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Parable of Alien Chess

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Re: Parable of Alien Chess

#101

Post by GistNoesis »

jackhalford wrote: post #45
konschubert wrote: post #39

Earlier quoted context omitted.

I still haven't understood why people keep saying that there is randomness in QM. The so-called "wave function collapse" isn't really part of QM, it's duct tape that we have applied to stick together the QM with "Classical Physics" and our pre-existing assumptions about human consciousness. I don't think we should consider it "real" or "true". Without the wave function collapse, there is no randomness in QM.

you have it wrong, QM is the only physical theory that has randomness as an inherent part, as compared to e.g thermodynamics where randomness is due to lack of information. It is proven (see Bell inequalities) that randomness in QM isn't due to lack of information. You can't just wave away the collapse mechanism, what do you make of the double alit experiment? isn't the target "real" enough?

What is usually misunderstood about QM is that QM isn't a model of the world.

QM is a model of "what we can observe from the world" based on "what we can observe from the world".

QM is a model of "accessible" information.

What laymen usually wants is to understand how the world evolve.

What QM physicists tell them is there exist some inaccessible information, but using accessible information we have, we know how to predict all the accessible information (albeit stochastic-ally).

The typical example to help computer scientists to understand is the seed of a pseudo-random generator in an online casino. The players will never be able to access the seed, therefore the best they can do is make decision based on the value of the generated random numbers they observe and their probabilities.

Bell inequalities are a consequence of this modelisation. They are a refurbishing of Boole's inequalities, a theorem about probability which only bound those who use probability.

The usual fallacy forward is telling QM is a non-local theory, classical local theory can't violate Bell inequalities, Bell inequalities violations are observed in the real world, therefore the world is not local...

Re: Parable of Alien Chess

#102

Post by simonh »

lmm wrote: post #42
simonh wrote: post #11

Earlier quoted context omitted.

That's the question the article is addressing. I think you're putting too much weight on the rough and sketchily defined example and missing the actual topic.

But the claim lives or dies by its example. The author's whole point is that he's discovered or imagined a situation in which doing science "badly" would be better than doing it "well". If his imaginary situation doesn't actually hold up then his whole argument is nonsense.

Analogies are simply tools to facilitate discussion, they can't themselves say anything definitive about the underlying claim. That's why it's useful to interpret them generously. If I came up with a flawed analogy for time dilation would that show that time dilation is nonsense?

I think a better approach on encountering a flawed analogy is to attempt to improve it, come up with a better one, or address the underlying claim directly, but saying "this analogy is unclear to me the end" isn't going to get you very far in life.

Re: Parable of Alien Chess

#103

Post by js8 »

scandox wrote: post #46
laumars wrote: post #40

Earlier quoted context omitted.

No, a touch over 100 years ago Einstein came up with a new set of equations that more precisely describes the movement of objects. Newtonian physics is still valid and still taught at schools since it adequately explains the movement of objects at an approximate level that is good enough for most people most of the time. But when dealing with equations at an astronomical scale, Newtonian physics start to break down.…

Complements it

I think you misunderstand. The work that Einstein did on quantum mechanics was indeed "complimentary", i.e. provided for free as a courtesy. (Although it could be argued he actually got paid for it later with Nobel prize.)

Re: Parable of Alien Chess

#104

Post by Jweb_Guru »

eigenket wrote: post #97
Jweb_Guru wrote: post #63

Earlier quoted context omitted.

The Everett/Many Worlds interpretation cannot reproduce the predictions of quantum mechanics without extra assumptions (e.g. the Born rule) that don't have any physical basis within the context of MWI.

I am not aware of any interpretation that has the Born rule without assuming something equivalent to it. For example de Broglie–Bohm theory requires you to assume the original distribution of the particles follows the Born rule. QBists just postulate it, consistent histories just postulates it etc. I am not particularly a many-world proponent, but I do not think it is fair to level this accusation as an issue for man…

AFAIK it can in fact be derived through Gleason's Theorem under the assumption of noncontextuality, so I don't think it's fair to say that nobody can derive the Born rule without assuming it (many people have issues with noncontextuality but that's very much a philosophical thing). The thing you have to demonstrate is that a probability measure actually connects to physical observables in some way, and this is the part that is difficult (and as far as I can tell MWI does nothing to resolve this conundrum).

Re: Parable of Alien Chess

#105

Post by Jweb_Guru »

ibab wrote: post #73
Jweb_Guru wrote: post #63

Earlier quoted context omitted.

The Everett/Many Worlds interpretation cannot reproduce the predictions of quantum mechanics without extra assumptions (e.g. the Born rule) that don't have any physical basis within the context of MWI.

Yes, you are right to point this out. There are some important details that are still being debated. Personally my impression is that the debate has advanced enough to the point where MWI can’t be outright dismissed based on this argument. There are multiple plausible explanations and the remaining difficulties have more to do with philosophy than physics. Edit: To give one example of an approach that I think is prom…

While I intuitively like the statistical approach you mention, under it the Born rule holds only approximately, so it should be theoretically possible to observe entangled states which we have never done--i.e. it produces different predictions from the Copenhagen interpretation of quantum mechanics, which means it's not strictly a different interpretation, but its own falsifiable theory. Like I said in another comment, if we ever do observe entangled states directly, people will jump on board one of these alternate explanations like lightning. But until we do, the question of why we never ever observe anything that doesn't look like collapse still needs mathematical justification.

Re: Parable of Alien Chess

#106

Post by tiborsaas »

subroutine wrote: post #74
slx26 wrote: post #52

Earlier quoted context omitted.

Observing the movement of pieces quickly reveals that the board is divided in 64 squares. Squares being black and white or any other set of colors is actually irrelevant. They can basically fully understand the game from this, no need to make things complicated.

I'm not sure they would be able to infer the board has 64 squares. They can't see the board, and can only see the locations of the starting pieces and location of the first move. The center of the board could be anything - 300 hexagons, a spin-wheel, series of mouse traps, etc. Here's my interpretation of what they see pre- and post- opening move... PRE: https://i.ibb.co/s6WnPNV/Chess.png POST: https://i.ibb.co/7pg7G…

This is a fun one, thanks for the illustration.

If you analyse 5000 board configurations you can deduce with a high certainty that there are 64 fields the pieces can be on.

The pressing question is then why can some pieces move only diagonally or only in one direction or any.

In the case of chess, going after the why question is pointless, but obviously that wouldn't satisfy any scientist: It works because someone decided that it should work like this.

Could it work with different rules? The alien scientist then probably opt for a positive answer calling for a multiverse of chess rules :)

Re: Parable of Alien Chess

#107

Post by chrisweekly »

js8 wrote: post #103
scandox wrote: post #46

Earlier quoted context omitted.

Complements it

I think you misunderstand. The work that Einstein did on quantum mechanics was indeed "complimentary", i.e. provided for free as a courtesy. (Although it could be argued he actually got paid for it later with Nobel prize.)

IMHO that interpretation is implausible. "... [theory] doesn't replace, rather [[its creator] provided it for free]"? makes no sense.

It doesn't replace, rather complements it.

Occam's razor AND semantics.

Edit: maybe you were joking? in which case sorry (it missed the mark)

Re: Parable of Alien Chess

#108

Post by eigenket »

Jweb_Guru wrote: post #104
eigenket wrote: post #97

Earlier quoted context omitted.

I am not aware of any interpretation that has the Born rule without assuming something equivalent to it. For example de Broglie–Bohm theory requires you to assume the original distribution of the particles follows the Born rule. QBists just postulate it, consistent histories just postulates it etc. I am not particularly a many-world proponent, but I do not think it is fair to level this accusation as an issue for man…

AFAIK it can in fact be derived through Gleason's Theorem under the assumption of noncontextuality, so I don't think it's fair to say that nobody can derive the Born rule without assuming it (many people have issues with noncontextuality but that's very much a philosophical thing). The thing you have to demonstrate is that a probability measure actually connects to physical observables in some way, and this is the pa…

Gleason's theorem also makes a big assumption when you require that the measurement outcomes are associated with POVM elements (or projection operators if you don't like POVMs). I lumped that in with "assuming something equivalent to it" since Gleason's theorem (at least by my understanding) is exactly the statement that assuming non-contextuality+POVMs/POMs is equivalent to assuming Born's rule.

Although its really cool I don't think Gleason helps you tie any particular interpretation to the Born rule, since you still have to make a jump to tie your measurement outcome to a POM/POVM element.

As far as your last sentence goes, this is sort of what I was trying to argue in my comment above. The "part that is difficult" that you identify as being unresolved by MWI is also completely unresolved by pilot wave theory, or qbism or consistent histories or any other interpretation (as far as I am aware).

Re: Parable of Alien Chess

#109

Post by Jweb_Guru »

eigenket wrote: post #108
Jweb_Guru wrote: post #104

Earlier quoted context omitted.

AFAIK it can in fact be derived through Gleason's Theorem under the assumption of noncontextuality, so I don't think it's fair to say that nobody can derive the Born rule without assuming it (many people have issues with noncontextuality but that's very much a philosophical thing). The thing you have to demonstrate is that a probability measure actually connects to physical observables in some way, and this is the pa…

Gleason's theorem also makes a big assumption when you require that the measurement outcomes are associated with POVM elements (or projection operators if you don't like POVMs). I lumped that in with "assuming something equivalent to it" since Gleason's theorem (at least by my understanding) is exactly the statement that assuming non-contextuality+POVMs/POMs is equivalent to assuming Born's rule. Although its really…

I think we're in agreement there (though IMO it's highly nonobvious that noncontextuality+POVMs automatically get you the Born rule, so I don't think it's "cheating" to assume that--obviously any set of axioms that let you derive Born will have such a property!). I was mostly saying, I don't think MWI helps us understand where the probabilities come from any more than any other interpretation--you need something more. And if you can't identify where the probabilities come from, then saying your theory is "deterministic" rings fairly hollow to me.

Re: Parable of Alien Chess

#110

Post by leto_ii »

tpoacher wrote: post #93
leto_ii wrote: post #19

I suspect the metaphor is inspired by Feynman's one about gods playing chess [1]. As it's almost always the case, Feynman manages to immediately inspire and illuminate. On the other hand, the present article seems to me to get some important things wrong. For one, it's not the case that overall white and black win 50% of the time each. More importantly though, if somebody is interested in investigating chess, they wi…

Effectively what you're saying is that you cannot possibly entertain the larger point of the article, because you find faults with the specific analogy he chose to illustrate it. Right? Fair enough. His fault for trying to argue using an analogy I guess. It never works.

That's precisely the opposite of what I was saying. I tend to agree with what (I understood as) the larger point of the article, I just see the chess analogy as muddled and inaccurate.
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