3 ms·

All the people who use thinks like the word "information" in this context are confusing thermodynamic, logical, probabilistic, (+ many others) and equivocating.

All the people who use thinks like the word "information" in this context are confusing thermodynamic, logical, probabilistic, (+ many others) and equivocating. "Information" is not a physical quantity, and there cant be a "volume" of it. Nor does this have anything to do with real numbers. It is impossible for there to be any system extended in space and time to "zoom infinitely" into a continuous range and hence record an infinite amount of information. No one claims this, and the formulation of physics (entirely on real numbers) does not require it. Rather to say, eg., space is continuous, is to say its unbroken. There is no physical quantity which is becoming infinite.

mikk14 3y ago
Some people would disagree with dismissing information as non physical. For instance: https://scottaaronson.blog/?p=3327 https://scottaaronson.blog/?p=3327 The argument there would be that stuffing an extra bit of information in an information saturated volume would make it collapse into a black hole.
- mjburgess 3y ago
  It's not entirely clear "Energy" is a physical property either. By physical I mean a causal property of a system which is a basic constituent of reality. For example in E = 1/2mv^2, a particle has kinetic energy in virtue of being matter in motion -- it is motion and matter which are basic. Energy is just a system of accounting which tracks motion in the aggregate over time (with kinetic/potential just being the future/past in the accounting) hence why energy conservation is just a temporal invarience. When making arguments about the physical properties reality has (eg., whether aspects are continuous) you need to be exceptionally clear what your terms mean, and terminology in physics isnt designed for this. There are no "information saturated volumes", this is a series of abstractions piled on top of each other. All the words in this area have quite complex formal definitions that are have quite difficult to unpack semantics, you cannot just go around saying "saturated volumes" -- it is this sort of language which breeds cranks, and pop sci does it with abandon. This entire discussion is a matter of several PhDs, and to be done only well by people with PhDs in the matter (philosophy of physics), or equivalent research. It's not possible to scrap fragaments of what compusci bloggers say and derive much that's likely to be actually correct.
  - pishpash 3y ago
    Nothing in physics is more basic than something else, as there are equivalent formulations in other quantities. Energy and momentum are as real as matter and motion. Matter is bundles of energy exhibiting inertia and motion is just some transformational relationship between phenomena in different areas of space-time. There is nothing "real" about any of this, only what animals like humans have evolved to model directly in their brains.
  - calf 3y ago
    Aaronson is one of the world's top quantum computing scientists, he's a professor at I believe UT Austin. He's also written papers that are basically philosophy of physics. It would be interesting to go over what he has actually said on this topic.
- mikhailfranco 3y ago
  Yes, the thermodynamic properties of information are well established. Various Hawking-Bekenstein results about black holes relate to information density, especially, shockingly, that information is proportional to surface area, not volume. This makes perfect sense because a black hole has all its incoming matter and energy sprawled, flattened and red-shifted on its horizon (to a distant observer). It can never export its internal state to the outside world, so you might never expect a volume's-worth of states to be exposed. The idea was generalized by 't Hooft to the Holographic Principle, for 2D screens encoding the state of 3D volumes on the other side. However, the full AdS/CFT Correspondence only applies to a certain type of AdS space, not our actual dS space. At the moment, it seems half of theoretical physics doctoral students are trying to extend AdS/CFT to dS space (obviously - strings :) and half of observational astrophysics doctoral students are desperately hoping to show we live in AdS space - LOL
n4r9 3y ago
I suspect that Gisin has a very clear idea of what he means by "information" in this context, having worked for over 40 years at the forefront of theoretical physics with a specialisation in quantum information theory.
- kergonath 3y ago
  I can link to people who’ve worked their whole life on various fields of Physics who still talk about perpetual motion. I am not saying he is wrong in this specific case, but an appeal to authority is not very convincing.
  - n4r9 3y ago
    I've given your comment quite a lot of thought over the last few days. Maybe too much. At first I was inclined to agree with you that this is an appeal to authority, with the caveat that such appeals do not always constitute a fallacy. For example, if we both agreed that such a Gisin is an expert whose opinion on this topic can be trusted, then his statements are valid evidence for one way or another. But then I realised that the very claim being challenged is whether Gisin knows what he's talking about. Floating his credentials and experience feels like a valid contribution. For what it's worth, back in my PhD days I read several of his papers and saw a couple of his talks at conferences, and can confirm he's one of the leading researchers in the field and is particularly thoughtful and careful in his work.
- mjburgess 3y ago
  I don't have much issue with Gisin's solution, the idea that the reals are random is one solution to the problem of how to deal with them that I like (since, my meta-issue is whether reality is computable, I say it isnt, and randomness is not computable). There's a problem for people who think reality can be modelled by computable functions of finite inputs: this makes classical physics non-deterministic, because chaos requires infinite precision for determinism. So either you go for "reality is deterministic and continuous, and not computable" or "reality is non-deterministic, and discrete, and not computable" either option in this fork includes properties that offend the minds of the people who want everything to be discrete. I lean towards a preference for determinism & continuity (via, in QM, superdeterminism) since that's trivial to justify on our best physics

mikk14 3y ago

Some people would disagree with dismissing information as non physical. For instance: https://scottaaronson.blog/?p=3327 https://scottaaronson.blog/?p=3327 The argument there would be that stuffing an extra bit of information in an information saturated volume would make it collapse into a black hole.

mjburgess 3y ago
It's not entirely clear "Energy" is a physical property either. By physical I mean a causal property of a system which is a basic constituent of reality. For example in E = 1/2mv^2, a particle has kinetic energy in virtue of being matter in motion -- it is motion and matter which are basic. Energy is just a system of accounting which tracks motion in the aggregate over time (with kinetic/potential just being the future/past in the accounting) hence why energy conservation is just a temporal invarience. When making arguments about the physical properties reality has (eg., whether aspects are continuous) you need to be exceptionally clear what your terms mean, and terminology in physics isnt designed for this. There are no "information saturated volumes", this is a series of abstractions piled on top of each other. All the words in this area have quite complex formal definitions that are have quite difficult to unpack semantics, you cannot just go around saying "saturated volumes" -- it is this sort of language which breeds cranks, and pop sci does it with abandon. This entire discussion is a matter of several PhDs, and to be done only well by people with PhDs in the matter (philosophy of physics), or equivalent research. It's not possible to scrap fragaments of what compusci bloggers say and derive much that's likely to be actually correct.
- pishpash 3y ago
  Nothing in physics is more basic than something else, as there are equivalent formulations in other quantities. Energy and momentum are as real as matter and motion. Matter is bundles of energy exhibiting inertia and motion is just some transformational relationship between phenomena in different areas of space-time. There is nothing "real" about any of this, only what animals like humans have evolved to model directly in their brains.
- calf 3y ago
  Aaronson is one of the world's top quantum computing scientists, he's a professor at I believe UT Austin. He's also written papers that are basically philosophy of physics. It would be interesting to go over what he has actually said on this topic.
mikhailfranco 3y ago
Yes, the thermodynamic properties of information are well established. Various Hawking-Bekenstein results about black holes relate to information density, especially, shockingly, that information is proportional to surface area, not volume. This makes perfect sense because a black hole has all its incoming matter and energy sprawled, flattened and red-shifted on its horizon (to a distant observer). It can never export its internal state to the outside world, so you might never expect a volume's-worth of states to be exposed. The idea was generalized by 't Hooft to the Holographic Principle, for 2D screens encoding the state of 3D volumes on the other side. However, the full AdS/CFT Correspondence only applies to a certain type of AdS space, not our actual dS space. At the moment, it seems half of theoretical physics doctoral students are trying to extend AdS/CFT to dS space (obviously - strings :) and half of observational astrophysics doctoral students are desperately hoping to show we live in AdS space - LOL

n4r9 3y ago

I suspect that Gisin has a very clear idea of what he means by "information" in this context, having worked for over 40 years at the forefront of theoretical physics with a specialisation in quantum information theory.

kergonath 3y ago
I can link to people who’ve worked their whole life on various fields of Physics who still talk about perpetual motion. I am not saying he is wrong in this specific case, but an appeal to authority is not very convincing.
- n4r9 3y ago
  I've given your comment quite a lot of thought over the last few days. Maybe too much. At first I was inclined to agree with you that this is an appeal to authority, with the caveat that such appeals do not always constitute a fallacy. For example, if we both agreed that such a Gisin is an expert whose opinion on this topic can be trusted, then his statements are valid evidence for one way or another. But then I realised that the very claim being challenged is whether Gisin knows what he's talking about. Floating his credentials and experience feels like a valid contribution. For what it's worth, back in my PhD days I read several of his papers and saw a couple of his talks at conferences, and can confirm he's one of the leading researchers in the field and is particularly thoughtful and careful in his work.
mjburgess 3y ago
I don't have much issue with Gisin's solution, the idea that the reals are random is one solution to the problem of how to deal with them that I like (since, my meta-issue is whether reality is computable, I say it isnt, and randomness is not computable). There's a problem for people who think reality can be modelled by computable functions of finite inputs: this makes classical physics non-deterministic, because chaos requires infinite precision for determinism. So either you go for "reality is deterministic and continuous, and not computable" or "reality is non-deterministic, and discrete, and not computable" either option in this fork includes properties that offend the minds of the people who want everything to be discrete. I lean towards a preference for determinism & continuity (via, in QM, superdeterminism) since that's trivial to justify on our best physics