Physicists found a new quantum paradox that casts doubt on a pillar of reality • Hacker News Board

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#131

Post by jlokier » Mon, Aug 31, 2020, 3:07 AM UTC

Thorentis wrote: post #120

bondarchuk wrote: post #6

The original Wigner's friend paradox: https://en.wikipedia.org/wiki/Wigner%27s_friend The paradox seems to rest on magical thinking about consciousness, and if one simply accepts that a conscious observer can be in a superposition like any other piece of matter, the paradox is resolved. And, from the article: For Wigner, this was an absurd conclusion. Instead, he believed that once the consciousness of an observer be…

From the Wikipedia: > "From the point of view of the friend, the measurement result was determined long before Wigner had asked about it, and the state of the physical system has already collapsed. When now exactly did the collapse occur? Was it when the friend had finished their measurement, or when the information of its result entered Wigner's consciousness?" This to me, shows just how hand-wavy the whole superpos…

> how hand-wavy the whole superposition/quantum collapse stuff really is

Superposition isn't particularly hand-wavy. It's the basis of various technologies, and of precise numerical models we use to build technologies.

Quantum collapse is hand-wavy, and that's because it is not well understood. It might not exist (in which case superposition of mind-states is a thing), or it might exist (in which case mind-states may be definite). Quantum mechanics that we can calculate doesn't give an answer either way, even though it gives lots of other answers very precisely and correctly.

> Wiger doesn't know about it, [...] just seems like silly mind games.

When only applied to a single measurement it does seem like silly mind games, you're not wrong.

The motivation for those thought experiments was to try to reason back from the consequences found from more complex behaviour observed with multiple measurements, back to a simple system with only one measurement.

But when you have many measurements with entanglement, of which there are numerous physical experiements and confirmations by now, the idea that there are just multiple, correlated probabilistic states ready to be observed that we're not yet aware of is not consistent with physically measured behaviours. Those measurements aren't hand-waving, they are hard data, even though my explanation here is hand-waving and doesn't go into it.

> I side with Einstein with his view that everything is already in one state or the other

Numerous experimental results now contradict this view, or require other strange things to be true about the world (for example superdeterminism was mentioned in the article).

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#132

Post by xdarnold » Mon, Aug 31, 2020, 3:10 AM UTC

Thorentis wrote: post #120

bondarchuk wrote: post #6

The original Wigner's friend paradox: https://en.wikipedia.org/wiki/Wigner%27s_friend The paradox seems to rest on magical thinking about consciousness, and if one simply accepts that a conscious observer can be in a superposition like any other piece of matter, the paradox is resolved. And, from the article: For Wigner, this was an absurd conclusion. Instead, he believed that once the consciousness of an observer be…

From the Wikipedia: > "From the point of view of the friend, the measurement result was determined long before Wigner had asked about it, and the state of the physical system has already collapsed. When now exactly did the collapse occur? Was it when the friend had finished their measurement, or when the information of its result entered Wigner's consciousness?" This to me, shows just how hand-wavy the whole superpos…

Your position is more or less defensible, but you will have to accept some compromises to your description of the universe that most physicists find untenable.

Actually, it is Bell's Theorem / Inequality and related experiments that are relevant here. https://en.wikipedia.org/wiki/Bell%27s_theorem

These experiments were really the nail in the coffin for Einstein's position for most physicists. Having to admit non-local hidden variables is a pretty distasteful result.

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#133

Post by stagas » Mon, Aug 31, 2020, 4:31 AM UTC

Zenbit_UX wrote: post #96

rantwasp wrote: post #66

Earlier quoted context omitted.

disagree on the junior dev part and on the god part. what you’re describing is called “simulation theory” and it has been proposed and discussed at length i think lazy evaluation makes sense in that context. i also think that having a few basic rules and after that applying them consistently across your simulation space make sense. if your basic space unit of reality is way smaller than the sims in it can perceive an…

> disagree on the junior dev part and on the god part. Good lord, some people here are definitely on the spectrum. FYI that was an attempt at humor. In case you want to mimic human social behavior in the future: you don't _disagree_ with a joke, you either find it funny or you don't. > what you’re describing is called “simulation theory” and it has been proposed and discussed at length I'm aware of the theory, just l…

> god is a junior dev and no one reviewed his pull requests.

> some people here are definitely on the spectrum. FYI that was an attempt at humor. In case you want to mimic human social behavior in the future ..

_Your_ failed attempt at humour doesn't justify labeling and gaslighting the person who didn't "get it", if anyone can ever consider that to be a joke.

> For the record, I was merely illustrating a point

Illustrating a point or making a joke? In either case, it doesn't justify your "human social behavior" of attacking the personality traits of the person disagreeing with you. My suggestion to you -in the future- accept that someone can have a different opinion and that you could be wrong and try to counteract that without resorting to labeling and gaslighting.

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#134

Post by narag » Mon, Aug 31, 2020, 5:32 AM UTC

lisper wrote: post #124

narag wrote: post #119

Earlier quoted context omitted.

So in your opinion, does this thought experiment can be translated to a "real" experiment now or in a not-so-distant future, like in our lifetimes?

That depends on what you mean. If you mean using a simple system (like a single photon) as a stand-in for Wigner's friend, that has already been done. That's what the OP was about. If you mean using a complex entity like an actual human or an AI that can pass a Turing test, I'll give long odds against.

The later... I ask because every time I read about some thought experiment, it turns out to be an impossible experiment.

In a recent story I asked in general and others told me that there were thought experiments that became proper experiments. But it seems that they were somewhat different, more like pre-experiments. When something gets stuck in the thought experiment category, it's more like a no-experiment.

I have no problem admitting that this kind of ellucubration is useful to anticipate problems. But extracting conclusions from an impossible setup? That's like asking what would happen if an irresistible force meets an immovable object.

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#135

Post by ShamelessC » Mon, Aug 31, 2020, 6:17 AM UTC

Zenbit_UX wrote: post #96

rantwasp wrote: post #66

Earlier quoted context omitted.

disagree on the junior dev part and on the god part. what you’re describing is called “simulation theory” and it has been proposed and discussed at length i think lazy evaluation makes sense in that context. i also think that having a few basic rules and after that applying them consistently across your simulation space make sense. if your basic space unit of reality is way smaller than the sims in it can perceive an…

> disagree on the junior dev part and on the god part. Good lord, some people here are definitely on the spectrum. FYI that was an attempt at humor. In case you want to mimic human social behavior in the future: you don't _disagree_ with a joke, you either find it funny or you don't. > what you’re describing is called “simulation theory” and it has been proposed and discussed at length I'm aware of the theory, just l…

Being patronizing immediately after suggesting people here are on the autism spectrum is kind of insensitive to people who are autistic.

"God is a junior dev", is a mildly funny trope that has existed as long as I've been on the internet. I believe there's an xkcd about it where God says "we hacked most of it together with Perl".

Anyway, it's hard to tell what is and isn't a joke on the internet due to lack of vocal inflection. Maybe consider going easier on people when this happens in the future.

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#136

Post by gonnano » Mon, Aug 31, 2020, 7:24 AM UTC

Thorentis wrote: post #129

incognition wrote: post #126

Earlier quoted context omitted.

QM is not hand wavy and gives precise results for many practical problems. Your theory is wrong as per one of the simplest quantum experiment - the single electron double slit problem.

The variation of the double split experiment that supposedly proves that observance "changes" the outcome, is only a thought experiment, and therefore can be flawed due to incorrect thinking. Obviously, the basic double slit experiment which shows the wave/particle duality of light is done in practice and therefore empirical.

I like most on here have followed your thinking at some point, but have had to ditch our intuition along with comman sense and a good part of our sanity when we found out we were lost down the rabbit hole after schrodinger's cat ate our breadcrumbs.

An observer changing the outcome is a very real repeatable experiment with non wavey results.

https://physicsworld.com/a/do-atoms-going-through-a-double-s...

It's similar to the problem that has been highlighted here by OP, to quote the artical I posted

"Indeed, the results of both Truscott and Aspect’s experiments shows that a particle’s wave or particle nature is most likely undefined until a measurement is made. The other less likely option would be that of backward causation – that the particle somehow has information from the future – but this involves sending a message faster than light, which is forbidden by the rules of relativity. "

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#137

Post by 08-15 » Mon, Aug 31, 2020, 7:54 AM UTC

tsimionescu wrote: post #80

08-15 wrote: post #35

> Take a look at these three statements [...] they cannot all be true Okay, so we have to kill one. The easiest one to kill is > It is possible to make free choices. In other words, quantum mechanics is incompatible with free will. This is clearly shocking to any physicist who believes in Free Will (as defined by philosophers thousands of years ago). But hasn't Free Will been recognized as nonsense for at least two c…

In fact, all statistical experiments, from clinical trials to observations of Bell's Inequality depend on the idea that there exists either free will or true randomness (and that we can base our decisions on that source of randomness). If neither exist, then there is no such thing as statistically independent events, and no way to make statistical observations (since that would imply that your choice of what to measu…

> either free will or true randomness

Isn't unpredictability enough?

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#138

Post by GoblinSlayer » Mon, Aug 31, 2020, 9:18 AM UTC

jlokier wrote: post #130

keymone wrote: post #111

Earlier quoted context omitted.

Sure, just like a thermostat doesn’t experience the feeling of temperature, there is no need for human to feel it, so I understand that we need to explain why is it that we still feel the feeling rather than just observe the signal and react. So why is it wrong to explain this by the necessary recursiveness of predictive modeling that includes modeling “self”? We observe the temperature but we also observe ourselves…

It's only wrong because it's not really an explanation. At best, it's a weak one. Saying that an active model of self "is" what we experience as the consciousness we experience doesn't tell us why we have that experience. We can just as easily imagine a complex machine with an active self-model that isn't conscious, as one that is.[1] So an active self-model doesn't tell us about consciousness. This shows them to be…

Why hard problem is even here? Consciousness isn't magic, because chinese room in conscious, and it has nothing to do with quantum mechanics, because of paradoxes.

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#139

Post by seventhtiger » Mon, Aug 31, 2020, 9:29 AM UTC

tourist2d wrote: post #121

Zenbit_UX wrote: post #61

Whenever I hear about weird shit from the realm of quantum physics (this theory, double-slit, etc..) I can't help but think: Why would I hardcode values for imperceptible objects, that would take an enormous about of ram and cpu time to constantly update values in the off chance it's needed. Much more efficient to optimize for what the _player_ can see at their perspective. Oh and I should probably code in some error…

It could also be that our universe takes up so little resources on "gods" computer ;)

I always wondered about the "computability of the universe" and its compressibility.

If the universe is actually compressible, then object permanence may actually be a trick, like it is in video games. Objects are generated on demand and deleted to save space and processing.

If it's not compressible, which is where I lean, then the full universe must be fully computed every time. No savings can be made, and any delay in computing an object might propagate and cause recalculation cascades for other objects. I lean this way because from my layman's understanding, quantum mechanics act similarly to random seeds, which increases entropy by a lot.

If it's not compressible, then the smallest computer able to simulated the universe is at least as big as the universe itself.

Re: Physicists found a new quantum paradox that casts doubt on a pillar of reality

#140

Post by GoblinSlayer » Mon, Aug 31, 2020, 9:46 AM UTC

kmm wrote: post #57

bondarchuk wrote: post #6

The original Wigner's friend paradox: https://en.wikipedia.org/wiki/Wigner%27s_friend The paradox seems to rest on magical thinking about consciousness, and if one simply accepts that a conscious observer can be in a superposition like any other piece of matter, the paradox is resolved. And, from the article: For Wigner, this was an absurd conclusion. Instead, he believed that once the consciousness of an observer be…

We're veering away from physics here, but isn't consciousness actually quite "magical". It's beyond remarkable to me that stimulating nervous tissue, composed of quite mundane things like protons and electrons, yields a subjective experience. I know many people reject the hard problem of consciousness, but to those who don't, the implications of thought experiments like Wigner's friend, like superpositions or entangl…

>Coming back to physics, there's an assumption you and other commenters are silently making, which is that quantum mechanics is even applicable to macroscopic objects like humans.

It follows from schrodinger equation, it provides no exception for macroscopic objects. You can say quantum effects indeed happen at the lowest level, and macroscopic behavior follows what happens at the lowest level. It's a question of reducibility.

> The largest objects which have been shown to act wave-like are a few thousand atoms large.

Large objects have wave-like behavior, e.g. you can't determine their size with femtometer resolution, they don't suffer from ultraviolet catastrophe and have macroscopic quantum effects like superconductivity.