Rationalist check-list:
- Incorrect use of analogy? Check.
- Pseudoscientific nonsense used to make your point seem more profound? Check.
- Tortured use of probability estimates? Check.
- Over-long description of a point that could just have easily been made in 1 sentence? Check.
This email by SBF is basically one big malapropism.
That blog post irritates me in multiple directions every time I am reminded of it. The wrongness is so layered that any response I attempt degenerates into do you even Bloch sphere, bro before I give up and find something more worthwhile to do with my life.
Yud loves to go on about how the map is not the territory, to the extent that his cult followers think he coined the phrase, but he is remarkably terrible at understanding which is which. Or, to be a little more precise, he is actively uninterested in appreciating that the question of what to file under “map” versus “territory” is one of the big questions that separate the different interpretations of quantum mechanics. He has his desired answer, and he argues for it by assertion.
He’s also just ignorant about the math. Stepping back from the details of what he gets wrong, there are bigger-picture problems. For example, he points to a complex number and says that it can’t be a probability because it’s complex. True, but so what? The Fourier transform of a sequence of real numbers will generally have complex values. Just because one way of expressing information uses complex numbers doesn’t mean that every perspective on the problem has to. And, in fact, what he tries to do with two complex numbers — one amplitude for each path in an interferometer — you can actually do with three real numbers. They can even be probabilities, say, the probability of getting the “yes” outcome in each of three yes/no measurements. The quantumness comes in when you consider how the probabilities assigned to the outcomes of different experiments all fit together. If probabilities are, as Yud wants, always part of the “map”, and a wavefunction is mathematically equivalent to a set of probabilities satisfying some constraint, then a wavefunction belongs in the “map”, too. You can of course argue that some probabilities are “territory”; that’s an argument which smart people have been having back and forth for decades. But that’s not what Yud does. Instead, through a flavor swirl of malice and incompetence, he ends up being too much a hypocrite to “steelman” the many other narratives about quantum mechanics.