Wednesday, July 2, 2014

Carroll goes nuts with many worlds

After defending bad science philosophy, physicist Sean M. Carroll foes off the deep end with his own bad quantum philosophy, and posts Why the Many-Worlds Formulation of Quantum Mechanics Is Probably Correct:
There are other silly objections to EQM, of course. The most popular is probably the complaint that it’s not falsifiable. That truly makes no sense. It’s trivial to falsify EQM — just do an experiment that violates the Schrödinger equation or the principle of superposition, which are the only things the theory assumes. Witness a dynamical collapse, or find a hidden variable. Of course we don’t see the other worlds directly, but — in case we haven’t yet driven home the point loudly enough — those other worlds are not added on to the theory. They come out automatically if you believe in quantum mechanics.
This is nonsense. I don't want to keep picking on Carroll, but it seems that more and more physicists are reciting such nonsense in favor of MWI. (Carroll also calls it Everettian quantum mechanics, EQM.)

Lumo explains how Carroll is wrong
At the same time, salesmen like Carroll offer you lots of incredible statements such as the statement that this "many worlds interpretation" directly follows from quantum mechanics, is directly justified by quantum mechanics (more justifiable in quantum mechanics than in classical physics), and unlike proper quantum mechanics, it doesn't introduce any new physical laws. All these statements are untrue. They are really the polar opposite of the truth.

First, many worlds surely don't follow from quantum mechanics.

Quantum mechanics is the universal framework of modern physics which is a natural science. As every natural science, physics predicts or explains the observations that are actually being made in one Universe.
The 2013 paper, On Quantum Theory, by Berthold-Georg Englert also explains:
Quantum theory had essentially taken its final shape by the end of the 1920s and, in the more than eighty years since then, has been spectacularly successful and reliable — there is no experimental fact, not a single one, that contradicts a quantum-theoretical prediction. Yet, there is a steady stream of publications that are motivated by alleged fundamental problems: We are told that quantum theory is ill-defined, that its interpretation is unclear, that it is nonlocal, that there is an unresolved “measurement problem,” and so forth.

It may, therefore, be worth reviewing what quantum theory is and what it is about.
That is correct. Quantum mechanics, as it has been described in textbooks for decades, is a perfectly good theory. It is strikingly successful, and yet from Einstein in the 1930s to many well-known physicists today, they act as if the theory is broken. They even say that realizing that quantum mechanics requires many worlds is like the Copernican revolution.

This modern rejection of quantum mechanics is just as crazy as if modern physicists went around claiming that particles can go faster than light because they don't believe relativity. I wonder how they ever passed their PhD qualifying exams without understanding quantum mechanics.

Carroll is proof that a physicist can lose the capacity for scientific thinking if his brain is infected with lousy philosophy.

The principle reason for rejecting MWI is that it postulates an infinity of unobservable worlds without any physical benefit. It adds no practical or conceptual advantages over textbook quantum mechanics, and is unscientific in having supernatural beliefs. It even has disadvantages, because it makes probabilities nearly impossible to interpret. Its advocates claim that it cures some philosophical defect of quantum mechanics, but there is no such defect.

The quantum computing folks, like David Deutsch, love MWI because the extra universes are supposedly where the super-Turing computation takes place. No such computation has ever been observed, and the whole field is a big funding scam.


  1. "[Quantum theory is] spectacularly successful and reliable"

    And its completely useless in the real world of chemistry. Quantum chemistry cannot even predict crystal structures of organic compounds. Nobody understands the pile of approximations, its a big mess of computer codes. At least the motivation for a "bigger" computer is warranted. Hey Lubos, let me know when your string theory crap is good for making a better battery.

  2. "whole field is a big funding scam"

    Well, I guess you haven't looked at Berthold-Georg Englert's publication list that is mainly on quantum information processing the past few years. Or that he is the Principal Investigator at the Centre for Quantum Technologies whose mission is:

    "Our mission is to conduct interdisciplinary theoretical and experimental research in quantum theory and its application to information technologies. The discovery that quantum physics allows fundamentally new modes of information processing has required that classical theories of computation, information and cryptography be superseded by their quantum generalizations. These hold out the promise of faster computation and more secure communication than is possible classically."

    So, what gives, Roger? Both Motl and Englert, your voices of sanity on quantum mechanics, are either actively working in a field (quantum computing) that "is a big funding scam" or endorse its legitimacy. So you are arguing that they are sane once in a while?

  3. I would argue that what makes one right or wrong, correct or incorrect is not your name, your position, or your pedagree. It is possible sometimes for even a child to take note that "The emperor has no clothes on", when everyone else is missing the obvious for various reasons. I also understand that broken clocks are correct twice a day.

  4. How about putting the QM posts in a logical order? I'd like to go through them in some logical sequence.

  5. I suggest that you read my posts on counterfactuals. Click on the link, and read in chronological order, starting with the introduction.