Comments by "Lepi Doptera" (@lepidoptera9337) on "I stopped working on black hole information loss. Here’s why." video.

@baguettegott3409 That quantum mechanics doesn't lose information is only true if we prevent the use of measurement AND assume that the quantum mechanical ensemble is actually real. There is a type of theorist who is willing to throw out the definition of science (which needs measurement and acknowledges that ensembles are pure abstracts that don't exist) to simplify the math for them. That's how such nonsensical statements come to pass.
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It is only valid if GR is a correct theory (which it isn't). A better model for a quantum mechanical black hole is more like a two dimensional plane (or torus) that has string hair. Near the surface of the classical singularity plane those hairs would be highly distinguishable, but closer to the event horizon they get dampened. Or maybe one can imagine that most of these hairs never reach the event horizon. One that does can emit a little bit of energy in form of Hawking radiation, probably through tunneling. I might be wrong about that picture. That's just my own homebrew and I am not a theorist, so take with about five metric tons of salt.
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It's much, much worse than that. A finite program can calculate the digits of pi to an arbitrary number of digits. Does pi contain a finite amount of information or an infinite amount?
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@briancornish2076 I am simply talking about pi as a source of a sequence of symbols here. OK, so let's call that a numerical representation of pi, instead. Does it contain a finite or an infinite amount of information? There are people who want to define information as the length of the shortest possible algorithm that can reproduce the original sequence. On some level that is a very good operational definition, but as you can see it reduces the representations of pi to something of fairly trivial information content, while many less famous irrational numbers would be the kings of information infinity. Actually, make that "almost all irrational numbers", because the number of finite programs is countable.
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@briancornish2076 Information isn't about meaning. Meaning is not something that can be quantified rationally. A text in Latin has very little meaning today, even though we can read it completely. Why? Because we are lacking the context. We can simply not imagine how a person who has never seen a traffic light or a cell phone would have felt reading the same text.
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@briancornish2076 13-69-21. How many fingers am I holding up and what's the age of the captain of the vessel that passes the equator in exactly seven minutes and 19 seconds? :-)
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@briancornish2076 The simple fact is that sequences that have the most information content (by the definitions of both information theory and physics) have the least "meaning" in human terms because they are essentially random number. This is a very "unfortunate" property of "information" because it confuses the heck out of everybody (including physicists, I am afraid). I don't know what else to tell you (and the public in general). This stuff is counterintuitive and nobody has found a "good" measure that satisfies our emotional needs for "order". You can, by the way, find plenty of examples in the history of science where human need for "divine order" has turned out to be completely counterfactual. Examples of that are platonic bodies in the theory of matter, the harmony of the spheres in celestial mechanics and similar projections of "pleasing symmetries" onto natural phenomena. The reality is different. Nature has absolutely no problems with cacophony. She actually thrives on it.
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Hawking radiation already follows from the third law of thermodynamics that no object/system can have a temperature of exactly 0K. I don't think it's all that controversial that we should want to keep the third law. The Hawking radiation spectrum, OTOH, that's model dependent.
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As an experimentalist I noticed that there is a certain class of modern theorists who like to talk about information whenever they have absolutely nothing to say about energy, momentum, angular momentum and charges. ;-)
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We do know what it is. It's so much mass-energy in such a small volume that it encloses itself with an event horizon. For all practical purposes such a region of space is a nearly perfect absorber. The entire discussion that ensues is about the difference between "perfect" and "nearly perfect", which in practice is not measurable with a simple spectral emission method.
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@JonathanJollimore-w9v Science is the rational description of nature. If nature doesn't show us something, then science is not required to describe what it doesn't show us. This isn't religion. We do not care about things that are only in people's imagination. IF there should be discrepancies between gravitational wave signatures of merging black holes and measurements by LIGO, then we will have to modify the theory. I am not aware that such discrepancies have been found, yet. For all purposes of science a black hole is simply an event horizon and we have a full theory for that.
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Actually, a black hole can probably destroy leptons, in which case it destroys lepton number, which is very important physical information.
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That is actually a very good question. Why is the evaporation process not symmetric? On a fundamental level it's not symmetric because most of the evaporation is very, very close to thermal equilibrium, while the collapse process is extremely far from it. In practice it black hole with the mass of a couple of solar masses (which would be the necessary mass of a neutron star) is completely quiet. It has a luminosity of 1e-30W or something on that order. I can't think of any macroscopic systems that have such a low electromagnetic emission power. Maybe something like an extremely long lived nucleus gets close... if we average the energy flux out over the lifetime.
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