Philosophy Discussion Forums | A Humans-Only Club for Open-Minded Discussion & Debate

[A_Seagull]

I think the interesting philosophical question following the implications of quantum interpretation is :

Does randomness exist as a vital ingredient in the nature of the universe alongside mass, space, time , electromagnetic force etc.?

I do not know the answer to that question.

[Bohm2]

I think the interesting philosophical question following the implications of quantum interpretation is : Does randomness exist as a vital ingredient in the nature of the universe alongside mass, space, time , electromagnetic force etc.? I do not know the answer to that question.

A priori, one cannot exclude the existence of some hidden variables (not described by the usual form of QM) that provide a deterministic cause for all seemingly random quantum phenomena. For me the interesting question is what is the nature of quantum non-locality? What is responsible for the EPR correlations. I mean how does nature do that 'trick'?

[A_Seagull]

I think the interesting philosophical question following the implications of quantum interpretation is : Does randomness exist as a vital ingredient in the nature of the universe alongside mass, space, time , electromagnetic force etc.? I do not know the answer to that question.

A priori, one cannot exclude the existence of some hidden variables (not described by the usual form of QM) that provide a deterministic cause for all seemingly random quantum phenomena. For me the interesting question is what is the nature of quantum non-locality? What is responsible for the EPR correlations. I mean how does nature do that 'trick'?

I am not quite sure what you mean by ' a priori' , I suspect that you mean 'logically' or 'rationally'.

I agree that the question of the rationalising of quantum weirdness is most interesting. I suspect that the answer, if indeed there is an answer, will lie in a re-evaluation of what is meant by time, space, mass, causality etc.

For it may be that it is not nature doing any sort of trick, but rather it is our perception of it which makes it seem like a trick.

[Bohm2]

I am not quite sure what you mean by ' a priori' , I suspect that you mean 'logically' or 'rationally'.

I mean we can't assume that QM is the final true theory.

I agree that the question of the rationalising of quantum weirdness is most interesting. I suspect that the answer, if indeed there is an answer, will lie in a re-evaluation of what is meant by time, space, mass, causality etc. For it may be that it is not nature doing any sort of trick, but rather it is our perception of it which makes it seem like a trick.

Yes, quantum correlation can be explained by non-locality but it's very hard for us to conceptualize how non-locality can occur. That's why many physicists prefer non-realism or instrumentalism as an alternative interpretation. Even physicists who hold that violation of Bell's inequality necessitates non-locality, describe such non-local correlations as somehow coming "outside" of space-time:

To put the tension in other words: no story in space-time can tell us how nonlocal correlations happen, hence nonlocal quantum correlations seem to emerge, somehow, from outside space-time.

Quantum nonlocality: How does Nature perform the trick?
http://lanl.arxiv.org/pdf/0912.1475.pdf

If so, whatever causes entanglement does not travel from one place to the other; the category of “place” simply isn't meaningful to it. It might be said to lie *beyond* spacetime. Two particles that are half a world apart are, in some deeper sense, right on top of each other. If some level of reality underlies quantum mechanics, that level must be non-spatial.

How Quantum Entanglement Transcends Space and Time
http://www.fqxi.org/community/forum/topic/994?search=1

Some models try to model entanglement/non-locality by suggesting wormholes, adding hidden dimensions, etc. For an interesting discussion on this:

So here’s my proposal: can we construct a finite geometry, preferably in (3+1) dimensions, that is also non-local and that, via coarse-graining (or some other method), is locally curved? In other words, this geometry would be, in some limit, equivalent to the geometry of general relativity, but in some other limit, would allow for the non-locality of certain quantum states and, perhaps in the process, make entanglement less mysterious.

Entanglement and non-local, finite geometry
http://quantummoxie.wordpress.com/2012/ ... -geometry/

'Spooky action' builds a wormhole between 'entangled' quantum particles
http://www.sciencedaily.com/releases/20 ... 161549.htm

The holographic dual of an EPR pair has a wormhole
http://arxiv.org/pdf/1307.1132v2.pdf

As an aside, there are other ways to model entanglement without requiring wormholes, adding hidden dimensions, etc. but they involve going beyond QM. For example:

A Classical Framework for Nonlocality and Entanglement
http://arxiv.org/pdf/1210.4406.pdf

"Systemic Nonlocality" from Changing Constraints on Sub-Quantum Kinematics
http://arxiv.org/pdf/1303.2867v1.pdf

Brownian Entanglement
http://arxiv.org/pdf/quant-ph/0412132v1.pdf

[The Truth]

I have a question concerning MWI, but it's open to those of any and all interpretative persuasions.

If I take a typical coin, which has an equal likelihood of coming up heads or tails, and I flip the coin. Then if my understanding of MWI is correct I should end up with two universes, one in which the coin comes up heads, and one in which it comes up tails. This seems simple enough.

But let's say that the coin also has a one in a million chance of ending up standing on its edge. Now if I flip the coin, what will happen? With every flip of the coin, shouldn't I get one universe where the coin comes up heads, one where it comes up tails, and one where it ends up standing on its edge? After all, there is a non-zero probability that the coin will end up on its edge on any flip. So wouldn't I end up with just as many universes where the coin ends up standing on its edge, as I do universes with the coin either heads or tails? Every time I flip the coin, shoudn't all three outcomes actually occur? Thus no possible outcome would ever occur more often than any other possible outcome.

So where does probability come from? No outcome can ever be said to occur more often, because every outcome will occur, every time. I may be more likely to see some outcomes than others, but that doesn't mean that they occur more often, just that I see them more often.

But then how does MWI account for probability?

[A Poster He or I]

To The Truth,

Regarding MWI, I have never read Everett's original thesis, but am familiar enough with MWI from numerous popular science books, and the writings of a couple of physicists who lean toward MWI. To me, it seems very evident that probability does not exist in MWI. It can't exist because every possibility actually occurs with 100% probability. Moreover, there are not 3 possible universes created from your coin flip; there are quintillions upon quintillions upon quintillions, because you cannot talk about the coin or the flip when considering the outcomes. You have to talk about the quanta comprising the coin, the quanta comprising the air molecules it encounters as it moves through the air, the quantum interactions associated to the breakdown of adenosine triphosphate molecules in every cell of your body that went into providing the energy to flip that coin, AND on top of all it, how every one of those interactions were affected by every preceding interaction that rendered each quantum into its specific quantum state at the moment of interaction.

It is true that in those untold quintillions of outcomes, there are 3 final states possible for the coin after the flip, but there are many, many, many more than just 3 resulting universes.

[Bohm2]

Thus no possible outcome would ever occur more often than any other possible outcome. So where does probability come from? No outcome can ever be said to occur more often, because every outcome will occur, every time. I may be more likely to see some outcomes than others, but that doesn't mean that they occur more often, just that I see them more often. But then how does MWI account for probability?

I don't believe MWI has adequately addressed this question. Wallace tries to answer the question in this paper (and a few others) but I don't think he succeeds (see critical papers below):

The Quantitative Problem of probability in the Everett interpretation is often posed as a paradox: the number of branches has nothing to do with the weight (i. e. modulus-squared of the amplitude) of each branch, and the only reasonable choice of probability is that each branch is equiprobable, so the probabilities in the Everett interpretation can have nothing to do with the Born rule... As such, the ‘count-the-branches’ method for assigning probabilities is ill- defined. But if this dispels the paradox of objective probability, still a puzzle remains: why use the Born rule rather than any other probability rule?...But it has been recognised for almost as long that this account of probability courts circularity: the claim that a branch has very small weight cannot be equated with the claim that it is improbable, unless we assume that which we are trying to prove, namely that weight=probability...The second strategy might be called primitivism: simply postulate that weight=probability. This strategy is explicitly defended by Saunders; it is implicit in Vaidman’s “Behaviour Principle”; It is open to the criticism of being unmotivated and even incoherent... The third, and most recent, strategy has no real classical analogue ... This third strategy aims to derive the principle that weight=probability from considering the constraints upon rational actions of agents living in an Everettian universe. It remains a subject of controversy whether or not these ‘proofs’ indeed prove what they set out to prove.

The Quantum Measurement Problem: State of Play
http://arxiv.org/abs/0712.0149

See these two 2013 papers as to why many are sceptical that MWI relying on rational agents or anything of that sort discussed by Wallace provide a reasonable answer:

Against the Empirical Viability of the Deutsch-Wallace-Everett Approach to Quantum Mechanics
http://philsci-archive.pitt.edu/9541/1/ ... rchive.pdf

Many Worlds: Decoherent or Incoherent?
http://philsci-archive.pitt.edu/9542/1/ ... rchive.pdf

[Raymond]

In the MWI a measurement of a 0.1-0.9 superposition gives the same outcome as the 0.0-0.5 outcome. But think about it. What do the numbers mean?

The only viable theory is the hidden variable deterministic approach. Empty non-deterministic chance is...well...vacuous.

[pavsic]

Concerning the interpretaion of quantum mechanics, we are like blind people investigating an elephant. Somebody touches his legs and says: “It is like a tree”. Another one examines its nose and claims: “It is a sort of snake”. Etc. In fact all those statements reveal a property of the elephant, in this sense they were all true. The analogous holds for the diverse interpretations of quantum mechanics. Each reveals a part of the true nature of quantum mechanics. What is lacking is an overall view, a crucial insight about what QM is actually describing.

Some people say that the wave function ψ, the central mathematical object of QM, represents only a formal expression of agents’ degrees of belief, i.e. their available knowledge, about a certain experimental situation.

This view about the nature of ψ implies that the dynamical process described by the Schrödinger’s Equation –the central mathematical equation of QM--provides solely the evolution of the probabilities in the agent’s mind. Hence, there is no motion of quantum objects in spacetime.

To others this is unacceptable, because –as they say--wave function then does not refer to anything real in the world. They insist that QM should describe ---and that it does describe--- the behavior of objectively existing objects moving in a real space.

See the last, non technical, part of this book as to how the Copenhagen and the Everett interpretation are not incompatible, but complement each other, each one reveals a part of the overall picture:

The Landscape of theoretical physics: A Global view. From point particles to the brane world and beyond, in search of a unifying principle (Kluwer, 2001) that is also posted on arXiv.

A popular discussion is in the book "The grand biocentric design" (BenBella, 2020).

[Lagayascienza]

I go with MWI. I've not read Everett in the original, only what has been said of the MWI in the many popular science books I've read, and a few physics papers. But I like the ideas of Sean Carroll and David Deustche who both argue in their books for the MWI. It seems like the most straightforward interpretation to me although, admittedly, this clarity is achieved at the expense of having to posit gazillions of other universes branching off at every instant. But, then, none of the interpretations of QM are problem-free.

[Sculptor1]

QM is a set of theories which do not yet "save the appearances". I tend to favour the most economic and Okham-like ideas, but as yet, we aint got it figured out.

PS. It is an absurdity to suggest that QM can validate "free will" as some try to argue. It does not.

Just because understanding the causes is difficult, does not mean that things are uncaused. It just means humans are not yet up to the job of making a decent enough model to describe what is goin on.

I think part of the problem is that we are trying to explain, when we can ever do, ultimately is describe. and science is decriptive at its best.