Well, I distinctly recall reading the consensus part on a page I have yet to remember...
Given what you wrote, sounds like Less Wrong. Eliezer Yudkowsky announced that MWI is correct for reasons that, from a physicists point of view, don't hold any real weight. I'm also pretty sure he gets his maths completely wrong on two occasions, not really showing any actual understanding of quantum mechanics (an inherently mathematical subject) while dismissing quantum physicists as blinded by orthodoxy. MWI still has a number of problems while not offering any real positive benefits.
I really need to write a hell of a lot about both quantum mechanics and philosophy of science (and am tempted to do both) to even make the fundamental points about this debate, but I can make some broad claims here and hopefully they won't be taken the wrong way.
1) Most physicists use Copenhagen interpretation language but broadly subscribe to the
shut up and calculate (SUAC) (not to be mistaken for the
extreme SUAC which is a form of the
Mathematical Universe Hypothesis (MUH) and can safely be ignored for now) school of thought, where the interpretation of what the equations of quantum mechanics
mean is utterly irrelevant to the actual equations themselves. Any valid and complete interpretation of QM
must give the same empirical and mathematical results, so what interpretation you subscribe to simply changes the language you use to refer to each feature. Copenhagen happens to be the easiest language to comprehend and teach in for most people, being only strongly counter-intuitive. MWI requires a massive mental shift and introduces a number of major pitfalls (not least confusing MWI with multiverse concepts)
as well as being strongly counter-intuitive. I will say that MWI actually has a couple of areas it (slightly arguably) becomes a better language for talking about ideas in (quantum cosmology and computation/information, although these are also the areas with more advocates so part of that might just be it's the native language and it is far from required for either), but you really need to make sure you have gotten whoever you are talking to past those pitfalls and that they aren't mistaking it for an intuitive idea.
2) MWI does not, in my book, actually get rid of any of the problems of the Copenhagen interpretation in a convincing or satisfying manner. All of them are present in other forms (eg, world splitting vs waveform collapse). In fact it makes at least the measurement problem into a pretty well lethal issue; the nature of probability and derivation of the Born rule. Broadly speaking if you get rid of measurement you get rid of probability and have to re-insert it somehow. The attempts to do so have been broadly unconvincing and/or have often introduced new flaws or gross modifications to the physics (otherwise unphysical modifications to Schrödinger's equation...). Without a valid description of probability MWI is effectively an incomplete description of quantum mechanics, making it less valuable than more grossly philosophically troubling interpretations if you value such things.
3) Related to 2, MWI can actually describe a range of universes. Not talking about multiple worlds here, but rather families of universes. Think of it as the different possible configurations of dimensions in M-theory. There are a vast number of ways you can arrange such dimensions and each gives you a different physics. Some tiny subset describe universes where the physics is similar to ours. There is no absolute reason to privilege this subset, let alone any specific configuration. The only current reasoning we would see such physics from M-theory is anthropic and not wholly satisfactory without introducing extra ideas (birthing universes within a multiverse for example) to justify such an anthropic principle of universes.
The range of universes MWI can describe is related to the probability functions again. I have seen no convincing way of introducing probabilities that doesn't have some arbitrary basis for those probabilities, usually meaning you have to front-load the theory to get the right answers out (select the right geometry of dimensions to get our physics). This is similarly unsatisfactory and still doesn't solve all the probability issues IMO.
4) The nature of MWI from a philosophical point of view is kinda complicated and confused. It is, in a sense, a naive realist interpretation; the formal mathematical description of the wavefunction is taken to be an exact and physical description of reality. This is sometimes given as a definition of MWI from both critics and advocates. Yet it does not hold the same philosophical values as other scientific realist descriptions (Bohmian mechanics, etc) which have significant things to say about realism vs locality, etc. MWI is often regarded as philosophically uninteresting in this regard, completely outside the realm of the ideas that can actually be explored within such debates or have influence on them in turn. Even when philosophical conclusions are drawn from it they are far from either required by or unique to the theory.
This is particularly significant because some of these philosophical debates are deeply intertwined with the evolution of quantum physics. The investigations into Bell's theorem are fundamentally philosophical but can be conducted using an optical table, laser, some mirrors and a lot of smarts. Spending time on non-MWI interpretations can lead to such investigations which return objective value. I don't see much value coming from MWI in this sense.
OK, I've spent quite a while on this and I'm still not satisfied with it. I think these points hold, although they could do with tightening up and refining somewhat (not to mention references out the wazoo), but I'm just going to post this and see what happens.
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Topic: Atheism/Religion Discussion (Read 181449 times)