And the Winner is... Many-Worlds!

post by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2008-06-12T06:05:33.000Z · LW · GW · Legacy · 12 comments

This is one of several shortened indices into the Quantum Physics Sequence.

Macroscopic quantum superpositions, a.k.a. the "many-worlds interpretation" or MWI, was proposed in 1957 and brought to the general attention of the scientific community in 1970.  Ever since, MWI has steadily gained in popularity.  As of 2008, MWI may or may not be endorsed by a majority of theoretical physicists (attempted opinion polls conflict on this point).  Of course, Science is not supposed to be an opinion poll, but anyone who tells you that MWI is "science fiction" is simply ignorant.

When a theory is slowly persuading scientists despite all academic inertia, and more and more graduate students grow up familiar with it, at what point should one go ahead and declare a temporary winner pending new evidence?

Reading through the referenced posts will give you a very basic introduction to quantum mechanics - algebra is involved, but no calculus - by which you may nonetheless gain an understanding sufficient to see, and not just be told, that the modern case for many-worlds has become overwhelming.  Not just plausible, not just strong, but overwhelming.  Single-world versions of quantum mechanics just don't work, and all the legendary confusingness and mysteriousness of quantum mechanics stems from this essential fact.  But enough telling - let me show you.


Comments sorted by oldest first, as this post is from before comment nesting was available (around 2009-02-27).

comment by Thanatos_Savehn · 2008-06-12T06:46:23.000Z · LW(p) · GW(p)

So Schrödinger's cat has experienced all possible states of its "existence"? And Schrödinger's decision was the same throughout the many worlds? Is his decision then an indicia of his soul?

comment by Schroedinger's_Ghost · 2008-06-25T00:45:37.000Z · LW(p) · GW(p)

I must say, NO...

If Bohm had come first, CI/MWI both crackpot theories wouldnt have seen daylight, which would be best. MWI rejects existence of anything, it states your just deluded to believe thigns happen, when in reality nothing ever happens at all except everything all at ones. So when you make love to your wife tonight, that's just a delusion, cause at the same time u strangle her to death, sell her on ebay, etc. the very same sec, ur consciousness is just deluded to believe you make love to her.


comment by Mitchell_Porter · 2008-09-27T13:12:00.000Z · LW(p) · GW(p)

I have been directed to a new, very short paper from Frank Tipler, "Testing Many-Worlds Quantum Theory By Measuring Pattern Convergence Rates", in which we have yet another alleged experimental test for MWI. Specifically, Tipler thinks he can derive the Born probabilities. He starts by distinguishing between the idealized asymptotic scatter of infinitely many measurements (say, in the double-slit experiment) and the growing actual pattern of always-finitely-many measurements, and then uses Bayes to say something quantitative about the rate at which the former approximates the latter. Without having examined the argument in any depth, I am going to predict that if it holds up, it will be possible to reproduce it within a non-MWI framework (e.g. standard quantum measurement theory). But Bayesian many-worlders may wish to look at the details.

comment by Mitchell_Porter · 2008-09-27T13:12:50.000Z · LW(p) · GW(p)

rate at which the latter approximates the former, I mean

comment by edo · 2011-11-21T06:18:08.236Z · LW(p) · GW(p)

ok I've another proposition, think about another world whenever you find one noble laureate who actually subscribes to the view above outlined, I've contacted at least 6 nobel laureates of which all rejected it, I give you 10 dollars for every nobel laureate who subscribes to it, and I get one dollar for every nobel laureate who rejects it, deal?

comment by edoradiohead · 2011-11-21T14:24:16.996Z · LW(p) · GW(p)

karma police, arrest this man his proposition, is making me feel ill, and i want to belie-ie-ieve

karma police, arrest 't hooft, and polizer, they making it seem, like i'm na-ie-ie-ieve

this is way you get (2x) when you mess with worlds,

quantum police, I've given 50 years it's not enough, to make a little sense of Everret's multiverse

This is what you get(2x) of many-worlds

Fiew for the mwi, I lost myself (2x) Fiew for crackpottery, I lost myself (2x)

comment by edoradiohead · 2011-11-21T14:46:54.025Z · LW(p) · GW(p)

oh yeah and arrest smooth, and even gell-man and leon cooper while you're at it

comment by edoradiohead · 2011-11-21T15:26:44.592Z · LW(p) · GW(p)

karma/quantum police was very active today

comment by edoradiohead · 2011-11-24T09:07:21.815Z · LW(p) · GW(p)

a new crackpot-index!:

1- a physicist who promotes his own views in books, and blaming the unpopularity of his view on the amount of crackpots in physics 2- someone who gives a clearly false image of the reception of a theory 3 - someone who hasn't got a proper education on physics, calling the majority of physics crackpots 4- someone who thinks 'science' itself isn't the best method for science 5- someone who postulates very big ideas, and says he doesn't need observations to prove it 6 - someone referring to 'in the future' we may have these observations, as a proof

comment by Grognor · 2012-03-10T20:57:00.995Z · LW(p) · GW(p)

I happened upon the website of a Norwegian physicist named Kim Øyhus who independently came to the many-worlds conclusion in 1990. The page strikes me as an unusually good example of epistemic rationality. He starts from a premise ("if the math of quantum mechanics is true,") and moves onto four hypotheses (which cover all possible states of reality, since the fourth hypothesis is, "something else"), figures out testable predictions of each hypothesis, and comes to the conclusion that the Many-Worlds Interpretation is correct.

Replies from: n4r9
comment by n4r9 · 2015-04-15T11:03:17.290Z · LW(p) · GW(p)

As far as I can tell, all he does in his experiment is label one of a pair of electrons as the "Observer" and exclaim that Many-World has been proven because this "Observer" electron enters into a superposition with the other electron. The problem is that literally every other interpretation of quantum theory would make the same predictions for this experiment, however you label the electrons.

comment by Stabilizer · 2012-04-14T20:07:10.715Z · LW(p) · GW(p)

“Despite the unrivaled empirical success of quantum theory, the very suggestion that it may be literally true as a description of nature is still greeted with cynicism, incomprehension, and even anger.”

-David Deutsch (As seen on Cosmic Variance)