221–230 of 356 posts
Couldn't that 'hidden variable' be just another dimension? So while those particles might have been separated in space by a large distance, on that fifth dimension they haven't moved and are still sitting side by side.
I'll never understand entanglement. Every explanation makes me wonder why it can't be used to instantaneously send a message. I never fully understand the explanations why it can't be used to do so. I don't understand how you can be sure about the state of the other particle, what if someone already measured it and then did something to it?
Imagine you have a pouch with a red and a blue marble in it, then take out a marble without looking at it and hand the pouch to a friend. Later, if you look at your marble, you instantly have information about the other marble at a speed greater than the speed of light... but you couldn't use that fact to send a message. The only difference in quantum physics is that there are actually two parallel universes: One in…
What exactly does it mean? This sentence always feel like as if these particals are sentient beings and can react to when someone sees them.
If observing means performing an experiment and finding out is this information, that an experiment to observe the actual state has been performed, sent to the other half? To know the state of other half another experiment had to be carried out on it.
How is it any different from picking randomly from a set of pairs? We won't know what other half is until one of them is observed.
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That's not a bad analogy, but you have to be very careful here because no classical analogy can be a perfect fit for entanglement. The wave function is deeply and fundamentally different than our classical reality, and there is no way to reproduce its behavior classically. Among the fundamental differences is the fact that classical information can be copied but quantum states cannot be cloned. This is IMHO the singl…
A classical analogy for entanglement: suppose I have two balls in a bag. They are identical in every way, except one is red and the other is blue. I randomly grab one in each hand and show my hands closed. Now the states of the ball are entangled: as soon as you see the color of one ball, that "determines" the color of the other. (Not claiming that this is a perfect analogy, but I don't see where it diverges from how…
If I look through the holes, I will see that one ball is blue and the other is red.
If I touch them through the holes, I will feel that one ball is hot and the other is cold.
However, I cannot look and touch at the same time. And once I check the color or the temperature of one of the balls (so I know it for both) the link is broken.
If I look first, I’l see that one is red and the other is blue. But if now I touch them, each one will by hot or cold with 50/50 probability. Finding the temperature of one doesn’t tell me anything bout the temperature of the other. And when I touch a ball I don’t know its color anymore: if I look at it again it could be red or blue with 50/50 probability.
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It could also be that we simply don’t understand something about light phase, and that’s causing us to get confused about superpositions. After all, the experiments aren’t on single photons, they are on beams of photons.
Not sure if we're confusing threads here - double slit experiments have been run on single photons and the results are pretty conclusive. Even a single photon is a wave that interferes with itself. I would expect similar here. Intuition is terrible at understanding what is going on at the atomic and smaller level, or anywhere relativistic anything is happening.
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The distinction between "adding" and "removing" a postulate is an important, non-arbitrary one. The "worlds" are there in both theories; Copenhagen adds a new phenomenon (non-unitary evolution) which makes some of them disappear at unspecified times. The "worlds" are direct consequences of suppositions shared with Copenhagen . Many worlds has N postulates, Copenhagen has no fewer than N+1. One theory is a strict subs…
I think it is not as simple as counting the number of postulates. The ultimate arbiter is physical reality and that decides whether removing or adding postulates is what brings you into agreement. The fact that the quantum state in some equation before wave function collapse looks like many worlds say nothing whether you should take this at face value or whether you are missing an additional postulate that gives you…
> Yes, it gets rid of the collapse postulate, but no, it actually introduces many worlds. [...] but in the end many worlds makes a metaphysical claim that two cats exist, [...] while Copenhagen claims only one cat exists in the end.
If you are saying that many worlds makes a greater number of claims than Copenhagen, that's incorrect, as explained above. The claims made by many worlds are a strict subset of Copenhagen.
If you are claiming that many words "introduces" the worlds but Copenhagen does not, that's also incorrect, because the worlds (it seems we agree) are also there in Copenhagen. If they weren't, there would be nothing to "collapse" in the first place!
If you're not saying one of those things, then I'm not sure what that paragraph is trying to say.
> But just because it is an additional postulate it does not per se make many worlds the better theory
It absolutely does, given that both agree equally well with observation.
Each additional assumption in a theory is an opportunity to be wrong. Therefore, given two theories which are in agreement with observation, the theory with fewer unchecked assumptions has a higher probability of being right.
A theory which disagrees with observation (like your altered relativity example) has zero percent chance of being right, so those kinds of examples aren't applicable.
This is just a somewhat more rigorous way of explaining why Occam's Razor is so effective.
For example, take [the dragon in Sagan's garage][1]. We have two models of reality: A garage containing (a) a dragon, who is (b) invisible, (c) dodges touch, (d) floats in air, (e) gives off no heat (f) etc, etc. Or we have a world/garage where none of those things are true.
Both models agree with observation— any measurement we make will not contradict either "empty garage" or "undetectable dragon". And yet one of them is a better theory. How do we know which one is which? The Undetectable Dragon Theory has far more unchecked assumptions (a...f) than the Empty Garage theory (everything in Undetectable Dragon, minus (a...f)).
Same thing for (forgive the extreme example) conspiracy theories. Moon landing hoaxers' ideas agree with observation— they just pile on a mountain of unchecked suppositions in order to avoid contradictions. If we're holding ourselves to good standards of belief, we pick the world model without all those extra unchecked assumptions. This becomes crucially important when there's disagreement about which theory is the Invisible Dragon theory.
Of course Copenhagen isn't nearly as bad as either of those, but the point is to call attention to the epistemological weight of each assumption we add, and what strategy we use for picking between two theories that are not (yet) contradicted by data. Copenhagen is doing more epistemological lifting, and so if we want to be good skeptics and efficient world model-builders, we should require its unchecked assumptions to be checked before we prefer it over other, more parsimonious theories which also agree with the data.
> which unfortunately adds much more personal preferences to the discussion
I quite disagree. The question is of "which strategy to use for picking models of reality which are most likely to be right". There are objectively good and bad strategies for doing that, in the same way that there are good and bad strategies for designing an airplane, or winning at chess, or proving a theorem. Of course no strategy guarantees success, and a "good" strategy might occasionally perform worse than a "bad" one— But without advance access to the solution, we don't know what those exceptions are, so our best bet is to go with the strategy which performs best a priori. In this case, for the sake of avoiding accidental belief in Dragons, the number of unchecked assumptions is centrally important!
[1] https://en.wikipedia.org/wiki/The_Demon-Haunted_World#Dragon...
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> "Everything is really under control of invisible stuff" make it impossible to use parisomy under any circumstances. It fundamentally discards Occam's Razor. You are fundamentally misunderstanding Occam's Razor. It is not a law - Occam's Razor is a preference for how to view the world, not a law that was violated. [1] There are alternate rules-of-thumb, such as one by Ockham's contemporary, Walter Chatton. Chatton c…
You are fundamentally misunderstanding Occam's Razor. It is not a law - Occam's Razor is a preference for how to view the world, not a law that was violated. Yes, Occam's Razor isn't a law but a method of understanding reality. My point is that if you throw out Occam's Razor in total, not in one or another situations, you're left with nothing to understand the world with. The "God wants it that ways" and "because it'…
Same thing if someone engineers a super complicated method to murder someone while appearing to physically be at a different place. It isn't the simplest explanation, but it can still be correct!
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The only difference in quantum physics is that there are actually two parallel universes: One in which you took out the red marble & one in which you took the blue one. You don't know what universe you're in until you look at the marble, but still it doesn't help you to transmit a message to your friend. I don't think it is helpful to talk about multiple universes, that makes a strong implication towards a many world…
> that makes a strong implication towards a many world interpretation You say that like it's a shortcoming. :) There are many who take the (very reasonable) position that the many worlds interpretation is the most epistemologically parsimonious one. Contrary to some misunderstandings of it, it doesn't "add" extra worlds; it removes the concept of "wave function collapse", and leaves all the other known laws of quantu…
1. It doesn't have anything to do with the topic at hand. It is, at best, a distraction. 2. It is impossible to design an experiment which is capable of distinguishing between a universe where many worlds is the correct interpretation of quantum mechanics or a universe where Copenhagen is the correct interpretation. Arguing about Copenhagen vs many worlds is literally no different than arguing about Jesus vs Mohamed. We simply do not have the tools to arrive at the truth of the matter. 3. You guarantee that everybody is going to stop discussing entanglement+FTL communication and will start arguing about interpretations of quantum mechanics. I'm not sure if anyone's started talking about De Broglie–Bohm theory yet, but it'll... oops I just did.
I say this as someone for whom many worlds feels truthier.
Couldn't that 'hidden variable' be just another dimension? So while those particles might have been separated in space by a large distance, on that fifth dimension they haven't moved and are still sitting side by side.
there are many ways to explain the result and all are extremely strange. particles communicating at FTL speeds? particles actually touching in an unknown dimension?
Couldn't that 'hidden variable' be just another dimension? So while those particles might have been separated in space by a large distance, on that fifth dimension they haven't moved and are still sitting side by side.
Earlier quoted context omitted.
>we have no idea where it is. It is probably encoded in the cosmic horizon a la Green's Theorem.
You're giving "probably" quite a workout there. For it to be encoded at the cosmic horizon, it has to communicate with the cosmic horizon. It's hard to see it doing so, within the time frame of the experiments, without superluminal communication.