 Jan 2012, 11:37 pm
Yes, sort of, so the dilemna for the Copenhagen Interpretation is we can get one outcome, or the other, but can’t say which.

The dilemna for the Many World Interpretation is you get both.

Both would seem to depend on Heisenberg Uncertainty.

So I’m not solving it, so much as noting a similarity.
#24 joseph says:
21 Jan 2012, 12:26 pm
So…sort of thinking out loud, maybe to myself, I’d note a few things.

1) Heisenberg Uncertainty would prevent us from saying 2 universes are identical, only identical within so-and-so parameters.

2) Quantum Events cannot be said, either in MWI or CI, to be classically deterministic.

3) Large entities, such as planets, (perhaps large collections of ions, neurotransmitters, ion channels) with large collections of molecules etc, I’d guess the uncertainty would become lower, as the importance of less statistically likely events would decrease (?).

4) Hidden variables may change all that, be the theory seems to be contradicted by experimental data thus far…
#25 Peter Hurford (author) says:
22 Jan 2012, 4:22 am
It’s been a bit before I’ve weighed in on this discussion, so I want to discuss a few more points.

Could Quantum Mechanics Just be Unknowable?

Joseph: For the links (and the energy field) I would stick with Bertrand’s point; because we cannot describe exactly what happens at any one particle (or point in space), except via statistical analysis, does not mean we can assert, definitely, there will never be a law that will, and conversely I can’t claim there is a law that describes this situation.

Unfortunately, Bertrand Russell died a mere six years after John S. Bell published his first paper. Here, Russell is advocating the same “hidden variable theory” that I am now rather sure is ruled out by Bell’s Theorem.

How exactly does Bell’s Theorem rule this out? I’ve been trying to get a grip on this through studying, but it’s proving pretty difficult. Feel free to take a stab at http://plato.stanford.edu/entries/bell-theorem/ or http://lesswrong.com/lw/q1/bells_theorem_no_epr_reality/ if you want.

My horrendously incomplete summary is going to go like this: when you have two entangled photons, measuring one can tell you information about the characteristics of the other, no matter where that other is. By transmitting photons at different polarizations, you can get knowledge about different characteristics of B. The problem is that, very generally and specifically speaking, different characteristics you learn about B are contradictory — you learn one characteristic from one measurement and a contradictory characteristic from a different measurement.

This simply can’t be solved by assuming there is only one version of the photon, so thus there must be multiple versions of the photon. Yet, when we observe the photon, we only see one version. Thus either the multiple versions of the photon suddenly become one photon (collapse of the wave function under CI) or there are multiple observers who each see one version of the multiple photons (MWI).

~

Joseph: And if I’m wrong and it is genuinely acausal, the simplest of the unfalsifiable explanations for me is “it’s unknowable”, but I am totally unsure, in the (hypothetical) supernatural world, if Ockham’s Razor applies.

“It’s unknowable” is not an explanation, even an unfalsifiable one. It just might explain why we don’t have an explanation. I don’t think you get to say “The world is still naturalistic somehow, we’ll just never know how it is”, because you could say that about *any scenario*, even if directly facing God. It’s like saying “Zebras can fly, but this ability for flight will never be observed nor can it ever be understood” — kind of meaningless.

~

Tom: First, I read Peter as stating that what he means as naturalism is more specifically the idea that every event in the universe has both a physical cause and effect. By labeling something as “magic, supernatural, divine will, etc” the individual/collective is not even attempting to understand the event they are describing.

I find this to be an exceptionally good summary of my position.

~

Tom: Peter your defense of epistemological naturalism assumes that every aspect of reality is knowable to humans. Richard Rorty describes this mindset as one that views human cognition as the “mirror of nature,” where our minds reflect every aspect of the physical world we encounter onto our consciousness, making all of reality knowable.

Where did I say that every aspect of reality must be knowable to humans? Or how does epistemic naturalism imply that? All it does is say what you just said — appeals to the supernatural are not actual explanations.

I admit the existence of observer effects, where certain parts of reality cannot be known, even in principle. I even give an example (you will never be able to predict the future with perfect reliability) in my essay “Free Will That Makes Sense”.

~

Tom: Bryan and Joseph, correct me if my thinking is completely out of line, but I imagined the point that you were trying to make is not that magic means something happen for no reason whatsoever, but that some reasons are beyond human understanding.

I think this may accurately represent Joseph’s position, but I am doubtful this is what Bryan is saying. Though, he’d have to comment on it himself.

~

Tom: After all, what proof do with have that the humans are an accurate tool to measure reality? There is none. The idea that we are capable of understanding the myriad of causes and an effect that defines what we call reality is a hope some humans have (a faith that they have).

We are an accurate tool at measuring many parts of reality, and the proof is that our predictions about the future obtain in our experiences. See “The Origin of Truth” and “Meaningfully True” if you want my full opinion on this.

~

Tom: The a priori assumption that with enough effort we can understand everything seems illogical to me.

I’m pretty sure I do not make this assumption.

~

Bryan: We each have an epistemological choice: Conform reality to our world view or conform our world view to reality. My point in embarking on this conversation was to point out (and/or discover whether) Peter’s expression of his world view leads, ironically, to making questions go away.

Well, I certainly hope that we are conforming our world view to reality — that’s the path I hope to walk because it’s the only way I will be able to make accurate predictions about how things will work.

Does my worldview lead to making questions go away? More on that in response to your challenges against MWI on randomness and determinism forthcoming.
#26 joseph says:
22 Jan 2012, 5:09 am
““It’s unknowable” is not an explanation, even an unfalsifiable one. It just might explain why we don’t have an explanation”

I find it similar to “It is the supernatural, which is unknowable”, you’re right I would consider them non-explanations, mine being a simpler one.

As for Bells Theorem ruling out hidden variables, for the most part it seems to have been accepted that it has, and what is going on is the closing of any loopholes. I am cautious enough not to rule it out, but I am one of those sad individuals who is hoping to live long enough to see another paradigm shift in physics…I’m hoping string theory produces something falsifiable.
#27 joseph says:
22 Jan 2012, 5:21 am
From what I understand Bell’s theorem shows a difference between what would happen if, say, a photon existed in a set polarisation before measurement, or if it existed in a superposition of possible states only being set in one polarisation after measurement.

What I find confusing myself is the act of measuring is passing a photon through a piece of crystal, which filters out certain polarisations, so I can’t work out how you separate “measuring” the polarisation of the photon, and “setting” it.

In either case, no-one seems to be arguing for the non-existence of a photon, and as far as I’ve been able to work out all efforts at measurement seem to interfere with the measured…yeah I am lost.

@Bryan
Keep forgetting to say, but “Discoworld” sounds like a Travolta movie!
#28 joseph says:
22 Jan 2012, 8:18 am
@Peter Hurford
Also I can’t answer whether if Hidden variables don’t exist, would this mean that the quantum state is a) unknowable b) a superposition; if so does that count as knowable c) non-existent (my least favourite)
#29 joseph says:
25 Jan 2012, 12:36 am
@Brian White,
An obvious reply, maybe too obvious:

“One more point. Many worlds also appears to present a problem for logic.
Joe blinks at time t
Joe does not blink at time t”

Counterintuitive though it is, if a human is viewed as a wave (or having a wave form) is this still a logical problem?
#30 Bryan White says:
25 Jan 2012, 2:33 am
@ Joseph, who wrote: (I)f a human is viewed as a wave (or having a wave form) is this still a logical problem?

I don’t know. I’d have to hear the argument as to why the wave form aspect would matter. If it eliminates the possibility of many worlds exist apart from this one then it appears to resolve the difficulty. But I’m not really sure what it is you’re suggesting, actually.
#31 joseph says:
25 Jan 2012, 7:07 am
Well, more thinking out loud, as I understand both CI and MWI are based on the wave like properties of …entities…on the quantum scale, rather than exclusively their particle like behaviour.

Now to give a human example is to give an example that most of us will intuitevely think of in terms of classical terms (as is far more pragmatic, for everyday life). But to think of a human as a composite wave form, or at least being able to be described as such, then 2 (or more) possible events are logical for a wave. You would have a series of impossible events, improbable events, and highly probable. I guess depending if the interference pattern is constructive or destructive.

Take the double slit experiment, the results are illogical if light is described as a particle, but logical if they are described as a wave.

If you take an event described by CI or MWI, and said it had to be described only in terms of particles, the results would be impossible…
Writing that might have been a big waste of time, sorry if si.
#32 Kassi says:
27 Jan 2012, 12:12 am
That’s the best answer by far! Thanks for cntroibuting.
#33 Peter Hurford (author) says:
1 Feb 2012, 1:57 am
I promise you guys that I haven’t forgotten this comment discussion, but replies here take a few hours of background research and I just haven’t recently found myself with the time to get to the bottom of these things. I hope to get to do so sometime in the next week or so, though.

This is actually good news in disguise, though, as it’s a strong indication we’re having a well-grounded, productive, and insightful conversation. I hope to contribute to it again soon!

~

Bryan: (Aside to Peter:
I’d like to delay one more moment for the continued heaping of praise your writing, Peter. I’m fairly miserly with praise, but you’re just plain excellent at communicating clearly. It’s a great skill. I was having fun reading even while considering my prospects of an effective rebuttal rather bleak.)

Also, thanks for the compliments. I hope you don’t mind, but I added this to my people praising me section. :)
#34 joseph says:
3 Feb 2012, 3:51 am
No worries from me.
#35 joseph says:
6 Feb 2012, 1:10 am
@Kassi
If that was for me then thanks muchly, if for someone else then embarrased apologies for stealing praise…
#36 Bryan White says:
6 Feb 2012, 4:16 am
“I hope you don’t mind, but I added this to my people praising me section. :)”

I certainly don’t mind, but I think “Linda” (whoever she is) is going to be surprised at what she said about you.
#37 Peter Hurford (author) says:
9 Feb 2012, 10:50 pm
Hah, I finally figured out what you meant. There was an HTML glitch (missing ” in the link) that accidentally combined two of the comments together into one. Ha! Fixed!

Also, this comment officially renews my commitment that comments here are indeed forthcoming. Ha again! My weeks are too busy…
#38 joseph says:
9 Mar 2012, 7:47 am
@Peter Hurford,
This is one of those subjects that’s on my mind.
One of those itches that you can’t quite reach…
I believe “time symmetric” quantum interpretations may be of interest to you, as they seem to fulfill the criteria you set in accepting MWI.
If you are reading around this area I’d welcome your thoughts, and Bryan White’s.
#39 Bryan White says:
9 Mar 2012, 12:37 pm
As for me, I’d have appreciated either a sketch of the time symmetric hypothesis or a link describing the view along the lines you’re thinking. I went here to find out about it:
http://arxiv.org/html/physics/9812021v2

I was happy to see that the author confirmed one of my impressions from the first read in his conclusion:

“Two universes are far better than the infinity of universes in a many-worlds version of quantum theory, and in any case we are in need of at least one more universe’s worth of baryonic mass.”

If TS theory explains the same phenomena as MW then it is preferable on the basis of Occam’s Razor to MW. My other impression is that TS leaves intact true randomness, and the question is whether true randomness breaks a physical law that we need to keep intact or simply represents an observation that is inexplicable in principle.
#40 joseph says:
10 Mar 2012, 4:11 am
Hi Bryan White,
Glad to see you! Here is a little trail of wiki articles I read in an attempt to understand things:

http://en.wikipedia.org/w/index.php?title=Interpretations_of_quantum_mechanics

http://en.wikipedia.org/wiki/Yakir_Aharonov

http://en.wikipedia.org/wiki/Weak_measurement

Firstly, I was surprised by how many interpretations there are, then shocked by the opportunity it affords to pick the theory that support whichever belief system you prefer.

I noted Peter Hurford thinks that:

“If I’m right about what I think I am, strong determinism is specifically required by the best theories of time and quantum mechanics in modern physics. Thus determinism would be falsified by demonstrating different theories of time and quantum mechanics that specifically require in-determinism, like what would be the case if the Copenhagen Interpretation of Quantum Mechanics or the A-Theory (tensed, presentist theory) of time were true.”

This was in a response to a question as to the falsifiability of any quantum interpretations. I believe the time symmetric quantum interpretations satisfy the same criteria, and I think, despite being a hidden variable theory they account for bell inequalities. They do so at the cost of retro-casuality. Personally this is an idea that I find more acceptable on a gut level than MWI. Which is not a logical argument at all. I baulk at MWI’s many universes, CI seeming dependance on an observer for decoherence, and TSI’s retrocasuality. The idea of particles as stable closed time loops fascinates me (Spock eyebrow raise).

You’ll note that in the summary table:
1. TSI is deterministic
2. Broadly speaking deterministic and indeterministic theories are of a similar number, there are agnostic theories (the ensemble interpretation; http://en.wikipedia.org/wiki/Ensemble_Interpretation).

I’m still interested in how the supernatural explains things further, as far as I can see the supernatural world is logical, or illogical. If illogical we are back to square uno. If logical then causes are required in the supernatural world to, which, following the logic “causation equals determinism”, would seem to indicate the supernatural word is deterministic.

I appreciate I have just shown how little a naturalistic consensus there is on this! I can’t help feeling that looking for supernatural answers at the very least leaves us with all the same questions.
#41 Bryan White says:
10 Mar 2012, 4:40 am
Ok, thanks for the linked material (I confess to having an anti-Wiki bias–I tend to use such sources only when my prior familiarity with the material helps confirm its reliability).

I have no further comment on the TS interpretation at this time, though I won’t rule out piggybacking on the comments of others.
#42 joseph says:
10 Mar 2012, 4:46 am
“confess to having an anti-Wiki bias–I tend to use such sources only when my prior familiarity with the material helps confirm its reliability”

That is admirable! I’ll bear it in mind, I admit I was being lazy.
#43 joseph says:
10 Mar 2012, 11:51 pm
@Peter Hurford

The more I go down the rabbit hole the more interesting it gets, even as a non-physicist this amounts to poking my head into the hole and saying “oh, pwetty, numbers, equations and stuff”.

There may be reason to reconsider this statement:

“The response is Bell’s Theorem, which showed that quantum mechanics could make certain predictions only if there were no hidden variables, and noted that these predictions were not yet demonstrated to be false, thus rendering the hidden variable theory unlikely. The “why” of this is complicated and beyond my ability to explain, though I hope to fix this soon.”

From http://plato.stanford.edu/entries/qm-bohm/

”

One of the achievements of John Bell was to replace the “arbitrary
axioms” (Bell 1987, page 11) of Kochen-Specker and others by an
assumption of locality, of no action-at-a-distance. It would be hard to
argue against the reasonableness of such an assumption, even if one
were so bold as to doubt its inevitability. Bell showed that any
hidden-variables formulation of quantum mechanics must be nonlocal, as,
indeed, Bohmian mechanics is. But he showed much much more.

In a celebrated paper published in 1964, Bell showed that quantum
theory itself is irreducibly nonlocal. This fact about quantum
mechanics, based as it is on a short and mathematically simple
analysis, could have been recognized soon after the discovery of
quantum theory in the 1920′s. That this did not happen is no doubt due
in part to the obscurity of orthodox quantum theory and to the
ambiguity of its commitments. It was, in fact, his examination of
Bohmian mechanics that led Bell to his nonlocality analysis. In the
course of his investigation of Bohmian mechanics he observed that (Bell
1987, p. 11):”

”

It is remarkably difficult to get this point across, that
determinism is not a presupposition of the analysis. (Bell
1987, p. 143)

Despite my insistence that the determinism was inferred rather than
assumed, you might still suspect somehow that it is a preoccupation
with determinism that creates the problem. Note well then that the
following argument makes no mention whatever of determinism. …
Finally you might suspect that the very notion of particle, and
particle orbit … has somehow led us astray. … So the following
argument will not mention particles, nor indeed fields, nor any other
particular picture of what goes on at the microscopic level. Nor will
it involve any use of the words ‘quantum mechanical
system’, which can have an unfortunate effect on the discussion.
The difficulty is not created by any such picture or any such
terminology. It is created by the predictions about the correlations in
the visible outputs of certain conceivable experimental set-ups. (Bell
1987, p. 150)”

Also, just because it’s pretty:

http://plato.stanford.edu/entries/qm-bohm/figure1.gif

So, to be neutral, it seems bell inequalities are either picking a fight with locality or determinism. Either way, as far as I can tell, our understanding of causality is changed.
#44 joseph says:
10 Mar 2012, 11:58 pm
I have no idea why Android mashed up the formatting
#45 Dov Henis says:
7 Apr 2012, 3:03 am
There cannot be randomness in an evolving universe!!!

Higgs Particle? Dark Energy/Matter? Epigenetics?
YOK!
Update Concepts-Comprehension…
http://universe-life.com/2011/12/13/21st-century-science-whence-and-whither/

Evolution Is The Quantum Mechanics Of Natural Selection.
The quantum mechanics of every process is its evolution.
Quantum mechanics are mechanisms, possible or probable or actual mechanisms of natural selection.

=================
Universe-Energy-Mass-Life Compilation
http://universe-life.com/2012/02/03/universe-energy-mass-life-compilation/

A. The Universe

From the Big-Bang it is a rationally commonsensical conjecture that the gravitons, the smallest base primal particles of the universe, must be both mass and energy, i.e. inert mass yet in motion even at the briefest fraction of a second of the pre Big Bang singularity. This is rationally commonsensical since otherwise the Big would not have Banged, the superposition of mass and energy would not have been resolved.
The universe originates, derives and evolves from this energy-mass dualism which is possible and probable due to the small size of the gravitons.
Since gravitation Is the propensity of energy reconversion to mass and energy is mass in motion, gravity is the force exerted between mass formats.
All the matter of the universe is a progeny of the gravitons evolutions, of the natural selection of mass, of some of the mass formats attaining temporary augmented energy constraint in their successive generations, with energy drained from other mass formats, to temporarily postpone, survive, the reversion of their own constitutional mass to the pool of cosmic energy fueling the galactic clusters expansion set in motion by the Big Bang.

B. Earth Life

Earth Life is just another mass format. A self-replicating mass format. Self-replication is its mode of evolution, natural selection. Its smallest base primal units are the RNAs genes.
The genesis of RNAs genes, life’s primal organisms, is rationally commonsensical thus highly probable, the “naturally-selected” RNA nucleotides. Life began/evolved on Earth with the natural selection of inanimate RNA, then of some RNA nucleotides, then arriving at the ultimate mode of natural selection, self-replication.

C. Know Thyself. Life Is Simpler Than We Are Told

The origin-reason and the purpose-fate of life are mechanistic, ethically and practically valueless. Life is the cheapest commodity on Earth.
As Life is just another mass format, due to the oneness of the universe it is commonsensical that natural selection is ubiquitous for ALL mass formats and that life, self-replication, is its extension. And it is commonsensical, too, that evolutions, broken symmetry scenarios, are ubiquitous in all processes in all disciplines and that these evolutions are the “quantum mechanics” of the processes.

Human life is just one of many nature’s routes for the natural survival of RNAs, the base primal Earth organisms.

Life’s evolution, self-replication:

Genes (organisms) to genomes (organisms) to mono-cellular to multicellular organisms:

Individual mono-cells to cooperative mono-cells communities, “cultures”.
Mono-cells cultures to neural systems, then to nerved multicellular organisms.

Human life is just one of many nature’s routes for the natural survival of RNAs, the base Earth organism.
It is up to humans themselves to elect the purpose and format of their life as individuals and as group-members.

Dov Henis (comments from 22nd century)
An Embarrassingly Obvious Theory Of Everything
http://universe-life.com/2011/12/10/eotoe-embarrassingly-obvious-theory-of-everything/
#46 joseph says:
7 Apr 2012, 9:47 am
This article was quite (as far as articles about Quantum Mechanics go) easy on the mind:

http://math.ucr.edu/home/baez/physics/Quantum/bells_inequality.html

Key Points were:

How do we reconcile the fact that photon 2 “knows” that the x-spin of photon 1
has been measured, even though they are separated by light years of space and far too
little time has passed for information to have travelled to it according to the rules of
special relativity? There are basically two choices. We can accept the
postulates of QM as a fact of life, in spite of its seemingly uncomfortable coexistence
with special relativity, or we can postulate that QM is not complete: that there
was more information available for the description of the two-particle system at
the time it was created, but that we didn’t know that information, perhaps because it
cannot be known in principle, or perhaps because QM is currently incomplete.

In 1964 John Bell proposed a mechanism to test for the existence of these hidden
variables, and he developed his famous inequality as the basis for such a test. He
showed that if the inequality were ever not satisfied, then it would be impossible to have
a local hidden variable theory that accounted for the spin experiment.

Note only local hidden variable interpretations are under fire.

Three years later, Franson published a paper showing that the timing constraints in
this experiment were not adequate to confirm that locality was violated. Aspect
measured the time delays between detections of photon pairs. The critical time delay
is that between when a polarizer angle is changed and when this affects the statistics of
detecting photon pairs. Aspect estimated this time based on the speed of a photon
and the distance between the polarizers and the detectors. Quantum mechanics does
not allow making assumptions about where a particle is between detections.
We cannot know when a particle traverses a polarizer unless we detect the
particle at the polarizer.
#47 Stephen R. Diamond says:
8 Apr 2012, 12:04 am
I’d say that the strong plausibility of the success of MWI and weak plausibility of the failure of Bell’s Theorem adds up to there being reasonable doubt over the existence of randomness. And if there’s no randomness, there’s nothing for naturalists to worry about.

It wouldn’t seem to follow that the mere existence of “reasonable doubt” about randomness gives naturalists (defined as being determinists) nothing to worry about!

I don’t think the MWI eliminates randomness, in that its explanations are ineluctably probabilistic. While the MWI posits universal deterministic, insofar as its scientific–that is, explains observations, it remains probabilistic. Why a given experimenter obtained the data actually before him is not given a deterministic explanation. This point seems to confuse many MWI-proponents.
#48 joseph says:
8 Apr 2012, 1:55 am
You mean in effect MWI tries to substitute:

the result is random

For:

you end up in a random universe, where the result is said to have been determined
#49 Stephen R. Diamond says:
8 Apr 2012, 9:18 pm
I think you have the idea. Perhaps:

Substituting the result’s (*inescapable*) randomness for a random universe is a good way to put it.

I don’t see how the result is determined in the Copenhagen Interpretation. The interpretations agree that the result is ineluctably random. CI attributes this to the universe’s inherent randomness; MWI makes it a random result of a nominally deterministic universe.
#50 joseph says:
9 Apr 2012, 2:13 am
I don’t see how the result is determined in the Copenhagen Interpretation.

Just a fun thought that popped up, CI and MWI determine which choices are possible, and which are impossible. Other interpretations seem to include retrocasuality… Are CI and MWI compatabilist?

I will continue my ponderation.
#51 Dov Henis says:
9 Apr 2012, 3:37 am
Again, IMO:

There cannot be randomness in an evolving universe, in any evolving system.

The quantum mechanics of every process is its evolution.
Quantum mechanics are mechanisms, possible or probable or actual mechanisms of natural selection.
Evolution Is The Quantum Mechanics Of Natural Selection.
Natural selection is:
Mass formats attain temporary augmented energy constraint in their successive generations, with energy drained from other mass formats, to temporarily postpone, survive, the reversion of their own constitutional mass to the pool of cosmic energy fueling the galactic clusters expansion.

Dov Henis
(comments from 22nd century)
#52 joseph says:
9 Apr 2012, 6:44 am
Would you mind re-writing that in as plain English as possible? Or if somebody else understoood that could they attempt to explain it to me?
#53 Dov Henis says:
9 Apr 2012, 7:49 am
Joseph,

Please read slowly,
think,
consider yourself a mass format, just one of many many mass formats,
read again, and ponder…

Rgrds,
Dov
#54 joseph says:
9 Apr 2012, 11:12 am
Ok, so for mass format you an arrangement of mass?
Temporary augmented energy constraints?
Limits in energy, which are augmented temporarily?
By augmented you mean the constraints are made stronger? More constraining?
By evolution I guess you just mean progression?
With energy drained from other mass formats; couldn’t you just say energy is transfered but conserved?
Then you say something about mass breaking down, I guess you are referencing the heat death of the universe.

So you seem to be saying mass eventually breaks down, but some forms of mass postpones this at the cost of other forms of mass, the decay of which I’d have to guess is accelerated.

It seems dressed up in as much non-standard terminology as possible, and verges on mysticism, and seems to be deliberately obscure. However, I’d like to give you the benefit of doubt, so if I’ve got this wrong and you can put it in plainer english, or someone else can, I’d be glad to hear it.
#55 Stephen R. Diamond says:
10 Apr 2012, 1:22 pm
Are CI and MWI compatabilist?

I don’t think there’s any simple relationship between interpretations of qm and compatibilism vs. determinism.

Determinism, the term, means something different in philosophy of mind and in metaphysics. In philosophy of mind, it means that free will doesn’t exist, regardless of whether reality is stochastic or deterministic.

I’m a determinist in philosophy of mind and a probabilist in metaphysics. (I feel a lot more confident of the first position than the second; some days, I wake up a metaphysical determinist, but I’ve never seriously entertained free will since early adolescence.
#56 Stephen R. Diamond says:
11 Apr 2012, 4:24 pm
Joseph,

Here’s an issue for your: Should the verdict of the best science be presumed true for purposes of metaphysics? I’m inclined to say yes; in fact, I’m tempted to say the yes answer is the best definition of “physicalism.” Put crudely, science has gotten it wrong, but “pure reason” has failed much more often and much more dramatically. In this mood, at least, I’m inclined to say the universe is at bottom stochastic rather than deterministic. (Thus, theories like MWI are a form of anti-empirical rationalism because they deny the straightforward conclusion of physical experimentation that matter supplies only probabilities.)

But here’s an interesting potential counter-example. Newton and Leibnitz argued about whether space was absolute or relational. (http://tinyurl.com/48dxal4) I think–but haven’t studied it enough to be sure–that Leibnitz got the better of the argument. (There’s a danger of hindsight bias.) But physics probably couldn’t have been developed initially except on the assumption of absolute space. After physicists had apparently vindicated Newton empirically, should metaphysicians of the time have accepted absolute space even though (if) Leibnitz had refuted absolute space logically.

I’m inclined to say yes, they should have gone with absolute space. Despite being ultimately misleading, the empirical evidence of an actual science based on absolute space argued in its favor more strongly than Leibnitz’s seemingly decisive reasoning argued against it. What do you think?
#57 Dov Henis says:
12 Apr 2012, 12:10 am
Re Origin And Essence Of Considerations And Discussions:
——————————————————–

Consciousness is a brainchild, and the brain is a progeny of mono-cells communities evolution:

Origin Of Brained-Nerved Organisms

From http://universe-life.com/2012/02/03/universe-energy-mass-life-compilation/

Evolution of life, of mass formats self-replication:

- RNA nucleotides Genes (organisms) to RNA and DNA genomes (organisms) to mono-cellular to multicellular organisms.

- Individual mono-cells to cooperative mono-cells communities, “cultures”.

- Mono-cells cultures to neural systems, then to nerved multicellular organisms.

Dov Henis
(comments from 22nd century)
#58 joseph says:
14 Apr 2012, 2:01 am
Sorry it’s taken me a while to respond Stephen R.Diamond, it was an interesting question.
Should Science be considered true for the purposes of metaphysics? I guess not, as even science doesn’t consider science “true”. However for pragmatic discussion it is very useful to put ideas into a falsifiable form, based on empirical measurement. It is sometimes very difficult to logically falsify scientific theories, as sometimes assumptions are taken for granted as true (I think for example the kalam cosmological argument takes advantage of a few assumptions, which are natural from a human perspective). Another problem with logically constructing a metaphysical framework seems to be there are a number of logically consistent possibilities, knowing how to weight any of them is a challenge. If you use logic alone you seem to expose yourself to the risk of telling the universe what it is, rather than listening.

That said I any metaphysical philosophy without logic is doomed from inception. I like the Quinean idea that empirical results check a logical system (a hypothesis) as a whole. It seems a waste of time (all be it a pleasant one at times) to discuss non-falsifiable ideas.

Over all I’d say truth is something we approach (I haven’t decided yet if it’s an inclusive or exclusive limit), as step by step we gain insight into which of our models of the universe have less predicative power. Metaphysics to me seems to bite of a great deal more than it can chew and attempts to skip ahead to an “ultimate truth”, without doing the groundwork. This charge could be levelled at quantum interpretations and string theory, I keenly await any unique predictions any of them might make.
#59 Peter Hurford (author) says:
19 Jun 2012, 2:37 am
Has it really been nearly half a year since I earnestly engaged with this topic? Wow. Time flies.

However, don’t let this mean that I haven’t been studying the issue. It’s just that the nitty-gritty of QM is a recipe for one major ice cream headache.

I don’t really have anything of personal substance to report, but I did today stumble upon a pretty good introductory series to Many Worlds:
* “If quantum mechanics says everything is random, then how can it also be the most accurate theory ever?”
* Entanglement omnibus
* How is it that Bell’s Theorem proves that there are no “hidden variables” in quantum mechanics? How do we know that God really does play dice with the universe?
* How do bell pairs entangled particles behave experimentally?
* Which is a better approach to quantum mechanics: Copenhagen or Many Worlds?
* What is a “measurement” in quantum mechanics?
* According to the Many Worlds Interpretation, every event creates new universes. Where does the energy and matter for the new universes come from?

More updates as my slow study of tons of complicated material warrants.
#60 Peter Hurford (author) says:
22 Jun 2012, 5:00 pm
Another massive resource on Quantum Mechanics is “The Everett FAQ”. The FAQ not only provides an answer to the Ockham’s Razor objection to Many Worlds, but provides some evidence for it as superior to other interpretations, with an argument from authority, an argument from failures of other interpretations, an argument from retrodiction, and an argument from prediction.

The FAQ also talks about the handling of randomness, saying that Many-Worlds is “deterministic on the objective universal level [and] indeterministic on the subjective level”. In “Q25 Why am I in this world and not another? Why does the universe appear random?” there is a more direct answer:

Consider, for a moment, this analogy:
Suppose Fred has his brain divided in two and transplanted into two different cloned bodies (this is a gedanken operation! [*]). Let’s further suppose that each half-brain regenerates to full functionality and call the resultant individuals Fred-Left and Fred-Right. Fred-Left can ask, why did I end up as Fred-Left? Similarly Fred-Right can ask, why did I end up as Fred-Right? The only answer possible is that there was no reason. From Fred’s point of view it is a subjectively random choice which individual “Fred” ends up as. To the surgeon the whole process is deterministic. To both the Freds it seems random.

Same with many-worlds. There was no reason “why” you ended up in this world, rather than another – you end up in all the quantum worlds. It is a subjectively random choice, an artefact of your brain and consciousness being split, along with the rest of the world, that makes our experiences seem random. The universe is, in effect, performing umpteen split-brain operations on us all the time. The randomness apparent in nature is a consequence of the continual splitting into mutually unobservable worlds.

(See “How do probabilities emerge within many-worlds?” for how the subjective randomness is moderated by the usual probabilistic laws of QM.)

[*] Split brain experiments were performed on epileptic patients (severing the corpus callosum, one of the pathways connecting the cerebral hemispheres, moderated epileptic attacks). Complete hemispherical separation was discontinued when testing of the patients revealed the presence of two distinct consciousnesses in the same skull. So this analogy is only partly imaginary.
#61 Peter Hurford (author) says:
22 Jun 2012, 5:48 pm
Can MWI Be Falsified?

Joseph (1/22): I am cautious enough not to rule it out, but I am one of those sad individuals who is hoping to live long enough to see another paradigm shift in physics…I’m hoping string theory produces something falsifiable.

Quantum Mechanics actually is falsifiable, even if the specifically Many-Worlds Interpretation may not be, and this isn’t a problem for Many-Worlds.

However, I actually think that the Many-Worlds Interpretation (MWI) of Quantum Mechanics (QM) may be falsifiable, because MWI says QM will be linear (worlds can interfere with each other but not communicate with each other) and local (no communication faster than the speed of light). It also says gravity exists in particles, not waves.

So find gravity waves, faster-than-light communication, and/or non-linearity and you have falsified MWI.
#62 Peter Hurford (author) says:
22 Jun 2012, 5:49 pm
Finally, Half a Year Later, A Long-Anticipated Answer to Bryan. Ta Da!

Bryan (1/20 3:49am): Some of the QM materials I’ve read refer to all “possible” worlds. But if a god is possible then we have universes that feature a god or gods. How do we know this isn’t one of them?

The worlds in MWI do not refer to all possible worlds, so this wouldn’t be an issue. It also wouldn’t be an issue if your concept of God was logically impossible. MWI itself does not do anything to rule out a deity, however.

~

And if we have different outcomes from identical starting points then we have done exactly what we set out to avoid–break the (deterministic) laws of physics.

We haven’t done away with determinism, because these worlds still evolved from a deterministic wave-function. What we have done, however, is done away with subjective determinism because you, as an observer, cannot predict which world you will find yourself in prior to the measurement.

And, returning to the parallel of the double slit experiment, do observations obliterate some number of the many worlds?

As far as I can tell, observations do not obliterate worlds. In fact, in MWI, the “observation” does nothing except place the observer into multiple states.

~

Bryan (1/20 4:01am): One more point. Many worlds also appears to present a problem for logic.

Joe blinks at time t

Joe does not blink at time t

We have a contradiction if existent universes featuring these conditions are isomorphic at time t-1, based on the notion that Joe and Joe are Joe at the same time and in the same sense.

This is not a logical contradiction because you are referring to two different “Joe”s in two different worlds.
#63 Stephen R. Diamond says:
22 Jun 2012, 6:30 pm
“deterministic on the objective universal level [and] indeterministic on the subjective level”

MWI calls whatever MWI can explain “objective”; what it can’t, “subjective.” In which world you find yourself is as an objective outcome.

[Incidentally, in my last post above, I was in an excessively empiricist mood.]
#64 Peter Hurford (author) says:
22 Jun 2012, 10:53 pm
Stephen: MWI calls whatever MWI can explain “objective”; what it can’t, “subjective.” In which world you find yourself is as an objective outcome.

I’m not sure I follow.

~

Stephen (4/11): In this mood, at least, I’m inclined to say the universe is at bottom stochastic rather than deterministic. (Thus, theories like MWI are a form of anti-empirical rationalism because they deny the straightforward conclusion of physical experimentation that matter supplies only probabilities.)

Why are you inclined to say the universe is at bottom stochastic? How do you think MWI fails? What do you think of the merits of MWI above the others (see above comments)? What interpretation of QM do you prefer and why?
#65 Peter Hurford (author) says:
22 Jun 2012, 11:00 pm
Bryan (3/9): As for me, I’d have appreciated either a sketch of the time symmetric hypothesis or a link describing the view along the lines you’re thinking. I went here to find out about it:
http://arxiv.org/html/physics/9812021v2

That sounds like a very interesting and promising approach. Do you have any more information on this theory so I can further pursue and research it?

~

If TS theory explains the same phenomena as MW then it is preferable on the basis of Occam’s Razor to MW.

Not necessarily — recall our previous conversation on Occam’s Razor. TS theory would have to explain the same phenomena with less (or more simple) underlying laws as well. Or, TS theory could have equally simple laws, yet have less worlds.

The Everret FAQ has a pretty good explanation of this as well:

Q21 Does many-worlds violate Ockham’s Razor? [...] Many-worlds is viewed as unnecessarily complex, by some, by requiring the existence of a multiplicity of worlds to explain what we see, at any time, in just one world.

This is to mistake what is meant by “complex”. Here’s an example. Analysis of starlight reveals that starlight is very similar to faint sunlight, both with spectroscopic absorption and emission lines. Assuming the universality of physical law we are led to conclude that other stars and worlds are scattered, in great numbers, across the cosmos. The theory that “the stars are distant suns” is the simplest theory and so to be preferred by Ockham’s Razor to other geocentric theories.

Similarly many-worlds is the simplest and most economical quantum theory because it proposes that same laws of physics apply to animate observers as has been observed for inanimate objects. The multiplicity of worlds predicted by the theory is not a weakness of many-worlds, any more than the multiplicity of stars are for astronomers, since the non-interacting worlds emerge from a simpler theory.
#66 Stephen R. Diamond says:
23 Jun 2012, 4:27 pm
Peter,

I’m not sure I follow [how MWI pushes randomness under the rug].

Let’s look at the analogy on offer:

Suppose Fred has his brain divided in two and transplanted into two different cloned bodies (this is a gedanken operation! [*]). Let’s further suppose that each half-brain regenerates to full functionality and call the resultant individuals Fred-Left and Fred-Right. Fred-Left can ask, why did I end up as Fred-Left? Similarly Fred-Right can ask, why did I end up as Fred-Right? The only answer possible is that there was no reason. From Fred’s point of view it is a subjectively random choice which individual “Fred” ends up as. To the surgeon the whole process is deterministic. To both the Freds it seems random.

Same with many-worlds. There was no reason “why” you ended up in this world, rather than another – you end up in all the quantum worlds. It is a subjectively random choice, an artefact of your brain and consciousness being split, along with the rest of the world, that makes our experiences seem random. The universe is, in effect, performing umpteen split-brain operations on us all the time. The randomness apparent in nature is a consequence of the continual splitting into mutually unobservable worlds.

What’s subjective in Fred’s case is Left Fred’s lack of knowledge of why he’s Left Fred; analogously for Right Fred. There’s no explanatory gap. Nothing is truly left to random. The surgeon can understand why Left Fred is Left Fred and Right Fred is Right Fred, and he can convey this information to both.

So, in the Fred experiment if I’m Fred and I wake up Right Fred, there’s an explanation of why: I grew out of original Fred’s left hemisphere.

But in MWI, there’s no explanation for why I got the result I got and not an equally probable one. Nor is there any machinery for ever providing such an explanation. An ineluctable randomness remains and is dismissed as “subjective” without any principled justification.
#67 Peter Hurford (author) says:
23 Jun 2012, 4:37 pm
Stephen: But in MWI, there’s no explanation for why I got the result I got and not an equally probable one. Nor is there any machinery for ever providing such an explanation. An ineluctable randomness remains and is dismissed as “subjective” without any principled justification.

I’m still not sure I follow. On MWI, you don’t get one result or the other result. You get both results. You’re just not aware of getting both results because you find yourself in only one world, and don’t have access to the other Stephen that found himself in the other world.

Stephen-LEFT sees result-LEFT and wonders why he didn’t see result-RIGHT. Likewise, Stephen-RIGHT sees result-RIGHT and wonders why he didn’t see result-LEFT.

Unfortunately for us, everything in the analogy is the same except we just don’t have a transworld surgeon that can see this from an “objective”-point-of-view and explain the process to us. Indeed, such a transworld surgeon would be impossible on MWI.
#68 Stephen R. Diamond says:
23 Jun 2012, 4:54 pm
Why are you inclined to say the universe is at bottom stochastic? How do you think MWI fails? What do you think of the merits of MWI above the others (see above comments)? What interpretation of QM do you prefer and why?

I recently characterized my mood when I wrote this as excessively empiricist–meaning I gave too much weight to surface conclusions from qm. At the moment I’m inclined to think the universe must be deterministic. To be honest about my plausibility function, I’d have to say I’m close to 50-50 on the question. I want to read an essay you cited on why quantum mechanics impels a stochastic view of the universe, as I haven’t seen the question addressed quite so explicitly before.

I’ll tell you what weighs in each direction. In favor of a stochastic universe, you have the precision of qm’s results. If qm were a model with variables missing, it seems that this would imply that qm is only approximate, that it misses the mark somewhere, which I don’t think has been found.

On the side of a deterministic universe, as I interpret probability, I don’t think probabilities can apply (speaking conceptually) without underlying deterministic relations. [I don't want to try to defend this yet.] This line of thinking favors a hidden variables theory, I suppose.

While I’m partial toward Bohm but see some merit in even the Copenhagen Interpretation (as a decision to stay close to the empirical facts without venturing a true theory), I’m hostile to MWI because I think it just pushes the issues concerning determinism underground (by dismissing the randomness MWI sanctions as “subjective”).

Whether you see the universe as deterministic or stochastic seems to have little direct effect on anything outside of philosophy. Even physics doesn’t seem to need to figure it out, at least not just yet. But, I’m not sure it’s been noticed, the question could have deep implications for cosmology, where MWI and stochastic approaches lead to the same conclusion that “our” Big Bang was a chance occurrence. Not so if the universe is truly deterministic per Bohm.

As I understand the Bell Inequalities, they stand for the impracticability of local theories rather than deterministic theories as such. I take the main lesson of qm to be that the world is more richly interconnected than simple causality allows.
#69 Stephen R. Diamond says:
23 Jun 2012, 5:08 pm
I’m still not sure I follow. On MWI, you don’t get one result or the other result. You get both results. You’re just not aware of getting both results because you find yourself in only one world, and don’t have access to the other Stephen that found himself in the other world.

The term “result,” at least as I’m using it, refers to outcomes of experiments. So what we’re talking about isn’t what happens “under MWI” but in actual experiments. In an experiment, you get one result or the other. MWI explains that all the results are also occurring, but that characterization doesn’t change the fact that I got one particular result and the theory lacks the machinery to explain why I did.

Unfortunately for us, everything in the analogy is the same except we just don’t have a transworld surgeon that can see this from an “objective”-point-of-view and explain the process to us. Indeed, such a transworld surgeon would be impossible on MWI.

Which is just to say, the theory lacks any explanation that could, even in principle, explain the particular result that I got.
#70 Peter Hurford (author) says:
23 Jun 2012, 7:01 pm
I want to read an essay you cited on why quantum mechanics impels a stochastic view of the universe, as I haven’t seen the question addressed quite so explicitly before.

Which one?

~

I’ll tell you what weighs in each direction. In favor of a stochastic universe, you have the precision of qm’s results. If qm were a model with variables missing, it seems that this would imply that qm is only approximate, that it misses the mark somewhere, which I don’t think has been found.

Can’t the universe be deterministic without requiring hidden variables (MWI)?

~

As I understand the Bell Inequalities, they stand for the impracticability of local theories rather than deterministic theories as such.

I think that’s a slight misunderstanding of Bell’s Theorem. With the words of caution that I’m not adequately trained in physics (let alone QM!), my understanding of Bell’s Theorem is that it means that all hidden variables must be non-local (require faster-than-light communication).

Bell’s Theorem doesn’t rule out local theorems without hidden variables, which basically means MWI (pretty much the only local, non-hidden-variable interpretation out there). This makes MWI the most viable way to preserve locality in light of Bell’s Theorem, which is good, because locality seems likely to be correct.

The only way I can think of to have a non-local theory is to invoke retrocausality, which would be the approach of Time-Symmetric interpretations or Richard Carrier’s interpretation. I’m sympathetic to these interpretations.

~

but see some merit in even the Copenhagen Interpretation (as a decision to stay close to the empirical facts without venturing a true theory)

Copenhagen Interpretation isn’t any closer to the empirical facts than other interpretations. Rather, I’d suggest it’s further because it gives up locality, gives up linearity, often has a “consciousness causes collapse” view, and requires a different physical law for observers than non-observers.

What I think you would prefer is to accept the experimental results, but remain agnostic as to the interpretation. This was my view until I found indication that MWI was a superior interpretation.

~

I’m hostile to MWI because I think it just pushes the issues concerning determinism underground (by dismissing the randomness MWI sanctions as “subjective”).

In an experiment, you get one result or the other. MWI explains that all the results are also occurring, but that characterization doesn’t change the fact that I got one particular result and the theory lacks the machinery to explain why I did.

It does explain the result by saying that you’re point-of-view is of the result in this world, and a different Stephen in a different world saw a different result.

You’re right it doesn’t explain why Stephen-Left is Stephen-Left and Stephen-Right is Stephen-Right, but I see this as not being damaging to the theory. Rather, it’s analogous to the Fred-Surgeon example.

Likewise, I find it similar to asking the question “Why am I Peter, instead of Stephen?”

~

But, I’m not sure it’s been noticed, the question could have deep implications for cosmology, where MWI and stochastic approaches lead to the same conclusion that “our” Big Bang was a chance occurrence. Not so if the universe is truly deterministic per Bohm.

…Or if QM overthrows the extensively common assumption that “everything that begins to exist needs a cause”.
#71 Stephen R. Diamond says:
24 Jun 2012, 12:43 am
It does explain the result by saying that you’re point-of-view is of the result in this world, and a different Stephen in a different world saw a different result.

Well, let’s be precise. If the result is *this* Stephen’s observation Y, this isn’t explained by saying that another Stephen observed X. What you’re explaining is how the theory allows Stephen to observe Y. You’re showing that the observation of Y is consistent with the theory because of what others are observing. It squares the definite outcome, Y, with a theory that predicts all other possible outcomes; but that isn’t to explain why this experiment produces the particular outcome it does produce.

You’re right it doesn’t explain why Stephen-Left is Stephen-Left and Stephen-Right is Stephen-Right, but I see this as not being damaging to the theory. Rather, it’s analogous to the Fred-Surgeon example.

The question is how damaging is it that the theory can’t explain this. It makes my being Stephen Left a brute fact about the world, without possible explanation. Fred-Surgeon doesn’t provide a model for this because there’s a ready explanation for why each is each.

Perhaps the following makes this clearer. Imagine assigning each Stephen version a unique number. Now, *this* Stephen has an imaginary number, being a distinct being, but I can’t know which one it is. Maybe that doesn’t sound so bad. But then consider that I can’t imagine (within the theory) any possible explanation for why “I” turn out to be Stephen 101 and not Stephen 99 or some other Stephen. This is a brute fact about the world, but it’s not even clear what kind of fact it is.

Likewise, I find it similar to asking the question “Why am I Peter, instead of Stephen?”

Maybe that analogy will take us somewhere. At least, it might help me understand why you don’t see any problem with not being able even to formulate a kind of an explanation of why I’m Stephen 101. You say it’s like asking why you’re you and not me.

But what’s hard about explaining why you’re you? Is it hard to explain why my dog is Buster Brown and my neighbor’s dog is Toby? Why isn’t Buster Brown Toby? The answer seems obvious, doesn’t it. They’re just separate organisms. Asking why you’re not me can seem harder, I think, because you imagine that I’m my consciousness and you want to know why this consciousness is associated with this body and not another. The question comes with dualist baggage. The question isn’t really hard, is it? You’re Peter because you’re the organism that was named Peter.

The question about whether “I” am Stephen 101 or Stephen 99 similarly is a question about which organism observed “this” experiment. MWI’s inability to explain why I, the experimenter, am Stephen 101 is indeed as *bad* as if we couldn’t explain why you’re Peter. (Unless I’m missing something about the why-are-you-not-me “puzzle,” in which case I’d really like to understand it).

Copenhagen Interpretation isn’t any closer to the empirical facts than other interpretations. Rather, I’d suggest it’s further because it gives up locality, gives up linearity, often has a “consciousness causes collapse” view, and requires a different physical law for observers than non-observers.

That’s treating it as a theory. What I’m saying is it stays close to the data as opposed to theoretical insights.
#72 Peter Hurford (author) says:
24 Jun 2012, 1:18 am
The question is how damaging is it that the theory can’t explain this. It makes my being Stephen Left a brute fact about the world, without possible explanation. Fred-Surgeon doesn’t provide a model for this because there’s a ready explanation for why each is each.

I’m arguing that the Fred example is analogous to what actually happens with Many-Worlds. In the Fred example, you have Fred split into two Freds based on surgery. In Many-Worlds, you have Stephen split into two Stephens based on decoherence.

For example, in Shrodinger’s Cat, there is a cat in a box and a geiger counter that emits a lethal dose of cyanide if radioactive decay is detected. Radioactive decay starts out in a superposition of (decay / no decay), which then interacts with the geiger counter, which goes into a superposition of (detected / not detected), which interacts with the cyanide dispenser which goes into a superposition of (dispensed / not dispensed), which interacts with the cat who goes into a superposition of (dead / alive). Eventually, Stephen opens the box and interacts with the cat and enters into a superposition of (Stephen noticing the cat is dead / Stephen noticing the cat is dead).

What is the crucial difference between the case of Fred-Left wondering why he is not Fred-Right and Stephen-noticing-the-cat-is-dead wondering why he is not Stephen-noticing-the-cat-is-dead?
#73 Stephen R. Diamond says:
24 Jun 2012, 1:19 am
The only way I can think of to have a non-local theory is to invoke retrocausality, which would be the approach of Time-Symmetric interpretations or Richard Carrier’s interpretation.

Bohmian physicists currently harbor non-local theories without retrocausality, don’t they?
#74 Peter Hurford (author) says:
24 Jun 2012, 1:24 am
Bohmian physicists currently harbor non-local theories without retrocausality, don’t they?

Yep. But non-locality requires some basis for genuine faster-than-light interactions, which haven’t been found yet and seem impossible under current understandings of relativity. Retrocausality is still non-local, but doesn’t involve faster-than-light communication because the interaction is just backwards through time. Retrocausality is still not quite mainstream, but is supported by the well-received Feynman-Stueckelberg Interpretation of antimatter.
#75 Stephen R. Diamond says:
24 Jun 2012, 1:30 am
What is the crucial difference between the case of Fred-Left wondering why he is not Fred-Right and Stephen-noticing-the-cat-is-dead wondering why he is not Stephen-noticing-the-cat-is-dead?

That there really is an explanation for the Fred distinctions but not for the Stephen distinctions. Fred left is distinguished from Fred right by prior history; but the history of the various Stephens is the same.

Can you explain why there’s a problem with explaining why Peter isn’t Stephen? I think that might simplify the problem.
#76 Stephen R. Diamond says:
24 Jun 2012, 4:50 pm
The only way I can think of to have a non-local theory is to invoke retrocausality, which would be the approach of Time-Symmetric interpretations or Richard Carrier’s interpretation.

I think this is backwards. Carrier invokes retro-causality to propose a local theory. Non-local theories don’t require superluminal transmission (or retrocausality).

And MWI, at least as expounded by Yudkowsky, is nonlocal. Spatially disconnected events are treated as a single outcome. (So, MWI can’t claim the advantage of being a local theory–which I agree would be advantageous but doesn’t seem obtainable.)
#77 Stephen R. Diamond says:
24 Jun 2012, 6:20 pm
…Or if QM overthrows the extensively common assumption that “everything that begins to exist needs a cause”.

Do you really see that as at all probable? If the universe is fundamentally stochastic, I think the upshot would be a redefinition of causality as probabilistic. (I recall reading a book years ago by Suppes sketching a model of probabilistic causality.) Just as we now struggle to rethink “belief” as something coming in degrees, we would have to think the same way about causation.

Nothing occurs without cause would become “nothing occurs without its having some finite probability.” This is still infinitely different from things just happen for no reason–which predicts utter chaos. [What it does rule out is as purely subjective interpretation of probability--or a purely logical interpretation, which I favor. Probabilities would have to be admitted as part of the basic ontology of the universe.]
#78 Stephen R. Diamond says:
25 Jun 2012, 3:33 pm
SRD:As I understand the Bell Inequalities, they stand for the impracticability of local theories rather than deterministic theories as such.

PH:I think that’s a slight misunderstanding of Bell’s Theorem. With the words of caution that I’m not adequately trained in physics (let alone QM!), my understanding of Bell’s Theorem is that it means that all hidden variables must be non-local (require faster-than-light communication).

Bell’s Theorem doesn’t rule out local theorems without hidden variables, which basically means MWI (pretty much the only local, non-hidden-variable interpretation out there). This makes MWI the most viable way to preserve locality in light of Bell’s Theorem, which is good, because locality seems likely to be correct.

I don’t think that’s right. Joseph’s post and the associated article explains it clearly:

http://www.greatplay.net/essays/continuing-comments-on-randomness-and-naturalism#comment-7578
#79 joseph says:
25 Jun 2012, 11:43 pm
Quick note on retrocausality and non-locality:

http://adsabs.harvard.edu/abs/2006AIPC..863..340B

As far as I know:

>c = backwards time
c = time stands still
c, as I understand it very strong gravitational fields, space itself moving >c (hyperinflation) allow it.

Bohmians aknowledge the “pilot wave” exceeds c, and so imply retrocausality, though what exactly the pilot wave is/represents seems a big topic.

MWI and CI both seem to beg the question “What maketh a measurer”?
#80 joseph says:
26 Jun 2012, 12:48 am
And it seems you must sacrifoce either realism or locality upon the Altar of Bell’s Inequalities.
#81 joseph says:
26 Jun 2012, 1:13 am
Ok, my mobile seemed to botch that, so try again, using a curséd App.

Yes, I don’t think the issue is whether QM is falsiable, it clearly is. Rather the issue is, are QM Interpretations falsifiable.

Bell Inequalities and Leggett Inequalities suggest certain characteristics are mutually exclusive.

As for Gravity being particles, well any wave, even loooong lollopy ones like radiowaves, can be represented as particles. Likewise even hard, big buckminsterfullerenes (promise will check the spelling later) can produce interference patterns, and thus be considered waves. So it seems any particle can be modelled as a wave, and vice versa. So I’m not at all sure if the prediction of “Gravitons” is unique to MWI. With “linearity” is this theoretically falsifiable or currently falsifiable?

>c = backwards time

c = time stands still

<c = time as we experience it

Exceeding c, is not, totally prohibited by Einstein's theories . As I understand it, c can be exceeded in very strong gravitational fields, if space itself is moving (hyperinflation). Some string theories predict a tachyon/tachyons.

Bohmians aknowledge the “pilot wave” exceeds c, and so imply retrocausality, though what exactly the pilot wave is/represents seems a big topic.
MWI and CI both seem to beg the question “What maketh a measurer”?
#82 joseph says:
26 Jun 2012, 1:57 am
http://www.nature.com/news/2011/110405/full/news.2011.210.html
#83 Stephen R. Diamond says:
26 Jun 2012, 2:30 pm
Joseph,

And it seems you must sacrifoce either realism or locality upon the Altar of Bell’s Inequalities.

Could you explain what you mean by sacrificing realism?

As far as I know:

>c = backwards time
c = time stands still
c, as I understand it very strong gravitational fields, space itself moving >c (hyperinflation) allow it.

Bohmians aknowledge the “pilot wave” exceeds c, and so imply retrocausality, though what exactly the pilot wave is/represents seems a big topic.

Do Bohmians still push pilot waves? Didn’t Bohm himself move to a “holographic” view, which would treat spatially separated entanglements as single entities?

I’m not sure that Bohm believed superliminal transmission implies retrocausality. I mention it because you seem unsure, too.
#84 joseph says:
27 Jun 2012, 12:00 am
Sure, by sacrificing realism I mean that non-hidden variable theories (CI, MWI) assume that if a measurement is not taken then what would be measured (i.e. the position of an electron, the polarity of a photon) does not have a definite value. So for example a decaying potassium atom releases beta-radiation, a positron, in this case if memory serves. According to non-hidden variable theories, if the position and momentum of this positron is not measured then the positron has no trajectory, it is released in all directions at once, at a range of different velocities. Non-hidden variable theories assume that unless a measurement is taken, a definite value does not exist. Or in a somewhat rhetorical way, if no-one looked at the moon it would cease to exist in a particular place.

The question of whether non-locality implies retrocasuation and what Bohmian’s in general believe is confusing the proverbial hell out of me.

As far as I can understand the simple way of understanding the consequences of travelling at, or faster than, the speed of light on the flow of time seem to apply in Lorentz Invariant and Minkowski space-time.

It turns out Bohmian Mechanics is pretty hard to formulate in Lorentz Invariant space-time.

It is a lot easier to formulate in a version of space-time called Lorentz Ether Theory. Yes, writing the word Ether scares me, then again Æther is worse. From what little I can understand Karl Popper seemed to like this idea, and it leads to the idea of a ‘Holographic’ universe, a universe with an undetectable (again, that is contentious) preferred reference frame. Bohmians seem to somehow avoid retrocasuality by their interpretation of space-time, which they argue is as valid as the interpretation generally used by Special Relativity, and experimentally indistinguishable.

None of this allows faster than light transmission of signals, information etc by statiscal measurements, damned if I understand why.

A quick quote from Bell:

[The usual quantum] paradoxes are simply disposed of by the 1953 theory of Bohm, leaving as the question, the question of Lorentz Invariance. So one of my missions in life is to get people to see that if they want to talk about the problems of Quantum Mechanics – the real problems of Quantum Mechanics – they must be talking about Lorentz Invariance

As far as I can tell the use of Lorentz Ether (shudder) theory has not meant the pilot wave has been abandoned.

My own understanding is in Bohmian mechanics a particle is, well a particle, and the pilot wave is the path determined by the interaction with every other particle in the universe. If any physicists can tell me why that’s not even wrong, I’d be grateful.

Some notes on ideas as to how Bohmian Mechanics could be falsified:

- Inflationary cosmology as a probe of primordial quantum mechanics A. Valentini (2008).

- De Broglie-Bohm prediction of quantum violations for cosmological super-Hubble modes, A. Valentini (2008).

- Astrophysical and cosmological tests of quantum theory, A. Valentini (2007).

A lot of the information has come from this website, in the various lectures:

http://www.tcm.phy.cam.ac.uk/~mdt26/pilot_waves.html

It seems fairly biased towards Bohmian mechanics, but reasonably unlikely to cause an aneurysm, which is pretty good for anything written by a physicist about QM.

A picture of an electron cloud:

http://en.dogeno.us/wp-content/uploads/2009/09/atomweb.jpg

The story I get with most frequency about Bell Inequalities is that Local Hidden Variable theories are ruled out. This seems to get confused by other terminology and ontological preference.

he showed that if the inequality were ever not satisfied, then it would be impossible to have
a local hidden variable theory that accounted for the spin experiment.

Those who like MWI and CI say Bell Inequalities rule out Hidden Variable theories.

Those who dislike MWI and/or CI say Bell Inequalities rule out Local theories.

Those who wish to confuse me use the term counter factual definiteness .

So MWI and CI are allowed as they are non-hidden variable theories. I have yet to read all of the MWI faq, that Peter Hurford provided.
#85 joseph says:
27 Jun 2012, 12:02 am
Geez I may hate Apps, but they do let me write huge posts, check the spelling (no auto spell checker), and get the formatting right.
#86 Stephen R. Diamond says:
27 Jun 2012, 2:49 am
My own understanding is in Bohmian mechanics a particle is, well a particle, and the pilot wave is the path determined by the interaction with every other particle in the universe. If any physicists can tell me why that’s not even wrong, I’d be grateful.

The universe or our light cone? My guess, you really mean the former. If I’m right, that might be falsified should the universe prove to be infinite in extent, as now seems to me not unlikely.

Your summary is very useful. I’ve found your sense of confusion a good index of actual incoherence, and the “hair-splitting” in which Bohmians seem to engage discourages me about the prospects of hidden variables and tilts me back toward a stochastic interpretation (since I think MWI “not even wrong” for reasons I’ve already discussed). I mean, if you’ve got to go back to the ether and determinate frames of reference to save a theory, forget it.

In fairness to MWI, though, I think it is realist. At least it is as Yudkowsky expounds it. There’s nothing but the continuous unfolding of the wave function.
#87 joseph says:
27 Jun 2012, 4:31 am
Yes indeed, I meant the whole universe rather than our light cone. I think the idea would be if all matter came from a singularity then it is all entangled, or all shares a history.

Some notes on the Ether:

*it may be an invisible, pink unicorn.

*it may be logically required, or satisy Ockham’s Razor in the same way as multiple undetectable universes are supposed to. I prefer one invisible, logically coherent, pink unicorn to many.

*it may be falsifiable, this idea seems to start flame wars on physics forums

*it may not be necessary; the Stanford Philosophical Encyclopædia mentions a few examples of, at least, attempts to reconcile Bohmian Mechanics with Lorentz Invariance. I highly suspect some sort of retrocausality is the cost.

*I see certain parallels among the ideas of Ether, Zero used as a number, and the “nothing” that Physicists propose we are expanding into. I could at best only provide an adumbration this.

Some notes on MWI:

* I haven’t read Eliezer Yud(somethingsomethingsomething)ski’s account of MWI, but I have to wonder who, or what, plays the role of measurer? My understanding of MWI is that when a measurement is taken, that is the point when alternative universes arise. One of my biggest conceptual problems with MWI, and CI, is the status given to a measurer, or, alternatively decoherence, which seems linked to measurement. Wikipedia confused me with the following:

in particular there is no (indeterministic and irreversible) wavefunction collapse associated with measurement. The phenomena associated with measurement are claimed to be explained by decoherence, which occurs when states interact with the environment producing entanglement, repeatedly splitting the universe into mutually unobservable alternate histories—distinct universes within a greater multiverse.

Perhaps another way of putting this is the dividing line between the classical and the quantum.

*Is MWI in support of realism. Well it votes “No”, on Counter Factual Definiteness, about which Wiki, purveyor of truthiness says:

n some interpretations of quantum mechanics, counterfactual definiteness (CFD) is the ability to speak meaningfully of the definiteness of the results of measurements that have not been performed (i.e. the ability to assume the existence of objects, and properties of objects, even when they have not been measured), which is at odds with superdeterminism.

Emphasis mine.

By stochastic interpretation do you mean something like Einstein’s preferred Enselmble Interpretation, or a non-hidden variables approach.

I’ve found your sense of confusion a good index of actual incoherence

Thankyou! I hope it’s that, as the other option is my own limited intellect!

The fact that there are many types of Bohmians worries me that we might have a “no true Scotsman” situation, on the other hand MWI seems an umbrella that harbours many views, although, unlike the Bohmians, they’re a large enough group to actually schism.
#88 joseph says:
27 Jun 2012, 5:31 am
http://philosophyfaculty.ucsd.edu/faculty/wuthrich/teaching/2009_146/Lecture12_Putnam.pdf

You may find this interesting, I did note that measurement is not responsible for causing the collapse of the probability wave in MWI. I still need to answer what causes decoherence.

GRW is:

http://en.wikipedia.org/wiki/Ghirardi%E2%80%93Rimini%E2%80%93Weber_theory
#89 joseph says:
27 Jun 2012, 6:08 am
Wikipedia also provides the following:

MWI is a realist, deterministic, local theory, akin to classical physics (including the theory of relativity), at the expense of losing counterfactual definiteness. MWI achieves this by removing wavefunction collapse, which is indeterministic and non-local, from the deterministic and local equations of quantum theory.

As you can tell I’m having a hard time understanding how an interpretation can be regarded as Realist and concurrently reject Counter-Factual Definiteness.

If wikipedia provides a clue, perhaps it’s somewhere here:

Everett noticed that the unitary, deterministic dynamics alone decreed that after an observation is made each element of the quantum superposition of the combined subject-object wavefunction contains two “relative states”: a “collapsed” object state and an associated observer who has observed the same collapsed outcome; what the observer sees and the state of the object have become correlated by the act of measurement or observation. The subsequent evolution of each pair of relative subject-object states proceeds with complete indifference as to the presence or absence of the other elements, as if wavefunction collapse has occurred, which has the consequence that later observations are always consistent with the earlier observations. Thus the appearance of the object’s wavefunction’s collapse has emerged from the unitary, deterministic theory itself.

I think a connected objection is the one you made:

Can MWI be said to be deterministic?

Stanford Philosophical Encyclopædia shows that this is contentious:

“. In the words of Steane 1999, “It is no use to say that the [Schrödinger] cat is
‘really’ both alive and dead when every experimental test yields unambiguously the result that the cat is either alive or dead.”

Just as MWI answers determinism with something like “everything that is not impossible happens”, it answers realism with “everything that is not impossible is real”. It seems both a funny sort of determinism and a funny sort of realism.
#90 joseph says:
27 Jun 2012, 1:04 pm
So finally looked at the MWI FAQ, and I made some notes:

The idea of “measurement”, and it’s effects seem a little confused. Firstly, yes measurements are at least the focii of decoherence, when universes diverge.

More detail on Weinberg’s views can be found in _Dreams of a Final
Theory_ or _Life in the Universe_ Scientific American (October 1994),
the latter where Weinberg says about quantum theory:
“The final approach is to take the Schrodinger equation seriously [..description of the measurement process..] In this way, a measurement causes the history of the universe for practical purposes to diverge into different non-interfering tracks, one for each possible value of the measured quantity. [...] I prefer this last approach”

Again later it is noted:

That each measurement causes a decomposition or decoherence of the universal wavefunction into non-interacting and mostly non-interfering branches, histories or worlds.

My concern, which seems to have been ill founded, was that a “measurement” may have required a “measurer”. Later it is made explicit that a measurer is not required:

1.

A measurement, by this definition, does not require the presence of an
conscious observer, only of irreversible processes.

2.

Decoherence refers to the loss of coherency or absence of interference effects between the elements of the superposition

3.

The precise moment/location of the split is not sharply defined due to the subjective nature of irreversibility, but can be considered complete when much more than kT of energy has been released in an uncontrolled fashion into the environment. At this stage the event has become irreversible.

However, later, answering another question, it says:

Another popular view is that irreversible processes trigger collapse. Certainly wavefunctions appear to collapse whenever irreversible processes are involved. And most macroscopic, day-to-day events are irreversible. The problem is, as with positing observers as a cause of collapse, that any irreversible process is composed of a large number of sub-processes that are each individually reversible.

There seems to be a conflict here. The “environment” can be said to make a measurement through decoherence when a generally macroscopic, irreversible process interacts with another process, then becoming entangled with it. Yet the large irreversible event is made of smaller, reversible processes.

This makes provokes 3 thoughts:

1. If the environment itself can cause decoherence, in MWI do any superpositions exist within a single universe?

2. How are these events irreversible?

3. If the whole universe has a sort of wave function, what causes decoherence of this universal wave function?

Another point that bothers me is:

Some popular accounts describe the
other worlds as splitting off into other, orthogonal, dimensions. These dimensions are the dimensions of Hilbert space, not the more familiar space-time dimensions.

I am uncomfortable with this use of Hilbert Space (as I am with ether). Though an alternative solution is encouraged later.

Whenever the amplification of a quantum-scale interaction effects the mass distribution and hence space-time curvature the resultant decoherence can be regarded as splitting the local space-time manifold into discrete sheets.

Though I confess ignorance as to whether it’s possible, or if the mechanism requires some sort of simultaneous i.e. superluminal splitting of all space-time everywhere, it seems better than Hilbert Space.

The answers regarding Ockham’s Razor and Conservation of Energy allayed some of my fears. Though I wonder if the universe started with a finite amount of energy if there’s a lower limit to how much energy is required by a split. Maybe that represents an event with zero probability.

I think, Peter Hurford, that when you say Gravity exists as particles you mean Gravity is quantised. From what I understand so far, that is a prediction of Quantum Field Theory, which isn’t the exclusive domain of the MWI.
#91 joseph says:
28 Jun 2012, 1:59 am
As a sort of pasticcio of various interpretations’ attitudes towards Realism:

Q: Does the Moon exist when not watched?

A:
C.I.
No.

M.W.I.
Yes and no.

de Broglie-Bohm
Yes.

*it may be logically required, or satisy Ockham’s Razor in the same way as multiple undetectable universes are supposed to. I prefer one invisible, logically coherent, pink unicorn to many.

This was unfair of me. Multiple universes seem to arise from one principle, so it seems one invisible, pink unicorn or the other. Not one versus many.

I apologise and retract my statement.
#92 Stephen R. Diamond says:
28 Jun 2012, 3:04 pm
I’m not yet sure, but I don’t think C.I. implies the moon doesn’t exist when it isn’t watched. One confusion is the vast number of positions that can be termed “antirealist.” Antirealist with respect to what? is the question. The confusion occurs, it seems to me, because in the philosophy of science antirealism means antirealism about truth. The antirealism of C.I. seems to be about particular physical parameters.

Consider my (provisional) interpretation of quantum mechanics, which may be compatible with CI:

1. Physical properties are dispositional: they consist of propensities. Then, probability is a basic fact of nature.

2. The only way to describe the propensities of basic units of matter is by the probability of obtaining various macroscopic observations.

Certainly matter exists when it isn’t observed. (As shown by the evolution of the wave function over time.) But we’re limited in how to describe it. We can describe it only by reference to the probabilities of various outcomes in experiments. But it isn’t that only the outcomes of experiments are real! It is that if we want to refer to the states of matter, when unobserved, we can do so only by reference to observations we could obtain.
#93 Stephen R. Diamond says:
28 Jun 2012, 3:08 pm
It is that if we want to refer to the states of matter, when unobserved, we can do so only by reference to observations we could obtain.

Even absent actual observations, the probabilities of obtaining observations are the properties of matter
#94 Stephen R. Diamond says:
28 Jun 2012, 5:13 pm
Why do probabilities seem like they may not be properly materialist? I think it’s a matter of what’s really required to exclude “purpose” from ultimate science. Probabilities seem purposive; in Yudkowsky talk, they seem like “mind projections.”

So the question is the definition of purpose. Here’s a suggestion: Purpose means a functional relationship (in the math sense) from future outcomes on past events; causality means a functional relationship from past outcomes on future events. In purpose, there’s a one to many relationship between outcomes and their predecessors in time; in causality, there’s a one-to-many relationship between a cause and multiple future effects.

Whether a shortcoming or virtue, this view would demonize retrocausality rather than indeterminism. (I’m allowing that causality is redefined in terms of probabilistic propensities.)
#95 joseph says:
29 Jun 2012, 3:25 am
I’m not yet sure, but I don’t think C.I. implies the moon doesn’t exist when it isn’t watched. One confusion is the vast number of positions that can be termed “antirealist.” Antirealist with respect to what?

The comment about the moon is perhaps somewhat a hyperbole, borrowed from Mr.Einstein. For the most part (I’d estimate 19 out of 20) Copenhagen interpretations are labelled “anti-realist”.

The Copenhagen interpretation itself is hardly monolithic. There are some odd variants that consider themselves realist, you have to dig a little to find them. On the other hand Heisenberg seems to have had a notably more positivistic outlook than his mentor, Bohr. But then if 3 people read Bohr there will be 5 opinions about what he meant.

So what do I mean when I say the Copenhagen interpretation is “anti-realist”?

I think it comes down to my understanding of counter-factual definiteness, rejected by the CI. I mentioned it before, and it comes down to the sentence I’ve emboldened:

In some interpretations of quantum mechanics, counterfactual definiteness (CFD) is the ability to speak meaningfully of the definiteness of the results of measurements that have not been performed (i.e. the ability to assume the existence of objects, and properties of objects, even when they have not been measured), which is at odds with superdeterminism. A macroscopic example of CFD would be the assumption—without measurement—that a ball, thrown into the air, will return to the Earth due to gravity.

Some notes on Realism and the Copenhagen Interpretation, which I feel illustrate the respect in which the CI is anti-realist:

Wikipedia
1.

according to the interpretation, the interaction of an observer or apparatus that is external to the quantum system is the cause of wave function collapse, thus according to Heisenberg “reality is in the observations, not in the electron”

2.

Many physicists and philosophers have objected to the Copenhagen interpretation, both on the grounds that it is non-deterministic and that it includes an undefined measurement process that converts probability functions into non-probabilistic measurements. Einstein’s comments “I, at any rate, am convinced that He (God) does not throw dice.” and “Do you really think the moon isn’t there if you aren’t looking at it?” exemplify this. Bohr, in response, said “Einstein, don’t tell God what to do”[citation needed].

3.

E. T. Jaynes, from a Bayesian point of view, pointed out probability is a measure of a human’s information about the physical world. Quantum mechanics under the Copenhagen Interpretation interpreted probability as a physical phenomenon, which is what Jaynes called a Mind Projection Fallacy.

Stanford Encyclopædia of Philosophy:

1.

Also after the EPR paper Bohr spoke about Heisenberg’s “indeterminacy relation” as indicating the ontological consequences of his claim that kinematic and dynamic variables are ill-defined unless they refer to an experimental outcome. Earlier he had often called it Heisenberg’s “uncertainty relation”,
as if it were a question of a merely epistemological limitation.

2.

Bohr thought of the atom as real. Atoms are neither heuristic nor
logical constructions. A couple of times he emphasized this directly
using arguments from experiments in a very similar way to Ian Hacking
and Nancy Cartwright much later. What he did not believe was that the
quantum mechanical formalism was true in the sense that it gave us a literal (‘pictorial’) rather than a symbolic representation of the quantum world. It makes much sense to characterize Bohr in modern terms as an entity realist who opposes theory realism (Folse 1987). It is because of the imaginary quantities in quantum mechanics (where the commutation rule for canonically
conjugate variable, p and q introduces Planck’s
constant into the formalism by pq − qp = ih/2π) that quantum mechanics does not give us a ‘pictorial’ representation of the world. Neither does the theory of relativity, Bohr argued, provide us with a literal representation, since the velocity of light is introduced with a factor of i in the definition of the fourth coordinate in a four-dimensional manifold (CC, p. 86 and p. 105). Instead these theories can only be used symbolically to predict observations under well-defined conditions. Thus Bohr was an antirealist or an instrumentalist when it comes to theories.

3.

Quantum systems are not vizualizable because their states cannot be tracked down in space and time as classical systems’. The reason is, according to Bohr, that a quantum system has no definite kinematical or dynamical state prior to any measurement.

Your interpretation does seem like the Ensemble (a word which until 5 minutes ago, I could have sworn had a second, silent, “l”) Interpretation). Have you had a look at it?:

http://en.wikipedia.org/wiki/Ensemble_interpretation

It’s very pragmatic, and I am drawn to it. One comment that H.Nikolić (I think) made on Physics forums was something like:

“Yes, but don’t you want to know how the magician performs the trick?”

He was referring to the fact that this sort of interpretation makes no commitment to what happens in the case of the single – atom/electron/photo etc. – it is hidden variables agnostic, by design.

As for being useable, non-aneurysm inducing, and pragmatic it’s wonderful.

The whole retrocausality thing is rather confusing, as a lot of restrictions (regarding information transfer and such), seem to exist, but when asked to explain why Physicists resort to equations.

Of course, given my employment, it would be quite bad for business, if people could put their dead cats in boxs and immediately proclaim there was a probability the poor cat was alive instead of dead. Instead of calling for medical assistance they would call perjaps a statistician, for mathematical assistance. (I stole this joke from somewhere – citation needed).
#96 Stephen R. Diamond says:
2 Jul 2012, 12:13 am
the ability to assume the existence of objects, and properties of objects, even when they have not been measured

“Realism,” then, depends upon what you consider a proper property of objects. If you take the “interpretation” I ventured, it’s realist because the properties are measurement propensities. But someone else would call the objects of measurement (mass, momentum, and the like) the “properties,” in which case it’s antirealist.

He was referring to the fact that this sort of interpretation makes no commitment to what happens in the case of the single – atom/electron/photo etc. – it is hidden variables agnostic, by design.

On the ensemble interpretation. I have trouble with the rejection of individual probabilities.
#97 joseph says:
2 Jul 2012, 3:34 am
“Realism,” then, depends upon what you consider a proper property of objects.

Surely the object’s very existence:

the ability to assume the existence of objects,

Is a property sacrosanct to any type of Realism?

I think to make a judgement as to whether the Diamond Interpretation was realist, or not, I would need to know if you considered the superposition state an ontological or epistemological construct. If ontological, how is the measurement problem resolved?
#98 Stephen R. Diamond says:
2 Jul 2012, 1:28 pm
Surely the object’s very existence:

Doesn’t doubt about the object’s existence come into play because the interpreter believes objects are constituted by their properties (which I agree with) AND their properties are the “observables” (which I reject).

would need to know if you considered the superposition state an ontological or epistemological construct. If ontological, how is the measurement problem resolved?

“Superposition” is a metaphor for the reality that matter consists of a bundle of propensities. Superposition is, on this account I suppose, ontological. What is epistemological is “collapse,” which merely means a measurement is made.

The “wave function” describes the propensities of *particles*.
#99 Stephen R. Diamond says:
2 Jul 2012, 1:36 pm
how is the measurement problem resolved?

A measurement is an expression of a particle’s propensities.

The problem of measurement arises, I think, because the waves are conceived as really existing rather than expressing the propensities of particles.
#100 Stephen R. Diamond says:
2 Jul 2012, 4:06 pm
To clarify further on the measurement problem: The straightforward solution to the Schroedinger cat problem is that the cat is itself a measuring instrument. (But I don’t know if the cat is viewed as much of a problem these days.)
#101 Stephen R. Diamond says:
2 Jul 2012, 6:10 pm
Joseph and any others interested,

I’ve made a change in the text of “Another Refutation of Compatibilism” as a result of Joseph’s questions. It makes the argument clearer. (It was unclear enough before that I forgot a vital condition.)

http://tinyurl.com/cdl69lk
#102 Stephen R. Diamond says:
7 Jul 2012, 11:25 pm
SRD: I’ve made a change in the text of “Another Refutation of Compatibilism” as a result of Joseph’s questions. It makes the argument clearer. (It was unclear enough before that I forgot a vital condition.)

I have elaborated and (I hope) improved this argument in “Reflexive prediction, determinism, and the impossibility of free will.” (http://juridicalcoherence.blogspot.com/2012/07/1012-reflexive-prediction-determinism.html)
#103 joseph says:
8 Jul 2012, 2:47 am
Thanks Stephen,
Having a busy few days…be sure to comment soon.
#104 joseph says:
14 Jul 2012, 4:38 am
So, you seem to want your interpretation to have hidden
variables. That is your answer to Schrodinger’s Cat said the
cat itself was a measurer. I would then ask, what prevents an
atom from being a measurer? If the answer is nothing, then
the wave function is merely an epistemological limit, and so
there are hidden variables. If the answer is something like a
cat is a macroscopic system, and a atom is not, then I would
ask where, and why, we draw a line.

The other clue that you favour a hidden variables approach is, I think, that you’ve said conceiving of waves as actually existing is a proplem, yet that is exactly what non-hidden variables interpretation (including Bohr’s) do.

I am then confused why you say:

Superposition is, on this account I suppose, ontological

Sorry if that wasn’t the direct quote, I’ve upgraded (supposedly) operating system and the damn thing refuses to copy from the comments section. If A.I. does ever arise I don’t fear it will be evil the way Muehlhauser does, but I highly suspect it will be a wanker.

Anyway, I am missing something here, on one hand you’ve said superposition is ontological(which I take to mean actually exists), on the other you’ve said viewing a wave (which I took to mean wave function) as existing was a problem.

I find propensities a difficult word as both an objects actual state can be described as a propensity (a propensity for certain actions given certain unknowns about it’s surroundings), and a superposition state can be described as a propensity.
#105 Stephen R. Diamond says:
14 Jul 2012, 4:11 pm
Hi Joseph,

It’s about time. :)

If the answer is something like a cat is a macroscopic system, and a atom is not, then I would ask where, and why, we draw a line.

What if we define “macroscopic” as a limit. An object approaches this limit as it approaches infinite size (I don’t know whether bracketing relativity here is justifiable.) The asymptote, fortunately, comes at fairly small sizes. A cat is almost “macroscopic,” whereas an atom is far from macroscopic.

on one hand you’ve said superposition is ontological(which I take to mean actually exists), on the other you’ve said viewing a wave (which I took to mean wave function) as existing was a problem

I think I had an erroneous definition of superposition in mind. Wikipedia says it’s wave state. Based only on that, if I reject waves, I suppose I must call superposition epistemological. I was thinking “superposition” meant a state inherently indeterminate with respect to classical variables (e.g., momentum, position). By that (apparently false definition) I think is ontological.

I find propensities a difficult word as both an objects actual state can be described as a propensity (a propensity for certain actions given certain unknowns about it’s surroundings), and a superposition state can be described as a propensity.

Are you saying we should find a different word or that the concept is equivocal or ambiguous? The problem you notice for “propensities” is a carryover from the same issues for probabilities (which are use to describe propensities).

I got the term from Karl Popper’s interpretation of probability, according to which probabilities are real dispositions. I don’t think they’re necessarily real dispositions, but they are in qm.
#106 joseph says:
15 Jul 2012, 12:19 am
it’s about time. :)

Too true! I was beginning to think the work would never end.

If we define the limit as infinity aren’t we left with the problem that both the cat and the atom are infinitely smaller than our limit?
What would we then make of larger molecules (buckminsterfullerenes, mRNA, DNA, proteins)?

Personally I have a tendency to think of the wave function as epistemological, to my understanding this represents a hidden variables interpretation. I think though the MWI could claim it views the wave function as ontological as it represents the proportions of universes in which the varying states are observed, and yet MWI is non-hidden variables.

Yes, at the moment the concept of “propensities” is ambiguous to me, though it seems a serviceable enough word. That is I could say an atom with precisely known position, and (magically) a precisely known momentum has a propensity to travel in direction z, or I could say an atom with a position of x (+/- delta x), a momentum of y (+/- delta y) has a propensity for being at position x, a propensity for having momentum y and thus a propensity to travel in direction z.

One view is that of a hidden variables interpretation, and allows a classically deterministic view, the other is of a non-hidden variables view and at most allows you to decide determinism in terms of what is forbidden, and what is likely.
#107 joseph says:
15 Jul 2012, 8:16 am
So I have to post this here:

http://www.smbc-comics.com/index.php?db=comics&id=2672#comic
#108 Stephen R. Diamond says:
17 Jul 2012, 4:39 pm
If we define the limit as infinity aren’t we left with the problem that both the cat and the atom are infinitely smaller than our limit?
What would we then make of larger molecules (buckminsterfullerenes, mRNA, DNA, proteins)?

If we define degree of macroscopicness as a variable ranging from 0 (with a point particle) to 1 (with an infinite size–leaving for science the measure of “size,” whether mass or whatever) a cat could still approach a value of 1. That’s what I was referring to in saying that the function has an early asymptote.

Very large molecules are probably in between. They can be used to make measurements but not very reliably. (Measurement realizes propensities but doesn’t in itself change them. So the question is a practical one.)
#109 Stephen R. Diamond says:
19 Jul 2012, 1:34 am
Joseph,

Here’s a puzzle you might enjoy. Robert Wiblin at “Overcoming Bias” argues that Pascal’s Wager makes logical sense. “Life after death for Pascal’s Wager?” – http://tinyurl.com/7dpv3c6

Try to solve the paradox before looking at my comments. :)
#110 joseph says:
20 Jul 2012, 3:20 am
I think I understand what your saying (I had to read a little about asymptotes), but what principle, or reason, would mean the Cat is never in a superposition, but an atom (which is no longer modelled as a point particle) is sometimes in superposition?

I have a preference for saying superposition is epistemological, and both the cat and the atom are “self measuring” i.e. there are hidden variables.

When you say measurement realises propensities it seems to indicate that they were previously, unreal, no?

I’m having a look at the puzzle in question over some rather nice coffee and bacon.
#111 Stephen R. Diamond says:
20 Jul 2012, 3:52 am
I think I understand what your saying (I had to read a little about asymptotes), but what principle, or reason, would mean the Cat is never in a superposition, but an atom (which is no longer modelled as a point particle) is sometimes in superposition?

Well, the cat would, it seems to me, be in superposition some extraordinarily small fraction of the time. Perhaps having the cat ever be in superposition is what seems to create the problem, but all it means it that the cat has properties at these times that violate the laws of macroscopic nature.

When you say measurement realises propensities it seems to indicate that they were previously, unreal, no?

The propensities exist all the time; the macroscopic properties are created by measurement, hence realized.

I have a preference for saying superposition is epistemological, and both the cat and the atom are “self measuring” i.e. there are hidden variables.

What evidence would be required to convince you that chance is a fundamental property of matter?
#112 joseph says:
20 Jul 2012, 4:27 am
Brief response re “what evidence?”, I’d be most satisfied by one of the Quantum Interpretations predicting something the others could not, and the other interpretations being falsified.

Though the more dedicated followers of particular interpretations seem to think this can, in theory, be done, I have doubts.

I would definitely be able to concur that for large numbers of physical entities, that are fundamentally impossible to “measure” without having a significant effect upon, epistemologically chance is a fundamental property of matter.
#113 joseph says:
20 Jul 2012, 4:50 am
How are propensities different (ontologically) from macroscopic properties? By my understanding (or preferred interpretation, they are the same, the only difference being an epistemological one, which is easily understandable given the relative sizes of what is being measured (an atom), what is being used to perform the”measurement” (a photon), and the “measurer” (macroscopic system).

Yes, you’ve hit the nail on the head with the cat, why would there be “macroscopic laws of nature” and “quantum laws of nature”; why not, like relativity, one set of laws (i.e. quantum) which become more significant as scale (space-time) approaches planck dimensions (?).
#114 Stephen R. Diamond says:
20 Jul 2012, 4:59 am
I would definitely be able to concur that for large numbers of physical entities, that are fundamentally impossible to “measure” without having a significant effect upon, epistemologically chance is a fundamental property of matter.

If you believe in hidden variables, then chance isn’t fundamental. I get what you mean, but it wasn’t the question. :) That is, it seems to me that the only reason to believe in hidden variables is not to be satisfied with objective chances as fundamental in physical explanation, as “metaphysically fundamental.” You must think it’s simpler to postulate hidden variables than to postulate objective chances, despite the lack of direct evidence for hidden variables. If *in principle* we can’t verify or refute hidden variables observationally, isn’t the scientific course to reject them? Don’t hidden variables become rather like the ether of old?
#115 Stephen R. Diamond says:
20 Jul 2012, 5:04 am
How are propensities different (ontologically) from macroscopic properties? By my understanding (or preferred interpretation, they are the same, the only difference being an epistemological one, which is easily understandable given the relative sizes of what is being measured (an atom), what is being used to perform the”measurement” (a photon), and the “measurer” (macroscopic system).

Propensities really exist, whereas macroscopic properties don’t. (As you recognize in the following paragraph.) However, propensities are always expressed in macroscopic properties–which are measurements. It seems a bit Kantian. The propensity as like a “thing in itself.” You can know it indirectly by the measurements it entails, but you can’t otherwise say exactly what it is.
#116 joseph says:
20 Jul 2012, 5:15 am
A serious question, no doubt.

I think there are 2 paths:

1/ My doubts about the different Quantum Interpretations being experimentally indistinguishable are born out. Then non-hidden variable interpretations and hidden variable interpretations are equally non-falsifiable. I can reject all interpretations (this is why I have previously said I have to be a quantum agnostic at this stage), which is something like the “shut up and do the math(s)” approach.
Non-hidden variables assume every microscopic system takes on a superposition state if not measured (or unreachable many worlds), hidden variables assumes things have properties beyondt the ability of my equipment to measure. Hidden variable theories are not alone in having untestable assumptions.

This is emotionally unfulfilling, hence why I say I have a preference for bohmian mechanics (followed by the ensemble interpretation, then the time symmetric interpretation, then MWI).

2/ They can (in my ever shortening lifetime) be falsified. Yippee Kai Yay! Whatever the outcome may be….
#117 joseph says:
20 Jul 2012, 5:41 am
I would parse this:

propensities really exist, whereas macroscopic properties don’t

Propensities and macroscopic properties are the same. Macroscopic quantities are merely known to a degree of precision, and the effect of any measurement is so insignificant, that they are intuitive to humans. Propensities are on such a scale that the degree of imprecision, and the effect of measurement so significant, that they are no longer intuitive to humans. Thus why it is so hard to draw a distinct line between macroscopic and quantum is laid out as a difficulty in defining what humanity finds intuitive or not.

I would agree with your statement that we can only know things in an indirect fashion, and add that all interaction results in changes at some level.
#118 Stephen R. Diamond says:
20 Jul 2012, 9:49 pm
I have a preference for bohmian mechanics

What kind of preference is this: aesthetic, epistemic, moral? The way I look at it, the only kind of preference that’s justified is one based on its being more plausibly true–that is, that you think it is more likely to be true. Do you find the whole substructure of Bohmian mechanics more plausible than the existence of ontological chances? (Can you stomach the rebirth of the ether?–when Leibnitz already made the decisive metaphysical arguments for a relational view of space centuries ago.)

I think the real test might be cosmology, in other words, testing two lines of speculation against each other. Let’s say that “fine tuning” is substantiated as a real cosmological problem and the problem seems solvable only by assuming multiple universes and using anthropic reasoning. To provide for sufficiently variegated universes, we may need genuine chance. Genuine chance is also what allows Krause to play his trick of showing why something exists instead of almost nothing. On the other hand, the periodic universe seems particularly compatible with strict determinism, hence hidden variables. It seems only in cosmology that it really becomes important to know whether chance is real (or only epistemic).

I don’t think I agree, however, that hidden variables contains assumptions less testable than a propensity (ontologically stochastic) interpretation. If you interpret the superposition as a bundle of propensities, the existence of superpositions means primarily that the probabilities obtained in experiments are properties at the level of reality you’re describing it, whereas hidden variables requires positing a whole hidden domain that seems to call for experiments that can never be done.
#119 joseph says:
20 Jul 2012, 11:44 pm
Aesthetic, I have found no experimental justification for it, or any quantum interpretation. I find superposition being ontological a big problem, and linked to that anti-realist interpretations difficult to understand.
As for stomaching the ether, if all it is is an absolute reference frame, then I see it as a mathematic construct, similar to zero. If it (still) makes predictions that are falsified, then no, I will gladly abandon the idea. If Bohmian mechanics can be formulated in accord with Lorentz Invariance, then I can abandon the idea of an absolute reference fairly, without any impact on the veracity of Bohmian mechanics.

As for testing. Ok, so non-hidden variables posit that when something is unobserved it enters a position state. How do you test that? Remember any observation you make is said to destroy the superposition state.
#120 joseph says:
20 Jul 2012, 11:46 pm
Enters a position state=enters a superposition state
#121 Stephen R. Diamond says:
21 Jul 2012, 12:40 am
As for testing. Ok, so non-hidden variables posit that when something is unobserved it enters a superposition state. How do you test that? Remember any observation you make is said to destroy the superposition state.

You test it by showing that the same state produces various outcomes and produces them in proportion to the propensities the theory assigns. A superposition is just a bundle of propensities, which are demonstrated by realizing one or the other variously.
#122 joseph says:
21 Jul 2012, 1:04 am
That result could equally be explained by an epistemological superposition (a bundle of states you can’t differentiate due to constraints on measurements), or an ontological superposition (things that seem to make no logical sense, such as a photon travelling through both slits in a double slit experiment, if unobserved. Or a particle both existing and not existing, if not observed).

You’ve said previously if you rejected waves, you’d reject superposition as ontological, if you do that, then you’re left with a hidden variables interpretation, or MWI.
#123 Stephen R. Diamond says:
21 Jul 2012, 2:27 am
You’ve said previously if you rejected waves, you’d reject superposition as ontological, if you do that, then you’re left with a hidden variables interpretation, or MWI.

I don’t really know whether it would be more accurate to say that I “reject” superposition or that I re-interpret it. I was hoping you’d tell me. I think I can “save the phenomenon” without going realist on waves. A superposition is just a bundle of propensities. If you don’t think that makes sense, please tell me.

That result could equally be explained by an epistemological superposition (a bundle of states you can’t differentiate due to constraints on measurements), or an ontological superposition (things that seem to make no logical sense, such as a photon travelling through both slits in a double slit experiment, if unobserved. Or a particle both existing and not existing, if not observed).

Sure. But a particle both existing and not existing violates the laws of logic, so that’s a very, very deep change. A particle traveling through both slits is also blatantly illogical. Again, it’s possible that logic is wrong, but that’s a very extreme conclusion, to be avoided if at all possible. I think constraints on measurement is your best card and the one you really intend to play.

So what’s simpler or involves the least fraught assumptions: that unmeasurable hidden variables exist or propensities exist? Well, how did relativity theory handle a similar conflict. Why do physicists believe space and time really are relative. The limitations on what can happen in relativity also pertain to the possibility of measurements. Why not say instead that space and time really are absolute, that absolute simultaneity really exists, and that relativity pertains only to the limitations on our ability to measure, such as our inability to exceed the speed of light when transmitting information?

I think science holds a presumption that anything that exists can be measured. If Bohmian physicists accepted your view that their constructs can’t be measured, I think they’d concede defeat. Introducing entities that aren’t measurable in principle is almost as bad as accepting logical contradictions (such as a particle existing and not existing–despite that appealing to my Hegelian tendencies).
#124 joseph says:
21 Jul 2012, 3:54 am
Again a brief answer first, bohmian mechanics is very upfront about being a hidden variables interpretation, so I think they’d have to be ok with the idea of immeasurables.
#125 joseph says:
21 Jul 2012, 6:02 am
From wiki:

the main challenge facing propensity
theories is to say exactly what propensity means. And then,
of course, to show that propensity thus defined has the
required properties. At present, unfortunately, none of the
well-recognised accounts of propensity comes close to meeting
this challenge

I too, am trying to get a handle on the word propensity,
though it would seem I am unlikely to succeed where my
betters have failed.

For me the crucial bit of information would be:

Does a propensity reflect an ontological superposition or an
epistemological superposition.

Schrodinger’s cat has a propensity for being alive, (O.5) and
a propensity for being dead (0.5)*, does this mean the cat is
in a jumbled up alive-dead state? If the answer is yes, even
if only for a short time due to the size of system a cat
represents, then I think we bow to wave interpretation of
reality, and the unmeasured, single photon logically can, and
does, go through both slits if unmeasured.

If the propensties are merely an epistemological construct,
and the same as saying “the probability the cat is alive is
0.5, and dead 0.5″, then we are dealing with a hidden
variables interpretation or MWI, the lone photon is dealt
with as a particle and goes through a single slit even when
unmeasured.

So what’s simpler or involves the least
fraught assumptions: that hidden variables exist or
propensities exist

Well if propensities are epistemological, it’s a false
dilemna.

If they are ontological then they seem logically on a par.

I have a question for physicists I should post on a forum:

If hyper-expansion represents space moving at faster than
light speeds, and particles were interacting, and entangled
before the process began, does that represent superluminal
transfer of information and retrocasuality according to
relativity?
#126 Stephen R. Diamond says:
21 Jul 2012, 1:57 pm
Again a brief answer first, bohmian mechanics is very upfront about being a hidden variables interpretation, so I think they’d have to be ok with the idea of immeasurables.

A question:

Does “hidden variables” imply that the variables will always remain hidden?
#127 Stephen R. Diamond says:
21 Jul 2012, 2:20 pm
On which wiki does the quotation appear?

Schrodinger’s cat has a propensity for being alive, (O.5) and
a propensity for being dead (0.5)*, does this mean the cat is
in a jumbled up alive-dead state? If the answer is yes, even
if only for a short time due to the size of system a cat
represents, then I think we bow to wave interpretation of
reality, and the unmeasured, single photon logically can, and
does, go through both slits if unmeasured.

On a propensity theory (I wasn’t aware the term was actually used–or had forgotten) as I’m thinking of it, the cat is always in a jumbled live-dead state. It’s just that the jumbledness is usually present to so small a degree as to be ignorable in practice. Why does that imply waves? It seems to me only to imply that reality is composed of propensities and our deterministic macro-reality is only an illusion of scale (to use your word). “Waves” are a way of talking about the propensities of particles.

If they are ontological then they seem logically on a par.

Propensities can be measured; hidden variables can’t. How is that logically on a par?

the main challenge facing propensity
theories is to say exactly what propensity means. And then,
of course, to show that propensity thus defined has the
required properties. At present, unfortunately, none of the
well-recognised accounts of propensity comes close to meeting
this challenge

This is the most worrisome part of propensities as I’m conceiving them, but the answer seems to be that after you’ve described their macroscopic effects, there’s nothing left to say about propensities. We’re limited to a language with macroscopic referents in describing propensities, and therefore, we can’t address “what” propensities are on their own terms, so to speak. (And that is something we normally expect of a theory.)
#128 Stephen R. Diamond says:
21 Jul 2012, 2:29 pm
“We’re limited to a language with macroscopic referents in describing propensities, and therefore, we can’t address “what” propensities are on their own terms, so to speak.”

This despite the fact that macroscopic properties don’t really exist. We’re defining the real in terms of the fictional, inverting ordinary analysis. A propensity can only be defined in terms of its macroscopic effects, yet it is not reducible to those effects.
#129 joseph says:
22 Jul 2012, 12:11 am
3rd time I’ve tried to write an answer….
Hidden variables are always hidden, though the degree to which they are hidden chnages.

Situation 1:
You measure the position and momentum of an atom by pinging it with a high frequency low wavelength photon (gamma). It’s position is well defined (little is hidden) it’s momentum is poorly defined (a lot is hidden)

Situation 2:
You measure the position and momentum of an atom by pinging it with a low frequency long wavelength photon (radiowave). It’s position is poorly defined (a lot is hidden) it’s momentum is well defined (a little is hidden).

Analogy 1:
You measure the position and momentum of a car, at night, which is driving on the motorway. You judge position by the headlights, you judge momentum by the length of light trails of the headlamps, divided by the shutter speed.

You take a photo with a camera with an exremely fast shutter speed. You are shown the photo (you cannot see the car directly), you can define position very well, you can only define momentum poorly (there is, to the human eye, no blur, no light trail).

Analogy 2:
You take a photo with a camera with an extremely slow shutter speed. You are shown the photo (you cannot see the car directly), you can define position very poorly, the car is a blur, you can however define momentum very well (there is a long light trail, the impact of minor errors in measurement is low).

It seems we do not readily say cars exist in superpositions of momentum and speed, ontologically speaking. Yet it seems as defensible as saying atoms and subatomic particles exist in superpositions (and I really do mean that neutrally).

Wich wiki? – Apologies, wikipedia, I looked up “Popper’s Quantum Interpretation”, wrongly believing I had previously read a so entitled article, and was redirected to an article called something like “Propensity Theory”, which seemed to apply none the less.

As for the cat being jumbled, well that could well be epistemic.

I want to correct what I said earlier, the difference (between behaviour on a quantum scale and behaviour on a macroscopic scale) is an illusion, rather than either behaviour on a quantum scale or behaviour on a macroscopic scale being an illusion. Sorry if that’s nit-picking.

Propensities can be measured yes, but the result varies (going back to my earlier point) according to method, therefore if propensities are ontological, rather than epistemic, does what is real change according to the way you phrase questions to the universe?

Why waves? – Merely because if a photon is modelled as a wave then it can logically go through both slits at the same time and superposition is logically able to be ontological.
#130 joseph says:
22 Jul 2012, 12:15 am
B#gger@tion!
I meant to also say all quantum interpretations can explain macroscopic phenomena, but in particular the C.I. and the Many Minds Interpretation (which I much, much earlier confused with M.W.I.) are particular unintuitive, to me (aesthetically sucky).
#131 Stephen R. Diamond says:
22 Jul 2012, 3:24 am
What I meant by hidden variables being forever hidden is whether Bohmians think their pilot waves, etc. will always remain hypothetical constructs or may in principle be measured.

It seems we do not readily say cars exist in superpositions of momentum and speed, ontologically speaking. Yet it seems as defensible as saying atoms and subatomic particles exist in superpositions …

I don’t think that can be right. One quick difference is that you can use two different cameras at the same time on the car and determine both velocity and momentum.

As for the cat being jumbled, well that could well be epistemic.

Of course. My point is only that there’s no problem with saying that the jumbling is ontological. Cat talk is usually inspired by wanting to show that ontological superposition is problematic.

does what is real change according to the way you phrase questions to the universe?

What is real is the propensity to be both. What changes is what propensity is realized.

I want to correct what I said earlier, the difference (between behaviour on a quantum scale and behaviour on a macroscopic scale) is an illusion, rather than either behaviour on a quantum scale or behaviour on a macroscopic scale being an illusion. Sorry if that’s nit-picking.

I think it’s very important–perhaps crucial. I stick with behavior on a macroscopic scale being illusions. On a macroscopic scale, it appears that determinism is true. An q.m. experimenter necessarily excepts the illusion. His measuring instruments are treated–must be treated–as classical objects. They give an unequivocal set of measurement results, without any trace of jumbledness being acknowledged. If the experimenter acknowledged the jumbledness, in his instruments, he wouldn’t know what to do with it.

Why waves? – Merely because if a photon is modelled as a wave then it can logically go through both slits at the same time and superposition is logically able to be ontological.

But the question is whether we need to conceive of the photon as going through both slits. We say the photons have wave properties because the distribution of photons shows wave interference effects. But all we need is to interpret the “waves” as being the mathematical rules determining the particles’ propensities.
#132 joseph says:
22 Jul 2012, 4:55 am
Jul10-12, 08:44 AM #47

Demystifier

Posts: 3,933

Blog Entries: 15

Recognitions: Science Advisor

For bhobba, mr. vodka, and bohm2: I don’t think that wave function in BM is more real than in standard QM.

In standard QM, one may (or may not) think of psi merely as a mathematical tool to compute the probability. Likewise, in BM one may (or may not) think of psi merely as a mathematical tool to compute the particle trajectories.

Both in standard-QM camp and in BM camp there are people who disagree on how “real” the wave function is. But in both camps, this question is NOT considered to be a crucial one.
__________________
Don’t listen to what I say; listen to what I mean.

This is the best answer I can find for what the pilot wave is/represents, the author is H.Nikolic, the thread’s url is:

http://www.physicsforums.com/showthread.php?t=619003&highlight=pilot+wave&page=3

I get the impression it’s a disputed issue.

As for the analogy being wrong because you could take 2 photos of the car, I can think of a few responses:

1/Theoretically, I suppose, you could hit the atom with 2 photons at the same time, reducing “hiddeness” further, I think practically you can’t due to difficulty controlling exactly when your photons leave you emitter.

2/ Even using both cameras there is still some uncertainty, thus some “hiddeness”.

I think according to any Quantum Interpretation, when a “measurement” is taken the measuring device is said to enter a relationship with what is measured, becoming part of the same quantum system.

Cat talk – I think it’s inspired by the fact it provides an intuitive demonstration that interpretation of superpositions as ontological is not realist. That’s not necessarily a logical problem. I heard one supporter of Bohm, in fact, saying that if Bohr had been a little snappier (and able to deliver one liners), when Einstein, to paraphrase, asked “is the moon not there when we aren’t watching it”, Bohr could’ve answered “If no ones watching it, it makes no difference”.

To me it seems that realism is an aesthetic preference.

Onto the photon, if the “jumbleness” is ontological, and not just mathematical formalism (which I’d label as an epistemological view), then the photon has no problem with going through both slits if unmeasured, it’s a bundle of propensities, some through slit A, some through slit B, neither is realised if not measured. Have I missed the point?

Or another answer is, no we don’t need to, we have no empirical commitment to any of the interpretations currently, we can choose either to pick one on the basis of which of our logical instincts are least offended, or wash our hands and stick to the maths.
#133 Stephen R. Diamond says:
22 Jul 2012, 4:35 pm
Joseph,

1.I think you’re plainly wrong about uncertainty with macroscopic objects. It’s a completely different effect than uncertainty about particles. Everyone knew about measurement effects before qm. The way qm differed is in there being an absolute barrier to precise prediction. What I’m not sure of is whether Bohmians accept the absoluteness of this barrier or consider the barrier only a stage in scientific progress.

The uniqueness of qm uncertainty (compared to macroscopic measurement error) is important because the discussion depends on comparing qm and macroscopic reality. If you think there’s no difference in principle in general, you can’t locate the real qm effects on macroscopic reality, which cause a real cat to be ever-so-slightly jumbled.

2. If it were just aesthetics, the conversation would be ridiculous. One should want a scientific theory to be true, not pretty. The only justification for aesthetics is as a guide to truth, which it is in a sense, in that plausibility is based on the same abstract features as beauty. (http://tinyurl.com/3e9fqcs) The moon is there when we don’t look at it because there’s no non-absurd explanation for why looking at it should make a difference. This makes the “explanation” prettier, but prettiness isn’t the point.

3. Some religious believers tacitly think they’re epistemically entitled to think what they want unless some logical contradiction is exposed. I have the feeling that’s your position on qm interpretations: pick the most “appealing” interpretation, and test it for consistency, logical and empirical. By that logic, to put it bluntly, one might still believe in geocentrism by making the orbits complicated enough–and the only criticism would be that it’s not a pretty view.
#134 Stephen R. Diamond says:
22 Jul 2012, 5:21 pm
Joseph,

I think that positing fundamental epistemic barriers (that don’t reduce to ontology) is antithetical to science. That’s why I’m led to guess that Bohmians think measurement of their deterministic hidden variables isn’t precluded in principle: that the imfeasibility is only a stage of scientific evolution.

That’s why I think Bohm’s is probably the only truly deterministic theory. MWI posits an absolute epistemic barrier to precise predictions, making its deterministic predictions fraudulent [why do I like that term?]

That’s apart from MWI’s coherence problems, as already discussed (those really being the stronger reason to reject it).

How much should be prefer a deterministic theory? How per se implausible is a theory that posits objective probabilities? Is it really that plausible to think along LaPlacean lines that the entire future of the universe was contained in its initial state.

I have a strong inclination to go with the scientists. Arguing the positions helps me understand them, but I’m unlikely to be convinced when it seems most physicists lacked any reluctance to adopt a probabilistic (that is, non-Bohmian) paradigm. Cosmologists generally assume that there’s no underlying determinisism. They’re in general in a better position to weigh the evidence against preconception than I, since they understand the evidence.

Unless, that is, I find a really strong philosophical argument, such as that objective (ontological) probabilities are incoherent.
#135 Stephen R. Diamond says:
22 Jul 2012, 5:51 pm
Joseph,

What do you think about actual infinities?
#136 joseph says:
22 Jul 2012, 11:21 pm
1. I might be wrong yes, this is a confusing matter, but as far as I can understand you can express a macroscopic object (a dog, as cats are over used) as a wave and work out the slit separation and width to get a diffraction pattern, just the sizes involved would be too small for a dog to pass through. There is no implicit size limit to quantum effects. Every book I’ve read on quantum uncertainty expresses it in terms of a measurement being taken using a photon, I imagine it’s possible I’ve got caught it overthinking the example. I think the analogy of taking photos of the car, shows how we could (epistemologically) be in a similar situation for macroscopic objects.

On 2., yes that’s why I’m not Bohmian (or a Bohrista, or an Everretian), but the original question (way back) was “does QM tell us there are truly random events?”. I think the answer is no, it isn’t that clear, there are important interpretations that do though. I believe all QM really tells us is to “shut up and do the maths”, I think that a commitment to any interpretation is merely a preference, every interpretation presents us with certain ideas which seem illogical, sadly, and currently we cannot distinguish interpretations experimentally. Why then to I devote so much time to Bohm-de Broglie? Intrigue. It’s a totally different account to the vaguely Copenhagen Interpretation I was taught, and it provides a counter point.

3. Yes, that’s another point I’ve been thinking about, we accept heliocentrism because it’s a simpler model than geocentrism, I’ve been trying to see if any interpretation can lay claim to being more simple. The answer I have found frustrates me. It is that some are easier for some results, others for others.
#137 joseph says:
23 Jul 2012, 12:37 am
For example the results of this experiment are very easy (relatively) to calculate using bohmian or time symmetric mechanics:

http://scienceblogs.com/principles/2011/06/03/watching-photons-interfere-obs/
#138 joseph says:
23 Jul 2012, 1:54 am
As for epistemic barriers being antithetical to science, I think the bohmian camp would sacrifice that for realism, as they’d regard non-realism as antithetical to science.

As for going with the scientists I think that leaves you with me, accepting that “shut up and do the maths” is all the physics tells us.

If you pushed further for the most popular interpretations among scientists your left with the C.I., or the M.W.I. , I can’t find a survey I’d consider reliable enough to post.
#139 joseph says:
23 Jul 2012, 2:24 am
Here is an interesting discussion on the “size limits” of quantum theory:

http://www.physicsforums.com/showthread.php?t=612717

Another quick note, I definitely don’t feel entitled to believe “Bohmian Mechanics”, or any other interpretation.
#140 Stephen R. Diamond says:
23 Jul 2012, 8:05 pm
On 2., yes that’s why I’m not Bohmian (or a Bohrista, or an Everretian), but the original question (way back) was “does QM tell us there are truly random events?”. I think the answer is no, it isn’t that clear, there are important interpretations that do though. I believe all QM really tells us is to “shut up and do the maths”, I think that a commitment to any interpretation is merely a preference, every interpretation presents us with certain ideas which seem illogical, sadly, and currently we cannot distinguish interpretations experimentally.

As for going with the scientists I think that leaves you with me, accepting that “shut up and do the maths” is all the physics tells us.

I wouldn’t individuate basic positions by their belonging to this or that interpretation. I’m uninterested in most of the details–are waves real, for example, really doesn’t much interest me. The two questions quantum mechanics addresses, for those looking for conclusions about the real world, are Bell’s issues: nonlocality and objective probability. [I mean, I think morality is fictitious; I've got to think something is real :)]

I’m not intrinsically concerned about locality, either; spooky action at a distance seems a concern of an earlier version of naturalism. I am concerned particularly about probability, as there’s some question–even in my mind–about whether objective probabilities are consistent with materialism.

But my point about scientific consensus is that physicists have overwhelmingly opted to accept objective probabilities (and also to infer absolute ontological barriers from absolute epistemological barriers). I’m much more comfortable with inferring ontology from epistemology than with objective probabilities, based on the history of science and on the implausibility that nature would conspire to totally close off our access to something real.

Acceptance of objective probabilities, pace Bohm, seems to have been thoroughly absorbed by science. I have never seen a cosmological model based on a determinist ontology! So it seems to me that, as scientists view qm, the evidence weighs heavily in favor of there really being objective probabilities.

Do Bohmians put realism ahead of the absence of epistemological gaps? My guess is that they don’t prioritize here: both are absolutely essential for science. This would come from basic materialist philosophy, to which Bohm himself adhered: reality is material AND it is knowable. I still haven’t confirmed or disconfirmed my forecast of Bohmian opinion. In other words: I’m willing to bet some small amount of Chinese currency that Bohmians reject the view that the epistemological or ontological limits accepted by (all) other interpretations of qm aren’t absolute; scientific knowledge of the hidden variables should eventually allow precise measurement in principle.
#141 Stephen R. Diamond says:
23 Jul 2012, 8:19 pm
1. I might be wrong yes, this is a confusing matter, but as far as I can understand you can express a macroscopic object (a dog, as cats are over used) as a wave and work out the slit separation and width to get a diffraction pattern, just the sizes involved would be too small for a dog to pass through. There is no implicit size limit to quantum effects. Every book I’ve read on quantum uncertainty expresses it in terms of a measurement being taken using a photon, I imagine it’s possible I’ve got caught it overthinking the example. I think the analogy of taking photos of the car, shows how we could (epistemologically) be in a similar situation for macroscopic objects.

But the object being measured must be small enough to be interfered with by a mere photon. How much uncertainty does measurement by a photon introduce into the car? Unmeasurably small. In principle, there’s some interference; there’s no absolute size limit. But in practice the inference caused by measurement is much, much, smaller than the uncertainty you’re talking about for measuring the car’s paramaters. That’s my understanding, anyway.
#142 joseph says:
23 Jul 2012, 9:04 pm
Stephen,
Would you allow averaged measurements from an interferometer as a violation of hidden variables? I think it’s unfair for me to argue that….but there is an argument for it.

As for macroscopic examples of a superposition there are SQUIDs (10^14 electrons) and quantum machines. I thought someone would raise them as an objection to bohmian mechanics. I think they show that there is no easy cut off between macro- and quantum…
#143 joseph says:
23 Jul 2012, 9:43 pm
Here is an example of the wavelength of a man, and the uncertainty of a mosquito:
http://answers.yahoo.com/question/index?qid=20091116171435AA9NEf6
#144 joseph says:
23 Jul 2012, 10:50 pm
I am on a brief holiday, so i won’t be able to converse so easily!

I’ll arrange a private wager with you if you like! But I need to know your opinion on the inferometer first.

I can pinpoint on key difference between us, I am extremely confident most bohmians reject the C.I. over realism.
#145 Stephen R. Diamond says:
24 Jul 2012, 2:07 am
Would you allow averaged measurements from an interferometer as a violation of hidden variables? I think it’s unfair for me to argue that….but there is an argument for it.

As for macroscopic examples of a superposition there are SQUIDs (10^14 electrons) and quantum machines. I thought someone would raise them as an objection to bohmian mechanics. I think they show that there is no easy cut off between macro- and quantum…

No idea what an interferometer is. Why does Bohm need a cut off?

I’ll arrange a private wager with you if you like! But I need to know your opinion on the inferometer first.

Just kidding about the wager. I just found the idea of doing it in Chinese currency humorous; I assume the exchange rate is pretty one-sided.

I can pinpoint on key difference between us, I am extremely confident most bohmians reject the C.I. over realism.

For sure. But that’s consistent with their rejecting realist approaches that propose that some things exist but are unknowable–most obviously, MWI.
#146 Stephen R. Diamond says:
27 Jul 2012, 12:28 am
Joseph,

Do Bohmians derive the expected probabilities? Or do they just accept the Born probabilities? If you know–
#147 joseph says:
27 Jul 2012, 2:44 am
An inferometer is, as I understand it, a bit of equipment that lets you take weak measurements. You can then analyse the weak measurements to produce the trajectories of individual photons:

http://scienceblogs.com/principles/2011/06/03/watching-photons-interfere-obs/

In this way you could argue hidden variables can be seen.

But I think it’s a swizz, in the sense that a Bohrista could fairly say, “Arr my boy, you are measuring, even if they are weak measurements, so of course you see photons as particles, not in there superposition state”.

I know you don’t want to argue particulars, but it does effect our logic. If the photon is a wave then a single photon can logically pass through two slits (which the Bohristas think it does, provided we don’t measure the photon before it passes through the slits). If we think of our photons as particles it is illogical to say a single particle passes through both slits, each photon passes through a single slit (whether it is measured or not, which is what the Bohmers think).

Weirdly in the Copenhagen Interpretation a photon is a wave if unmeasured (before passing through the slit), and a particle if measured (before passing through the slit).

I admit I am attacking the problem from multiple angles.

On the wager, I’m used to hearing that the Chinese are manipulating currency unfairly and numerous economies here peg their currency against the dollar. Damn shame, the opportunity to recieve money from a lawyer seldom presents itself ;-)

When you say:

that’s consistent with their rejecting realist approaches

Is “their” referring to Bohmians? If so why do you say they reject realist approaches? As in all I’ve read about this Pilot Wave Theory/ de Broglie Bohm interpretation / Bohmian mechanics are all labelled “realist”. I’ve missed a key point, I can see the edges of it.

Oh, before I forget, yes actual infinities, the only arguments I’ve heard against them are, a la William Lane Craig and Hilbert, the mathematics involved leads to paradoxical results. Other mathematicians seem to say this is false. I am of the impression they are possible. I’d be interested to know your opinion.

Again, due to my mathematical short comings I’m unsure how to answer your question as to how Bohmers derive probabilities. I’ll parrot a little from the wiki article and see if that is going in the right direction.

The general idea was that the Born Rule, with certain qualifications, is a theorem in relation to Bohmian Mechanics, there seems to be an analogy with entropy and the second law of thermodynamics in classical physics.
#148 joseph says:
27 Jul 2012, 4:51 am
I always manage to forget something:

Why does Bohm need a cut off?

No, not that I can see. The C.I. doesn’t really either, just (and I promise on all I hold holy [tea and Queen Elizabeth II], that I am not being sarcastic in my next 2 sentences) that most people aren’t comfortable with, a single photon travelling through two slits, a single electron travelling both clockwise and anti-clockwise around a superconducting ring, or our favourite cat being dead and alive. All of which are logically defensible…
#149 Stephen R. Diamond says:
27 Jul 2012, 1:30 pm
When you say:

that’s consistent with their rejecting realist approaches

Is “their” referring to Bohmians? If so why do you say they reject realist approaches? As in all I’ve read about this Pilot Wave Theory/ de Broglie Bohm interpretation / Bohmian mechanics are all labelled “realist”. I’ve missed a key point, I can see the edges of it.

You quoted me “out of context” by cutting off the restrictive clause (http://tinyurl.com/ydkgbul): “But that’s consistent with their rejecting realist approaches that propose that some things exist but are unknowable–most obviously, MWI.” I’m certainly not questioning that Bohmians are realists; just that their commitmens are more than merely realist (like MWI purports to be) but fully materialist, a stronger position that excludes unknowable realities like hidden variables unmeasurable in principle.

Oh, before I forget, yes actual infinities, the only arguments I’ve heard against them are, a la William Lane Craig and Hilbert, the mathematics involved leads to paradoxical results. Other mathematicians seem to say this is false. I am of the impression they are possible. I’d be interested to know your opinion.

The only mathematical question is whether they’re coherent. When Hilbert said they didn’t exist in nature, he was pronouncing on philosophy. The consensus among mathematicians (although there are exceptions) is that actual infinities are coherent, but the question is whether they are “metaphysically possible,” including whether there even is such a thing as “metaphysical possibility,” distinguished from physical possibility.

I raise the question because actual I “feel” the same way about actual infinities as I do about objective probabilities: I find it hard to understand how they could be possible. But I think that probably represents a limitation on intuition rather than reality. Probably the best expression of the intuition against ultimate probabilities is the principle of sufficient reason: if objective probabilities exist, they leave the specific outcomes without a “reason” in that the same objective circumstance result in different outcomes. (I recall arguing this point to my 12th grade physics teacher, who was obviously unimpressed.) The way I’d formulate the intuition that actual infinity seems to violate is “Everything that exists exists in some definite quantity.”
#150 Stephen R. Diamond says:
27 Jul 2012, 1:34 pm
“fully materialist, a stronger position that excludes unknowable realities like hidden variables unmeasurable in principle.”

To be clearer, I’m reaffirming my expectation that Bohmians believe hidden variables are measurable in principle, even if they don’t know how to measure them.

Do Bohmians hold that interferometers are a way forward toward measuring hidden variables?
#151 joseph says:
28 Jul 2012, 6:01 am
Apologies for quoting you out of context, some of the problem is my new “upgraded” operating system won’t allow me to copy from the comments section.

The way I am thinking is all interpretations have something that is unknowable:

Copenhagen; very obviously has it’s superposition states which magically collapse when entering a relationship with a macroscopic system of undefined size. (I’d say the particle is always in a relationship with the biggest macroscopic system out there, i.e. the universe…but I digress).

Many World; yep…the other worlds.

de Broglie-Bohm; hidden variables.

I would also note that in defending (which I think is fair, and you do it well) the Copenhagen interpretation, you are defending objective, ontological probability.

Interferometers – “Yes, sort of” is the answer to your question. A Bohmian interpretation of the results of the experiment would be that these results represent the flight paths of individual photons, which is what happens even if nothing is measured.

A Copenhagenist would say no.

By analogy (one I’ve stolen from H.Nikolic) say you wanted to find the weight of a sheet of paper, but your scales are only accurate to +/- 10 grams.

A Bohmist would weight a thousand sheets of paper, and lets say the result was 1kg, and say each sheet weighed 1g.

A Copenhagenist would say well the paper is not by any means uniform, so each sheet of paper weighs a minimum of -9g and a maximum of 11g, as the averaging trick only works if you assume uniformity.

Also I’ve held this back, as a thought.
If you had a photon of infinitely small wavelength, you could, in principle know the exact position of a quantum object (of course you’d know nothing of it’s momentum), the position would not be hidden. Does this count as the variable not being hidden “in principle”, or have I over-reached?
#152 joseph says:
28 Jul 2012, 7:06 am
An interesting argument against even classical causality:

http://quod.lib.umich.edu/p/phimp/3521354.0003.004/9?page=root;rgn=main;size=200;view=image
#153 Stephen R. Diamond says:
28 Jul 2012, 5:18 pm
Also I’ve held this back, as a thought.
If you had a photon of infinitely small wavelength, you could, in principle know the exact position of a quantum object (of course you’d know nothing of it’s momentum), the position would not be hidden. Does this count as the variable not being hidden “in principle”, or have I over-reached?

Can a photon have an infinitesimal wave length?
#154 Stephen R. Diamond says:
28 Jul 2012, 5:36 pm
An interesting argument against even classical causality:

The argument is that if you put a point mass at the apex of a symmetrical incline, there are solutions to Newton’s equations such that it can start moving at any arbitrary time. I don’t really see how that’s necessarily an argument. It seems to involve a fetishization of physics equations (which MWI advocates also seem to engage in). How one uses the equation, it seems to me, should be subordinated to one’s qualitative understanding. Many times quadratic equations, for example, have negative values as solutions when negative numbers have no meaning in the context; then you ignore the negative solutions. (Recall high-school algebra problems.) Similarly, I don’t see why the solutions to Newton’s equations which make no causal sense need be entertained.
#155 Stephen R. Diamond says:
28 Jul 2012, 6:04 pm
By analogy (one I’ve stolen from H.Nikolic) say you wanted to find the weight of a sheet of paper, but your scales are only accurate to +/- 10 grams.

A Bohmist would weight a thousand sheets of paper, and lets say the result was 1kg, and say each sheet weighed 1g.

A Copenhagenist would say well the paper is not by any means uniform, so each sheet of paper weighs a minimum of -9g and a maximum of 11g, as the averaging trick only works if you assume uniformity.

Isn’t the Copenhagenist clearly correct here? But the practical question is, when should you assume uniformity. The interferometer experimenter seems to have stronger reasons to assume uniformity than someone weighing 1,000 sheets of paper with a completely unknown weight distribution.

The problem I think I see with the interferometer approach isn’t its precision so much as its exclusion (of momentum). It doesn’t show that photons have classical physical properties if only one can be measured at a time.

Copenhagen; very obviously has it’s superposition states which magically collapse when entering a relationship with a macroscopic system of undefined size.

I’m not sure about the extent to which this view coincides with Copengahen, but if you view the “superposition” as a bundle of propensities, “collapse” is a mere metaphor for realizing a propensity. The realization of the propensity doesn’t abolish the “superposition.” The wave function rolls on its merry way despite having had some of its propensities realized.

(I’d say the particle is always in a relationship with the biggest macroscopic system out there, i.e. the universe but I digress)

See above. This only matters, it seems to me, when you can take a “measurement” using the entire universe as measuring instrument, which I take it was true only at the big bang.
#156 Stephen R. Diamond says:
29 Jul 2012, 12:46 am
The general idea was that the Born Rule, with certain qualifications, is a theorem in relation to Bohmian Mechanics, there seems to be an analogy with entropy and the second law of thermodynamics in classical physics.

That’s what I had suspected. But then, the Born probabilities shouldn’t be precise, just as the rate at which the entropy of a particular system increases isn’t precise. The Born probabilities would be statistical laws. This would have empirical repercussions, although they might be very hard to detect.
#157 joseph says:
29 Jul 2012, 1:22 am
Is a photon with a infinitesimally small wavelength possible? In principle, yes, I think so….
#158 Peter Hurford (author) says:
29 Jul 2012, 1:39 am
Hey Stephen, for what it’s worth, congrats on this one being my 2000th comment.

Also, I enjoy this back-and-forth and look forward to getting back into it when I can make the time.
#159 joseph says:
29 Jul 2012, 8:21 am
the problem I think I see with the interferometer approach isn’t it’s precision, so much as it’s exclusion (of momentum). It doesn’t show photons have classical properties if only one can be measured at a time

Well, I don’t think the approach excludes momentum, quoting from the blog:

Photons that enter the calcite perpendicular to the surface pass straight through, and travel a distance equal to the thickness of the calcite. Photons that enter at a shallower angle follow a longer path through the calcite (think of it like cutting a loaf of French bread on the bias– the angle-cut pieces are longer than the thickness of the loaf), and thus experience a greater change in polarization. The polarization of an individual photon then depends on the angle it took through the calcite, which tells you the direction of its momentum. The magnitude of the momentum is determined by the wavelength, which is the same for all the photons, so this gives you the information you need for the trajectory

So momentum is not excluded, a “weak measurement” is taken and, if you like the momentum is reconstructed.

Heisenberg uncertainty does apply to classical objects too though, as I showed with the example of the Mosquito, so the lesson, I think is not photons are not classical because there is a relationship between the uncertainty of momentum and uncertainty of position, but that all objects have this characteristic.

Re the paper analogy I tried to leave it open as to who was right, to make the analogy fair. You’re right, which Interpretation is correct depends on whether the assumption of uniformity is correct, or not.

If collapse is metaphorical, I’m on board, because I prefer to think of superposition states as epistemological anyway.

As far as all quantum objects being not being in a relationship with the universe since the big bang well:

1/ they’d still be in a relationship with the bit of the universe in their light cone, which definitely counts as a macroscopic system.
2/ assuming determinism, the bits of the universe that the atom/photon/electron/ whatever was in a relationship with before space itself expanded faster than the speed of light (hyperinflation) still has an influence on the future of that object (the objects history).
#160 joseph says:
29 Jul 2012, 12:21 pm
http://arxiv.org/abs/0804.4656

This is supposed to be a prediction that is made by the fact that the Born Rule emerges as a theorem from deBB, rather than being a law as in CI.
#161 Stephen R. Diamond says:
29 Jul 2012, 3:13 pm
Heisenberg uncertainty does apply to classical objects too though, as I showed with the example of the Mosquito, so the lesson, I think is not photons are not classical because there is a relationship between the uncertainty of momentum and uncertainty of position, but that all objects have this characteristic.

By “classical object” I mean (I think conventionally means) an object with properites as classically conceived. So, using this terminology, under a propensity view there are no classical objects. But under a Bohm view (I think) all objects remain classical.

As far as all quantum objects being not being in a relationship with the universe since the big bang well:

I wasn’t saying they weren’t in a relationship. That’s not the “propensity” criterion. It’s just that there’s no point in taking the relationship as a “measurement” unless the objects in relationship straightforwardly express quantum facts.

This is supposed to be a prediction that is made by the fact that the Born Rule emerges as a theorem from deBB, rather than being a law as in CI.

I don’t understand it (nor do I have anything useful to say about infinitesimal wavelengths) but it “sounds” promising, in that it seems to me that cosmology should be a direct battleground for the interpretations.

Offhand, it seems to me that interferometry does provide a pretty good argument for Bohm. The demonstration would seem to me not that a photon exists without being measured. As you point out, a weak measurement is still a measurement. The point is rather that, pace CI, the photon has classical properties: it has velocity and momentum simultaneously. I don’t see at the moment how CI (or a “propensity” view) can rebut this.

On cosmology, have any Bohmians advanced general cosmological theories? They idea of the big bang as a chance event, which seems to reign in cosmology, is closed to a strict determinist. It seems to me a periodic universe should be appealing to a Bohmian, as I think there may be a way that such a view would avoid not only real chances but also actual infinities.
#162 Stephen R. Diamond says:
29 Jul 2012, 6:00 pm
SRD: “On cosmology, have any Bohmians advanced general cosmological theories?”

I notice that a leading Bohmist, Antony Valentini, was a student of Lee Smolin, a leading and dissident cosmologist. But Smolin doesn’t seem to be a Bohmist; his cosmology depends on real chances.

Unrelated, a very interesting historical note (from Wikipedia):

Later, in 1932, John von Neumann published a paper claiming to prove that all hidden variable theories were impossible.[11] (A result found to be flawed by Grete Hermann three years later, though this went unnoticed by the physics community for over fifty years). However, in 1952, David Bohm, dissatisfied with the prevailing orthodoxy, rediscovered de Broglie’s Pilot Wave theory. Bohm developed Pilot Wave Theory into what is now called the De Broglie-Bohm theory.[12]

Of all the interpretations I’ve seen of qm, btw, von Neumann’s is the only one I’ve thought can be dismissed out of hand.
#163 Stephen R. Diamond says:
29 Jul 2012, 6:58 pm
I’m going to be bold and reveal my cosmology. It’s a novel view, which in light of my not being competent in physics, makes it almost certainly wrong. But I’ve considered it for a long time, and it has the merit of being, I think, the view most consistent with a thoroughgoing materialism.

The universe expands to some limit, then contracts back to the big bang, “after” which it expands in exactly the same fashion. (Shades of Nietzsche’s [the only word I can't remember how to spell] eternal recurrence.) This part isn’t original–theories of a periodic universe have been around, although I’m not sure they’re committed to exact duplication.

My novel wrinkle is that I apply Leibnitz’s principle of the identity of indiscernibles to conclude that since there’s no way to distinguish one period from another–no different features, no common time frame in which to distinguish–there’s really only a single period. This avoids actual infinities, a good thing insofar as they’re metaphysically suspect and a crucial thing if they’re metaphysically impossible. It also may avoid problems concerning entropy and perpetual motion, at least at the verbal level: the periodic universe doesn’t truly repeat. There’s one cycle that’s eternal.

On actual infinities, here’s a puzzle that weighs more strongly in my thinking than Hilbert’s Hotel Paradox. Let’s say the universe has an infinite quantity of both matter and space–as far as I can tell, the two must go together. Then what is the average density of matter in the whole universe? It’s undefined. This means that I can take an arbitrarily large expanse of space and another contiguous arbitrarily large expanse of space, compute the density of the first but yet obtain no information about the density of matter in the second arbitrarily large expanse. An ad hoc proviso in maintaining that ordinary physical ratios simply don’t apply to the universe taken as a whole.
#164 Stephen R. Diamond says:
29 Jul 2012, 6:59 pm
Hey Stephen, for what it’s worth, congrats on this one being my 2000th comment.

Also, I enjoy this back-and-forth and look forward to getting back into it when I can make the time.

Glad to hear it. Believe it or not, I do worry about “over posting.”
#165 joseph says:
30 Jul 2012, 2:40 am
I think I agree with you that:

on a bohmian view all objects remain classical

Though I would rather word it:
“on a bohmian view there is no distinction between macroscopic and quantum objects”

I am confused by your objection to relationships. It seems you are saying a relationship wouldn’t (I’m trying to use your terminology, but am afraid I’m going to bollock it up because of both my lack on familiarity, and the difficulty in defining propensity) result in propensities being realised, and becoming quantum facts (?). Usually when we take a measurement, on a copenhagen-ish account, the thing being measured is said to enter a relationship with a macroscopic object, and the fact that the uncertainty of the macroscopic object is so miniscule collapses the superposition state (realises the propensity). My objection is thething being measured is in a relationship with a large macroscopic object already (all that in it’s light cone, at least), everything in it’s light cone has a low uncertainty, and so must be as “good” if not “better” at collapsing the superposition state (producing a quantum fact) as a puny measuring device in a lab.

I agree that a bohmian model would be exspected to lead to an eterna universe, many philosophical objections (and counters) are seen in WLC’s Kalam Argument.

Stephen, there is a word you cannot remember how to spell? My entire belief system just collapsed! ;)

Von Neumann seems to be an extremely clever man who over extended himself in this regard, but in doing so ensured that Bohm’s ideas couldn’t be seriously discussed for many years.

I will think on your infinite universe puzzler.
#166 Stephen R. Diamond says:
30 Jul 2012, 10:00 pm
Usually when we take a measurement, on a copenhagen-ish account, the thing being measured is said to enter a relationship with a macroscopic object, and the fact that the uncertainty of the macroscopic object is so miniscule collapses the superposition state (realises the propensity). My objection is thething being measured is in a relationship with a large macroscopic object already (all that in it’s light cone, at least), everything in it’s light cone has a low uncertainty, and so must be as “good” if not “better” at collapsing the superposition state (producing a quantum fact) as a puny measuring device in a lab.

The “collapse” is just a macroscopic take on quantum processes. It is quantum processes under a macroscopic description.

This point seems to relate to:

on a bohmian view all objects remain classical

Though I would rather word it:
“on a bohmian view there is no distinction between macroscopic and quantum objects”

On a propensity view, there is also no distinction between macroscopic and quantum objects. The difference is that on Bohmian view quantum objects are classical and on a propensity view classical objects are quantum.

I don’t think propensities are hard to understand (to the extent that potentially incoherent concepts can be “understood” even if incoherent). I think their problems (at the moment I think they’re fatal)–apart from the potential incoherence of objective probability–is that they incorporate the measuring process into the theory proper. If a “theory” makes direct reference to the measuring process, that seems like (perhaps) decisive evidence that it’s really a model and not a true theory. Ontologically, measurement is a function of matter and not the other way around. Put otherwise, it becomes a miracle why qm-arbitrary configurations (macroscopic objects) should fit so nicely into a theory framed at a totally different level of abstraction.
#167 Stephen R. Diamond says:
30 Jul 2012, 11:57 pm
I agree that a bohmian model would be exspected to lead to an eternal universe, many philosophical objections (and counters) are seen in WLC’s Kalam Argument.

The Kalam argument concerns actual infinities. If actual infinities are objectionable at all, they’re less objectionable something out of nothing, and I consider theism incoherent. But in my cosmology, for what it’s worth–and however small that is, it’s worth more than the silly Kalam argument for a deity–you have eternity without infinity. I think it’s the only way to get there.

There is another model that gives you a kind of eternity without infinity: Stephen Hawking’s model, which I think is what Peter calls finite eternalism–good name. The problem with it, seems to me, is that the temporal location of the origin, 14 billion or so years in our time frame, is unexplained, and it’s hard to see how it could be explained.

One thing I don’t like about actual infinities is that they’re just to easy to posit to derive what you want. Do you know: does MWI say the “many” worlds are infinite? How many are there, really?
#168 Stephen R. Diamond says:
31 Jul 2012, 2:06 pm
“One thing I don’t like about actual infinities is that they’re just to easy to posit to derive what you want.”

For example, by means of “anthropic” arguments.
#169 joseph says:
1 Aug 2012, 11:44 am
I am mulling things over, but I think the main trouble with the propensity view is any of the current interpretations could fairly be called a propensity view…
#170 Stephen R. Diamond says:
1 Aug 2012, 2:02 pm
What distinguishes what I call a propensity view (which I see essentially as CI with metaphors removed) is:

1. Objective (ontological) probabilities (pace MWI and Bohm):

2. No ontological collapse (Rules out straight CI)

3. All objects are inherently non-classical (Not Bohm)

4. Classical objects are nonetheless incorporated in the theory in the description of the measurement process.
#171 joseph says:
1 Aug 2012, 2:27 pm
As far as I can tell:

1. All the views have objective probabilities, CI would say they are ontological (the superposition state is real), Bohm would say epistemological (the superposition state relates to lack of knowledge), MWI would say….I guess something like all probabilities are realized, but one per world so in an individual world the superposition state is epistemological, but in all the worlds it is ontological.

2. No real collapse, also seems to rule out CI, but also seems to conflict with the previous statement,3 after all any measurement gives us one result, not a mixture of results. This can’t happen if there are ontological probabilities, if there are collapse must occur (otherwise a measurement would give us a mixed answer, which it never does, not even weak measurement).

3. All objects are non-classical (not bohm) – well remember Bohm also says classical objects follow the same laws as quantum objects, and the laws are not all classical (photons do not travel in straight lines), so you could equally say under Bohm, everything follows quantum laws. Also this contradicts CI and MWI (I’d hazard) both of which have a quantum-macroscopic cut off (for collapse and decoherence, respectively).

4. Classical objects are in the description of the measurement process – seemingly contradicts the earlier statement that there is no distinction. I know you talked of a mathematical limit with an early asymptote, my question then is how is the particle ever out of interaction with it’s immediate environment, which must surely exceed this early asymptote?
#172 joseph says:
1 Aug 2012, 4:22 pm
Just in case this is the point of confusion, and hopefully not to cause offence, the superposition state and the heisenberg uncertainty are different beasties.
#173 Stephen R. Diamond says:
1 Aug 2012, 4:47 pm
1. Bohm doesn’t have objective probabilities. Even the epistemological limits apply only as approximations under specific conditions. But even if you want to call these limits objective, the point is that propensity theory make them ontological. So, you can’t say every theory is a propensity theory. Epistemological probabilities aren’t propensities–as defined by Popper.

Perhaps a clearer term for “objective probabilities” is nonreducible probabilities. Bohm reduces probabilities to deterministic underpinnings. (I think MWI in these terms is nonreducible, in that it merely takes over the Born probabilities, without explaining them or even with much possibility for explanation.)

2. “all any measurement gives us one result, not a mixture of results. This can’t happen if there are ontological probabilities, if there are collapse must occur (otherwise a measurement would give us a mixed answer, which it never does, not even weak measurement).”

A measure doesn’t give a mixed answer because a measurement is a macroscopic take on quantum processes, and macroscopic objects have negligible uncertainty. You seem to resist idea because you keep coming back with this objection. You haven’t told me why you think it doesn’t make sense for the wave function to continue to operate when a “measurement” is taken, the measurement only expressing the propensities.

3. Good point that Bohm’s objects aren’t entirely classical, but the relevant issue is whether they’re classical with respect to having a velocity and momentum (and other such properties) simultaneously.

4. “how is the particle ever out of interaction with it’s immediate environment, which must surely exceed this early asymptote?”

It doesn’t need to be out of interaction with its environment. All of its interactions have a macroscopic and quantum description. Measurement is the process of finding the macroscopic description of a particular interaction.

As I said, the problem I see with this is that the effect of the measurement process (and of macro-interactions generally) stated in qm terms must be assumed to be consistent with the posited effect of interactions, without any proof that this must be so. CI makes measurement a miracle; propensity make the effects of measurements on subsequent measurements a miracle. (Actually, I think CI’s miracle is easier to accept than propensity theory’s.)
#174 Stephen R. Diamond says:
1 Aug 2012, 5:26 pm
” the superposition state and the heisenberg uncertainty are different beasties.”

In the propensity theory, the superposition is a bundle of propensities expressed in macroscopic terms. Heisenberg Uncertainty is a law constraining the expression any propensity (again expressed in macroscopic terms).
#175 joseph says:
1 Aug 2012, 5:29 pm
OK I’ll try to give an example, which might illustrate the difficulties I’m having with point 2.

Take a SQUID (which I mentioned previously).

The superposition state (which I assume we could call the quantum description) says the individual electron travels both clockwise and anti-clockwise around a superconducting ring.

It was equal propensities to travel clockwise and anti-clockwise.

Copenhagen answers this by saying, yes before the measurement it actually does both.
Bohm says no, an individual electron travels either clockwise or anticlockwise.

On my understanding of propensities, probabilities being objective, yes the single electron does indeed travel clockwise and anticlockwise.

On the next point, we take a measurement of a single electron, we always get the result of either clockwise or anticlockwise:

CI solves this by saying the superposition collapses.
Bohm says, sure that’s what the electron was doing.
Propensities seems to say, yes objective probabilities are true, so it was going clockwise and anticlockwise, no the superposition does not collapse, but somehow (this is where my understanding fails) the macroscopic description is one or the other.
#176 joseph says:
1 Aug 2012, 5:31 pm
But the superposition state and heisenberg uncertainty have entirely different constraints right?
#177 joseph says:
1 Aug 2012, 7:31 pm
So using my example, why don’t I think the wave function continues to operate after a measurement is taken?

This would mean that the single electron (in the SQUID set up) was (before measurement, or macroscopic description) is moving anticlockwise and clockwise (as the wave function describes).

Upon measurement (macroscopic description) the electron is then either moving clockwise or anticlockwise.

After measurement the single electron is then moving clockwise and anticlockwise again (as the wave function describes).

The thought occured that you might be saying that there is Quantum description and a Macroscopic description, my question would then be how can both be ontologically true, and yet give contradictory answers?
#178 Stephen R. Diamond says:
1 Aug 2012, 9:56 pm
After measurement the single electron is then moving clockwise and anticlockwise again (as the wave function describes).

This is where we differ in our understanding. The wave function doesn’t necessarily prescribe that the probability is .5. That probability is determined by the experimental setup. After the measurement is performed, the wave function is based on changed values. If we could compute whole complex of quantum interactions constituting the disturbance–that is the measurement–it would be found that they impart very close to 1 and 0 propensities to the electron’s spin.

That’s what you’d have to say, and I think (but I could be wrong) that it’s consistent (assuming the very idea of objective probability is consistent). The problem is there’s no explanation–apparently no possible explanation–for why the quantum interactions correspond closely to the macrointeractions. That is, no proof that the macrointeractions reduce to quantum interactions or even a good independent reason to think they do. But I’m not certain of this line of criticism.
#179 joseph says:
1 Aug 2012, 10:05 pm
Have to get back to you on this, as I am working nights and so must sleep, but a brief note…in the SQUID setup, as I understand it, the probability is 0.5, sorry if I seemed to be taking that for granted.
#180 Stephen R. Diamond says:
2 Aug 2012, 1:20 am
On actual infinities, here’s another argument I came up with. (I’m sure it’s not novel.) It seems to express the anti-infinite intuition clearly.

Let’s say the universe consists of atoms, and they are infinite. Now, define a set such that every atom is a member: the set of all atoms. Are there any atoms that aren’t in the set?

If there are, then the set didn’t include all the atoms, per hypothesis. If there are none, the atoms aren’t infinite: you can add an element to an infinite set and still have infinity.

I think the infinitist would answer that set theory doesn’t allow defining a master universal set, and in effect, that’s what’s being done. But it seems to be part of the concept of physical objects that they can be aggregated into sets conceptually. We can define a set of all the atoms in the solar system; why not all the atoms in the universe?
#181 joseph says:
2 Aug 2012, 12:51 pm
Ok, so just a recap, here’s a quick description of a SQUID, which are candidates for producing QBITs (for Quantum Computing, which will solve all our problems and possibly kill everyone, if the singularity institute are correct):

http://en.m.wikipedia.org/wiki/SQUID

So, sorry not to have been more clear, but here we are not discussing electron spin, but the movement of electrons around a macroscopic ring. Large numbers of electrons.

So in complete subjection to Heisenberg’s Uncertainty, we could theoretically, accurately measure the momentum (thus direction of movement) of an electron without disturbing the momentum, we’d have to sacrifice certainty on the position, the position would be uncertain. We could do this with a low frequency photon.

On your line of criticism, I have, and on a gut level, cannot see a reason to seperate the macroscopic and the quantum. I think either superposition states are a reality for both or neither. You’ve talked of a limit with an early asymptote, set by experimental evidence, but at the end of the day it seems a subjective opinion (as to what exactly counts as significant quantum effects) is the best that could be attained.
#182 joseph says:
2 Aug 2012, 12:55 pm
I regret my understanding of the infinite in mathematics is so low that I feel any attempt to answer on my part would seem disrespectful to mathematicians.

The kalam argument as I understand conflates relational infinite time with eternity, and I think I understand relativity to mean we are left with relational infinite time?
#183 joseph says:
2 Aug 2012, 1:02 pm
Damn, sorry QUBITs, not QBITs.
#184 joseph says:
2 Aug 2012, 7:08 pm
Out of curiousity has anybody any opinions on Objective Collapse Interpretations?
#185 Stephen R. Diamond says:
2 Aug 2012, 9:37 pm
“The kalam argument as I understand conflates relational infinite time with eternity, and I think I understand relativity to mean we are left with relational infinite time?”

I’ve never heard that response, and I don’t understand it. The basic question it raises is whether you can have a universe infinitely old (by an measure). Here’s how I’d put the basic idea. If the present universe was preceded by an infinite series of causes, then it has in effect counted up to infinity by the present time. But that’s impossible, by definition.
#186 Peter Hurford (author) says:
2 Aug 2012, 11:21 pm
Weighing in on Kalam and actual infinities, you guys would probably be interested in Wes Morriston’s “A Critical Examination of the Kalam Cosmological Argument (PDF)”.

Though I’d personally suggest actually infinite time isn’t an issue because time doesn’t flow in the standard way; also see here, here, and here (PDF).

…Weighing on QM again will take some time.
#187 joseph says:
3 Aug 2012, 10:40 am
My rough understanding of relativity is that time slows (dilates) at regions of high curvature of space, as the singularity at the start of the big bang represents the ultimate curvature I’d imagine (according to relativity) time would slow to a rate of zero (which gives us a whole bunch of other questions, like is time quantized, how does anything start if no time is passing).

Here is where I came across the idea:

http://www.infidels.org/library/modern/james_still/kalam.html
#188 Peter Hurford (author) says:
3 Aug 2012, 11:51 am
Here is where I came across the idea:

http://www.infidels.org/library/modern/james_still/kalam.html

Right. Even if the universe has a finite age, it’s still true that the universe has always existed, there was nothing before the universe, and there was not a point in time where the universe didn’t exist.
#189 Stephen R. Diamond says:
3 Aug 2012, 1:36 pm
Yes, that’s what I referred to as Hawking’s Model (or Peter’s excellent phrase, finite eternalism). It avoids actual infinities. From the outside, it looks to me like the best model around, but it isn’t completely satisfying, which is why cosmologists play with multi-universe theories which do appear to require actual infinities. But they’re ruled out if actual infinities can’t exist physically. Yet, the purveyors seem unconcerned with the possibility. So, the issue seems relevant to cosmology, although a finite model avoids it. (Apologies for not recognizing it when you first mentioned it, Joseph. I think of it under other rubrics.)

But even those who embrace the Hawking model consider it an open question whether the universe has an overall curvature, making it finite in space-time or is flat, making it infinite. Ff there are no actual infinities, it’s a settled question: the universe must be curved and finite, despite being eternal.

Also “many worlds” interpretations posit (as far as I can tell) an actual infinity of “parallel” universes. So, MWI must be false if there can be no actual infinities. This argument, again as far as I can tell, seems to have been ignored by critics of MWI. Metaphysically, it’s very important, in that the multiple universes correspond to probabilities. But alternatives of finite size comprising an infinite set each take up only an infinitesimal part of that set, no matter how finitely large each alternative is. So MWI seems to falter by introducing actual infinities (if they’re metaphysically unacceptable), and they also falter (of this I’m less sure) by conceiving of finite probabilities as finite portions of an infinite space. (In general, MWI is mum on how it actually gets the probabilities; it just carries over the Born probabilities without any underpinning.)
#190 joseph says:
3 Aug 2012, 1:57 pm
I was guessing it was a problem with the name, doesn’t it (if time is not quantised – big if) provide for an infinite number of causes? I.e. relative to our current universe in quite flat space, there is an infinity of time at the start of the big bang? I’m on thin ice here, so if I’ve gone wrong just tell me.
#191 joseph says:
3 Aug 2012, 2:07 pm
Yes the number of worlds gives me some pause, even though it relies on a single principle. Now the moment of “decoherence” gives me the same problems as “wave form collapse”. Yes, as I understand it the MWI has a funny relationship with Born.

I think, but I’m having some problems confirming this, that in it’s original formulation the CI has some problems with relativity (hence Quantum Field Theories), and even in those forms there are difficulties. So a lot has been said about the problems of de Broglie-Bohm and relativity, I’d like to point out, it’s not alone.

Also to Peter Hurford directly, what does your view of time have to say about retrocausality? I’ve read part of the first link so far…
#192 Stephen R. Diamond says:
3 Aug 2012, 5:22 pm
Doesn’t it (if time is not quantised – big if) provide for an infinite number of causes? I.e. relative to our current universe in quite flat space, there is an infinity of time at the start of the big bang? I’m on thin ice here, so if I’ve gone wrong just tell me.

I think it’s a potential infinity rather than an actual infinity. With the Hawking view, the big bang doesn’t count as an actual event. If your ever reached it, you’d get an actual infinity of time. But you can’t. Nor can you start time at the big bang point, only as close as you want to the point. That produces only finite time and finite causes.

[An unrelated example of a potential infinity--just so you get the concept--is involved in Zeno's paradox. You make an infinite number of trips, when you keep dividing the interval in half, but this is an infinity that can be completed. (I don't think the actual-potential distinction quite nails it, but there does seem a metaphysical difference between structured and unstructured infinities.]
#193 Stephen R. Diamond says:
3 Aug 2012, 5:27 pm
Now the moment of “decoherence” gives me the same problems as “wave form collapse”.

The “propensity” view I had constructed eclectically and tried to defend takes the same approach to measurement–I think but am not sure–as the views called decoherentist or at least some of them. My tentative conclusion, to repeat it, is that it just transfers the problem from measurement to repeated measurement. Decoherence, for the benefit of other readers, is associated with MWI but not restricted to that view.
#194 Stephen R. Diamond says:
3 Aug 2012, 5:52 pm
So a lot has been said about the problems of de Broglie-Bohm and relativity, I’d like to point out, it’s not alone.

QM itself, as you point out, is incompatible with general relativity. One big difference is that qm implicitly assumes absolute space and time. Bohm just seems to make the difference explicit by introducing an ether. Since I think Leibnitz showed and time were relative long ago, I don’t like it. But perhaps it’s really no worse in that respect, if the only difference is in the degree of explicitness.
#195 joseph says:
3 Aug 2012, 6:32 pm
But I can point to versions of de Broglie-Bohm that do not take place in absolute space and time, doesn’t that effect your appraisal?

I lack the skill to say if they are any better than relativistic formulations of the C.I.

I see what you mean as being a potential infinity, in that you could, (a theory of time) count back to it and never reach it, the thing that makes me rub my temples is according to the theory it stilk “actually” happened…meaning…my brain shrugs.
#196 joseph says:
3 Aug 2012, 6:38 pm
Here you go Chief:

http://www.springerlink.com/content/y23q534285n7170l/
#197 Stephen R. Diamond says:
3 Aug 2012, 8:50 pm
you could, (a theory of time) count back to it and never reach it, the thing that makes me rub my temples is according to the theory it still “actually” happened
meaning
my brain shrugs.

There no mathematical inconsistency in denying it actually happens, but is there a metaphysical defect? Is there something, in other words, that makes it inconceivable rather than somehow unsatisfying? Or if it’s unsatisfying, can we articulate the defect that makes it unsatisfying? But particularly the first, inconceivable?

The logical possibilities I see are: 1) there was a first cause (implying agnosticism is unavoidable); 2) the so-called origin of the universe “occurs” at a horizon (Hawking); 3) there were an actual infinity of causes (the classical materialist picture)–but perhaps truly inconceivable; 4) the universe is periodic and determined–so that one period logically becomes an eternity.

I think materialists developed a liking for infinite universes because that was the only materialist picture until curved space-time. I’m not sure that any philosopher could or did anticipate that development in mathematics and its application to physics. So, we can make do with a finite world (and avoid Kant’s antimonies), but infinity has its allures apparently, and you have proposals for every manner of applying infinity. Many worlds, parallel universes, tegmark universes, and David Lewis’s realist theory of possibilia.
#198 Stephen R. Diamond says:
3 Aug 2012, 10:49 pm
Joseph, On quantized time: Am I correct in thinking that for Bohm quantization is purely epistemic; that the Bohm view, speaking ontologically, substitutes continuous variables for quantized variables. For some reason, I’ve assumed this, but I don’t recall why.
#199 joseph says:
3 Aug 2012, 10:55 pm
I admit I’m not sure, not yes, it does seem that would be in line with Bohmian thought in general. More generally as well, I’ve seen planck time represented as an epistemic limit, though I have wondered if this is because planck mass is embarrassingly high.
#200 joseph says:
3 Aug 2012, 11:22 pm
Given I often think of planck time as ontological; that points to an embarrassing incoherence in my thinking.
#201 joseph says:
4 Aug 2012, 10:06 am
A nice link that didn’t give me a headache:

http://www.phys.unsw.edu.au/einsteinlight/jw/module6_Planck.htm
#202 Peter Hurford (author) says:
4 Aug 2012, 2:21 pm
Stephen: Also “many worlds” interpretations posit (as far as I can tell) an actual infinity of “parallel” universes. So, MWI must be false if there can be no actual infinities.

My understanding was that there aren’t an infinite amount of universes, but rather an extraordinarily large finite amount of universes that continues to increase.

~

Joseph: what does your view of time have to say about retrocausality?

I think it’s plausible. I don’t have the relevant background, but I’m sympathetic to the Feynman-Stueckelberg Interpretation of antimatter as normal matter traveling backward through time. Such retrocausality also is the basis of Richard Carrier’s interpretation of quantum mechanics.
#203 joseph says:
4 Aug 2012, 5:07 pm
Hmmm….his theory is also Lorentz Invariant.
#204 Stephen R. Diamond says:
4 Aug 2012, 7:39 pm
My understanding was that there aren’t an infinite amount of universes, but rather an extraordinarily large finite amount of universes that continues to increase.

OK, you’re probably correct. Do you know what determines how many worlds arise from each split?

From what I gather, Carrier’s theory isn’t ready for serious physical consideration, in that Carrier himself doesn’t claim it actually works mathematically. Last I checked, he asked whether any physicist might assess it, but I don’t think he’s had any serious takers. I don’t know I’d put a very high prior on someone who doesn’t know how to check whether the theory works actually got it to work.

What makes me skeptical is just how hugely successful it is, in that he has, if I’m not mistaken, a nonlocal, determinist theory.
#205 Stephen R. Diamond says:
4 Aug 2012, 7:41 pm
I meant to say a local determinist theory.
#206 joseph says:
4 Aug 2012, 8:22 pm
Thought I’d share this:

http://www.conservapedia.com/Quantum_mechanics

Overall it’s not a bad article…but there is a part where the C.I.
is said to imply the existence of souls.
#207 Stephen R. Diamond says:
5 Aug 2012, 1:48 pm
Sometimes the topic arises of finding a good theist blog. Here’s one that arguably the best that I never see mentioned on pop-atheist and pop-theist blogrolls: Alexander Pruss’s Blog

Today, he has a brief post on the metaphysical point that contains this discussion of randomness: the principle of sufficient reason. (Alexander Pruss’s Blog: God and the Principle of Sufficient Reason – (http://tinyurl.com/8fmtra2)
#208 Stephen R. Diamond says:
5 Aug 2012, 11:24 pm
I think it was in this thread that Joseph and I discussed solipsism, and I must repudiate my argument. I tried to argue that solipsism was testable. I did this by invoking a Bayesian framework and making a seemingly plausible assumption that I probably wasn’t entitled to–inasmuch as the coherence of the distinction hadn’t been established.

What I would now say is that solipsism is incoherent. Essentially, what you mean by saying you know you exist and nothing else is that you have a direct awareness of your own consciousness. But we can refer to contents of our own consciousness only by using concepts tacitly based on the external world, meaning we can’t in principle have knowledge using concepts that don’t assume the world. And anyway, these contents conscious contents don’t exist. This is the topic of my blog posting on qualia – http://tinyurl.com/c3zq8ht

Joseph also gave me the idea of using dogs when he mentioned a friend who said he wouldn’t treat a pet because the pet lacked a soul. “Soul,” I think, actually serves theists as an explanation of qualitative consciousness, why they deny to animals. I think “common sense” gives dogs qualitative consciousness, but metaphysical reasoning denies it to all species.
#209 joseph says:
6 Aug 2012, 1:51 am
I wondered if that was anything to do with me! I decided it was more likely because we had been discussing slaughter. I must mention the person who refused his/her dog medical care on the basis of it “lacking a soul” was no friend of mine.

Interesting argument on solipsism, I’ll think about it when I wake up.
#210 Stephen R. Diamond says:
1 Sep 2012, 7:08 pm
My understanding was that there aren’t an infinite amount of universes, but rather an extraordinarily large finite amount of universes [according to MWI) that continues to increase.

It seems there’s not only any infinite number of universes according to MWI but a nondenumerable infinity of universes. (That is, analogous to the set of real numbers rather than the set of integers.) From http://physics.stackexchange.com/questions/32501/many-worlds-how-often-is-the-split-how-many-are-the-universes-and-how-do-you

You imply that there is a spectrum (a countable infinity) of “possible universes”. But is it actually a continuum (an uncountable infinity) of “possible universes”? Can the delta-function have non-zero values at locations everywhere between 0 and +/-1? Or maybe a better example (since I don’t understand the delta-function), in the double-slit experiment, can’t a particular photon hit the detector plane at any point on the plane? (<- thus uncountable infinite possible universes) – John Berryman Jul 21 at 13:04

@John Berryman The word 'spectrum' does not imply a countable infinity. It is a continuum representing an uncountably infinite number of universes in the example I gave. You can think of a delta function like a very narrow spike. The schrodinger equation time-evolves a narrow spike into a wider and wider gaussian shape. In the example, in order to keep things simple, I approximated this as {-1,0,1) (a very rough approximation, but serves to illustrate the point). – user1247 Jul 21 at 19:05

But I wouldn’t mind a more authoritative source.
#211 Stephen R. Diamond says:
2 Jan 2013, 2:26 pm
But what do we do when we can’t apply any of the four views? Search for more data. We’re going to need more information from physics before we can determine how the universe came to be, or whether it is located within some larger multiverse structure, and whether this multiverse structure is infinitely old or not, etc.

I’m really far from certain about whether infinite sets can actually exist, but I find it odd that philosophers have had so little to say about the matter in recent decades. The consensus seems to be, as you say, that it’s a question of data. I have a somewhat different opinion, in that while it would be most wise to foreclose science by philosophical reasoning, philosophy still has some bearing on the question.

In just-posted “Can infinite quantities exist?” ( http://tinyurl.com/aqcy99w ) I provide two original (and I think novel) conceptual arguments against actually realized infinite sets. Very skeletal (1,000 words.) Also includes philosophical speculation about the cosmological implications: the arguments recommend the Gold model of the universe that Einstein once favored.
#212 joseph says:
3 Jan 2013, 2:34 am
Hi Stephen,
I’ll give it a read, the most I’ve read about infinities has been W.L.Craig’s Kalam Argument, or G.Oppy’s criticisms of the afore mentioned. Perhaps strangely W.L.Craig seems to support the de Broglie-Bohm interpretation as he likes to believe, paraphrasing, that nothing lacks a cause (apart from his God), and yet denies actual infinities. Not that I want a theistic argument, just that it seems contrary to how our discussion has developed here.
#213 srdiamond says:
8 Jan 2013, 12:10 am
Hi Joseph,

I’m far from being (or wanting to be) an expert on Craig, but my take on this seemingly anomalous position (hidden variables typically being construed as materialist–I implicitly adopt it in my argument against actual infinite sets) is that it’s due to Craig’s being caught between the implications of q.m. and classic arguments. Historically, both actual infinities and determinism were embraced by materialists because it was impossible to see how a finite universe could be possible before mathematicians developed the geometries of curved space. (And it required Einstein to see, even afterwards, how they could be physically realized.) If the universe were finite in time, it would need a creator or acausality; if the universe were finite in space, it would need boundaries (the heaven above).

But I don’t think that’s the smartest move today for a theist. If I were a theist apologist, I would argue that q.m. shows that the laws of nature dictate only probabilities, meaning that some nonmaterial “cause” must select the individual occurrences and see that they average out correctly. Not that I think by any means its a strong argument, but given the modern picture of the world, it’s sure better than kalam.
#214 srdiamond says:
25 Jan 2013, 10:04 pm
Another one against infinities. I argue that the calculus does NOT resolve Zeno’s paradox, among other claims.

“Infinitesimals: Another argument against actual infinite sets”

http://tinyurl.com/b9kn4tb