Information theory presupposes the notion of an epistemic agent, such as a scientist or an idealized human. Despite that, information theory is increasingly invoked by physicists concerned with fundamental physics, physics at very high energies, or generally with the physics of situations in which even idealized epistemic agents cannot exist. ...It is funny how these physicists talk about information as if it is something real, and then talk about what it has to be inside a black hole, where there is no possibility of any observation.
Physicists working in quantum gravity diverge rather radically over the physical principles that they take as their starting point in articulating a quantum theory of gravity, over which direction to take from these points of departure, over what we should reasonably take as the goals of the enterprise and the criteria of success, and sometimes even over the legitimacy of different methods of evaluation and confirmation of the resulting theories. Yet, there is something that most of them agree upon: that black holes are thermodynamical objects, have entropy and radiate, and thus that the Bekenstein-Hawking formula for the entropy of a black hole must be recovered, more or less directly, from the microphysics of the fundamental degrees of freedom postulated and described by their theories.1 Yet none of this has ever been empirically confirmed.
Furthermore, this seems to be a core postulate of quantum gravity. The quantum gravity theorists think that they can be the new Einstein, adopt some silly postulates like this, and deduce what is going on at the center of a black hole.
Meanwhile, a new YouTube video on Why Black Holes Could Delete The Universe – The Information Paradox already has about 3 million views. That is very rapid growth for a physics video. This is as viral as it ever gets for quantum mechanics.
The slick video says:
According to the theory of quantum mechanics, information is indestructible. It might change shape, but it can never be lost.The video goes on to describe black holes, and discuss whether information gets lost in black holes.
For example, if you burn a piece of paper, you get ash. That ash will never become paper again. But, if you were able to carefully collect every single carbon atom in the ash, and measure the exact properties of the smoke and heat radiating from the fire, you could, in theory, reconstruct the paper. The information of the paper is still in the universe. It is not lost, it is just hard to read.
No the theory of quantum mechanics does not say that information is indestructible. The common textbooks do not say it. Bohr, Heisenberg, Schrodinger, Dirac, and Feynman never said it. Nobody got a Nobel Prize for it. No experiment ever confirmed it.
Instead, we have some goofy physics popularizers who do not believe in time, or believe that time is reversible, or who deny that the past causes the future, or believe in many-world interpretation, or other such nonsense. They notice that if you reverse time in the Schrodinger equation, and take the complex conjugate, then you get the same equation. That has been obvious for 90 years.
It is also obvious that when you burn a piece of paper, the info on it is lost.
And the application to black holes is just more nuttiness, as no one knows what is inside a black hole.
Update: Here is another new article on how everything is information:
Wheeler said the universe had three parts: First, “Everything is Particles,” second, “Everything is Fields,” and third, “Everything is information.” In the 1980s, he began exploring possible connections between information theory and quantum mechanics. It was during this period he coined the phrase “It from bit.” The idea is that the universe emanates from the information inherent within it. Each it or particle is a bit. It from bit. ...At least the article admits, buried in the silliness, that this is a fringe theory that no one can test.
It’s important to note that most physicists believe that matter is the essential unit of the universe. And information theory’s proof is limited. After all, how would you test for it?
If the nature of reality is in fact reducible to information itself, that implies a conscious mind on the receiving end, to interpret and comprehend it. Wheeler himself believed in a participatory universe, where consciousness holds a central role. Some scientists argue that the cosmos seems to have specific properties which allow it to create and sustain life. Perhaps what it desires most is an audience captivated in awe as it whirls in prodigious splendor.
Modern physics has hit a wall in a number of areas. Some proponents of information theory believe embracing it may help us to say, sew up the rift between general relativity and quantum mechanics. Or perhaps it’ll aid in detecting and comprehending dark matter and dark energy, which combined are thought to make up 95% of the known universe. As it stands, we have no idea what they are. Ironically, some hard data is required in order to elevate information theory. Until then, it remains theoretical.