Sabine Hossenfelder, AdS/CFT, and demagogy

Under Sabine Hossenfelder's article that contained a link to Jan de Boer's talk about holography, a reader nicknamed Gilesgoatboy recalled the 2008 Hossenfelder's discussion concerned with the black hole information loss paradox.



She has dismissed the stringy and holographic solution to the problem by the following two strange paragraphs:

Solution: Since the AdS/CFT conjecture relates black holes (in AdS space) to a quantum theory one knows is unitary on the boundary, this would mean the evolution in the bulk is also unitary.

Problem: As long as the conjecture is unproved one could equally well consider the information loss problem, if real, as a counter-example for the validity of the conjecture. (Also, I personally would find it unsatisfactory would this only work in AdS space).

Gilesgoatboy correctly mentions that Hossenfelder is right in claiming that the contrapositive (non Q implies non P) is equivalent to the original statement (P implies Q) but this logical tautology doesn't contain any nontrivial scientific evidence that actually changes the probabilities that either P or Q is valid: it has no beef.

Moreover, if she were impartial, she would realize (and acknowledge) that her "argument" may be shot against any potential "solution" of the paradox, not just against the AdS/CFT that she chose: any solution has to reject either locality or unitarity, so there would always exist a Hossenfelder-level of a "counter-argument" against this solution. The very fact that it is a solution is what Hossenfelder doesn't like.




So her tautological observation is actually not a "problem" of the "solution" in any sense: the descriptions of the second paragraph is wrong. Needless to say, Hossenfelder denies that Gilesgoatboy has demonstrated that she has nothing to say about the physics. She only picks the reader's agreement with her tautology and "closes the discussion" before she could learn why this tautology has no impact on the science.

She must know that what she's doing is simply a dishonest, unscientific, demagogic, cherry-picked, censored, authoritarian distortion of the facts and fabrication of nonsensical propaganda. But she doesn't care. The system has allowed similar people to get into it, much like it has allowed Amy Bishop to hide the likely murder of her brother 24 years ago (it's so politically incorrect to say that a woman is a complete fraud, isn't it?), so she will continue with this unethical stuff at any cost.

Just to demonstrate what is a scientific argument and what is not, let's consider the following analogy of the information loss paradox. It's the following "paradox" of the evolutionary biology:

Original problem: It takes a lot of time for complex life forms to evolve. But because the Earth is just 6,000 years old, there hasn't been enough time for the evolution to take place.

Imagine that some people suddenly found evidence that the lifetime of the Earth wasn't that short (the information is not lost). There are many reasons to know it's the case, but let's choose an example:

Solution: The Earth is actually not that young because the layers of ice in the Vostok ice core are related to annual cycles in the past. They show that the ice has accumulated at least for 650,000 years, so the Earth is surely older than 6,000 years.

Does it solve the original "paradox" of Darwin's theory? Well, it doesn't, according to Sabine ID Hossenfelder:

Problem with the solution: As long as the conjecture about those 650,000 annual layers of ice in the Vostok ice core is unproved, one could equally well consider the Young Earth, if real, as a counter-example for the annual interpretation of the Vostok ice core layers. (Also, I personally would find it unsatisfactory would this only work in the Antarctica.)

Now, this is a delicate mixed bag. Indeed, it's true that if the Earth were young, the layers of ice in the Antarctica couldn't correspond to individual years because there are way too many of them. ;-) But does it actually make the Vostok ice core less valid a source of historical data than it was before the argument?

Clearly, it doesn't. This relationship between the two logical propositions was just a tautology - and the tautologies have always been obvious to all people who can rationally think. There's nothing else in the argument, so the probability of both statements - the Earth is old and the Vostok ice core recorded the history year-by-year - remained unchanged.

On the other hand, the discovery of the Vostok ice core was nontrivial and it did change our estimated probabilities that the Earth is ancient because of the logical relationship. But what has actually driven the change is not the logical relationship itself - which is kind of obvious. The change was totally driven by the actual discovery of the layers in the Vostok ice core.

The very same thing is true in the AdS/CFT case and the information loss paradox. The logical relationship between the two has always been obvious: if one could show that the information was actually preserved in a quantum system involving gravity, the paradox couldn't hold. Gravity can manage to co-exist with quantum mechanics. That's exactly what has happened.

But all the nontrivial events that actually changed the odds that the information was preserved during the black hole evaporation occurred in the context of the research into string theory (and its applications). The logical implication is just a tautology and while it's important, it's completely trivial and old.

The beef is the amazing AdS/CFT research that has shown that the CFT - a manifestly unitary theory on the boundary - actually contains gravitons with the right scattering amplitudes, massless and excited strings, wrapped and unwrapped branes, and whole phase diagrams of systems as complex as rotating black holes that are identified with analogous diagrams for superconductors or a heavy ion soup in the CFT. Only unreasonable people think that the AdS/CFT correspondence is seriously invalid, even in some common physical situations.

Also, it's completely irrational - and logically unjustifiable - for Ms Hossenfelder to claim a "disappointment" that the solution would only work in the Antarctica or the AdS space (think about both examples at the same moment, please). The fact that the first evidence was found in Antarctica doesn't make it less valid. There are no "quotas" that would imply that the evidence supporting an ancient Earth has to be found uniformly over the whole globe or the whole Universe.

In fact, the evidence from the Antarctica is enough to show that the Earth is older than 6,000 years. And there are other pieces of evidence from other places. In the very same way, the AdS/CFT correspondence - which preserves the information in the AdS space - is enough to show that black holes - even astrophysically large black holes in asymptotically (nearly) flat space - do preserve the information. For technical reasons, such evidence is easier to be obtained in the Antarctica - or in the anti de Sitter space. (It can also be obtained for some flat spaces described by Matrix theory which is equally unitary.) But there's no disadvantage connected with such a "localization" of the evidence. On the contrary, it's an advantage for a scientist to be able to look for the evidence in the right place - where the evidence can actually be found so that some old questions can be (almost) settled - instead of preserving the (uncertain) status quo that was created by a more robust but still insufficient evidence from the past. Assuming that he was not just (mostly) lucky, Juan Maldacena has surely shown lots of this talent. ;-)

It follows that the arguments leading to the Young Earth - or to the opinion that the information has to be lost - must be wrong. Of course, we qualitatively know "why": the Bible can't be literally trusted as a source of geological and cosmological data - and the locality doesn't strictly hold in finite regions of spacetime because the information may "tunnel" from one place to another, and get out of the black hole. Once these old assumptions that used to lead to the paradoxes are shown to be wrong, they're wrong in other environments, too. The Earth is ancient not only in the Antarctica and the information is preserved by the black holes not only in anti de Sitter spaces. The paradoxes have disappeared.

Of course, there's still some (extremely remote) possibility that the AdS/CFT (and Matrix theory) descriptions of quantum gravity are wrong, in some sense that remains elusive, and that all the positive evidence is just an illusion. And there's some chance that the Earth is just 6,000 years old and it just seems to be older. And the 650,000 layers can be just daily layers (from 1780 years) because the climatologists are that dumb. ;-)

But this "negative evidence" simply doesn't exist today (except for the Holy Scripture that has been understood to be less reliable than the huge body of the empirical evidence). And there exist 5,000 papers which happened to have led to diverse positive evidence that seem to imply that the manifestly unitary CFT is doing everything that a theory of quantum gravity should be doing, including the right behavior of the evaporating black holes.

So the comparison of the evidence shows that there is almost certainly no problem. It is breathtakingly dishonest for Ms Hossenfelder to pretend that her "problem" with the solution which just states her desire for the problem to persist - and her belief that the results in string theory don't show that the information is preserved - remains on par with the proposition that the information is preserved, as seen from the results of the AdS/CFT research (and others).

There is no equivalence between the two attitudes, much like there is no equivalence between gold and shit. And be sure that Ms Hossenfelder is not the former.

People like Ms Hossenfelder love to preserve the "problems" (global warming "problems" are just other examples) despite all the evidence. They love to deny the evidence and to cherry-pick the data (and even the opinions and insights of others) in order to support predetermined conclusions. They think that just by stating - or repeating - some almost certainly untrue (according to the available evidence) propositions about "persisting problems", they're making them equally justified as the "problem non-existence" arguments which are supported by tons of evidence.

Why are they doing it? Well, because it's so convenient. It helps them to mask that what they have been saying and writing throughout their lives has been crap. They don't have to make any real work that makes any sense and they preserve the perceived value of the crap; it has worked for them so far. And Sabine Hossenfelder in particular has always gotten away with such dishonest tricks because it's politically correct to give a free pass to all women in physics. The case of Amy Bishop should be viewed as another warning against the deadly power of political correctness. People like Hossenfelder have no business to be in science and it's extremely worrisome if some people around her are trying to hide this fact.

And that's the memo.