Wednesday, June 6, 2018

Maudlin attacks positivism in book review

Philosopher of Physics Tim Maudlin writes in a book review, which is really just an excuse to write a nice essay on his favorite topics:
Logical positivism is a very attractive view for people who do not want to worry about what they cannot observe. It is ultimately a theory about meaning, about the content of a theory. According to the positivists, a theory says no more than its observable consequences.

Logical positivism has been killed many times over by philosophers. But no matter how many stakes are driven through its heart, it arises unbidden in the minds of scientists. For if the content of a theory goes beyond what you can observe, then you can never, in principle, be sure that any theory is right. And that means there can be interminable arguments about which theory is right that cannot be settled by observation. ...

Einstein was the great anti-positivist. His position is often called realism, but a better name is perhaps common sense. ...

So Einstein and Bohr were polar opposites in their approach to physics. Einstein demanded a clear and comprehensible account of what is going on in the physical world — at all scales — in space and time. Bohr thought that the key to quantum mechanics was the realization that no such thing could be had.

When the Copenhagen interpretation got imported to the pragmatic soil of the United States, Bohr’s incomprehensible nonsense was replaced by the more concise “shut up and calculate.” That is the philosophy that dominates physics to this day.
Maudlin is partial to interpretations of quantum mechanics that try to theorize about things that cannot be observed.

He is right that philosophers have done everything they can to kill logical positivism, but their arguments are unconvincing to many scientists. Einstein's anti-positivism has been a gigantic failure. Nothing good has come out of it.

On the other hand, all the great Physics triumphs of the XX century have been explicitly or implicitly positivist.

Einstein's early work was considered to be implicitly positivist. Many physicists praise him for what appeared to be positivist thinking. But he repudiated positivism in later life, and pursued unified field theories and attacked quantum mechanics.

"Realism" is a poor name for anti-positivism. The observations are what is real. Speculating about what cannot be seen is not.

The quantum (anti-positivist) realist seeks to find some intuitive simplistic mathematical model of the atom, like the Bohr atom of the old quantum theory. That might be nice, but there is good reason to believe that no such thing exists. The electron is not really a particle or a wave or anything else similar to any macroscopic object. The faulty models of the non-standard quantum interpretations have not been helpful.

As the great physicist Murray Gell-Mann said, after conversations with Putnam, “Bohr brainwashed a generation of physicists.” A vivid illustration of Kuhn’s kinship to Bohr in this respect can be drawn from Morris: “What I hated most about Kuhn’s lectures was the combination of obscurantism and dogmatism. On one hand, he was extremely dogmatic. On the other, it was never really clear about what.” It is no stretch to apply this precise description to Bohr, and not much of one to apply it to The Critique of Pure Reason as well.
There is something very strange about accusing a positivist of being obscure and dogmatic. The positivist is just the opposite.

The positivist talks about what is measurable and demonstrable. His conclusions can all be shown by experiments and logic. He remains silent on matters that cannot be empirically or logically decided.

I agree that Kuhn and later philosophers were obscure and dogmatic. Kuhn claimed to have some grand theory about how science works, but none of it makes any sense on closer inspection. He was mainly famous for his "paradigm shift" book, but no one can agree on what a paradigm shift is.
The difference between indicative propositions about the actual world and counterfactual propositions about mere possibilities is illustrated by these two conditionals: if Lee Harvey Oswald did not shoot John F. Kennedy, then someone else did (indicative and true); and if Oswald had not shot Kennedy, then someone else would have (counterfactual and probably false).
I do think that this sort of confusion about counterfactuals is at the root of some of the gripe about quantum mechanics. If you ask questions like "if the photon went thru this slit, then where would it hit the screen?", then it is hard to see why there is a diffraction pattern on the screen.
Kuhn implicitly accepts the descriptive view. The meanings of theoretical terms such as “mass” are determined by the theories in which they are deployed. Mass as used by Newton means something different from mass as employed by Einstein because the theories they are embedded in are different. Therefore Newtonians cannot really communicate with Einsteinians, Ptolemaic astronomers cannot really communicate with Copernican astronomers, and so on. This is why, for Kuhn, scientific revolutions cannot be settled by rational means: the disputants necessarily speak different languages.

The descriptive view was demolished by Kripke and Putnam in a series of lectures and papers in the 1970s.
Yes, that is at the core of what is wrong with Kuhn. Kuhn deduces that science is an irrational process (or "arational", which is the term he prefers). Denying that science is rational is a direct attack on the whole idea that scientists seek truth.

LuMo writes about a tweet:
The Defeat of Reason: Philosopher Tim Maudlin rebuts the influential relativism of Bohr's interpretation of quantum mechanics and Kuhn's interpretation of science.
— Steven Pinker (@sapinker) June 3, 2018
Pinker has basically endorsed an embarrassing, supportive review by Tim Maudlin of the painful anti-quantum book by Adam Becker. It's no coincidence that the title of Maudlin's reason describes quantum mechanics (plus, less importantly, Kuhn's views about the evolution of science as a human enterprise) as a "defeat of reason".
Again, it is odd to conflate Bohr's positivism with Kuhn's arational anti-positivism. Arguing that quantum mechanics is somehow a defeat of reason is really wacky. Pinker should stick to his field, which is psychology and language.

1 comment:

  1. "The electron is not really a particle or a wave or anything else similar to any macroscopic object." Yeah, that would be the failure of physics in general to explain anything and not the failure of "anti-positivism." You are advocating a mysticism as obscurantist as non-standard QM. Logic has to do with the rules of thought but there are many ways to think, even about the same set of empirical observations. Many theories can be given for the same set of facts because we never actually observe the causal nexus of nature. Measurement can be totally biased, if you realize it assumes what is to be found and what is to be ignored. For instance, my eyes can't see infrared radiation, like a pit viper. It doesn't take someone of the 33rd degree to notice how silent science has been on the Fortean, no matter how much evidence is produced. Positivism is as circular as anti-positivism. Neither are intelligible positions but are make-work academic philosophies. Humans simple want understanding. A theory should certainly be testable but that ignores how we guess at a theory to test (many times through induction or intuition). There is no reason to be overly dogmatic about anything we don't understand, except that we demand theories actually make verifiable predictions.