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OrphanWilde comments on Welcome to Less Wrong! (5th thread, March 2013) - Less Wrong
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QM Sequence is two parts:
(1) QM for beginners
(2) Philosophy-of-science on believing things when evidence is equipoise (or absent) - pick the simpler hypothesis.
I got part (1) from reading Dancing Wu-Li Masters, but I can clearly see the value to readers without that background. But teaching foundational science is separate from teaching Bayesian rationalism.
The philosophy of the second part is incredibly controversial. Much more than you acknowledge in the essays, or acknowledge now. Treating the other side of any unresolved philosophical controversy as if it is stupid, not merely wrong, is excessive and unjustified.
In short, the QM sequence would seriously benefit from the sort of philosophical background stuff that is included in your more recent essays. Including some more technical discussion of the opposing position.
If you learned quantum mechanics from that book, you may have seriously mislearned it. It's actually pretty decent describing everything up to but excluding quantum physics. When it comes to QM, however, the author sacrifices useful understanding in favor of mysticism.
Hrm? On a conceptual level, is there more to QM than the Uncertainty Principle and Wave-Particle Duality? DWLM mentions the competing interpretations, but choosing an interpretation is not strictly necessary to understand QM predictions.
For clarity, I consider the double-slit experimental results to be an expression of wave-particle duality.
I will admit that DWLM does a poor job of preventing billiard-ball QM theory ("Of course you can't tell momentum and velocity at the same time. The only way to check is to hit the particle with a proton, and that's going to change the results.").
That's a wrong understanding, but a less wrong understanding than "It's classical physics all the way down."
Yes. Very yes. There are several different ways to get at that next conceptual level (matrix mechanics, the behavior of the Schrödinger equation, configuration spaces, Hamiltonian and Lagrangian mechanics, to name ones that I know at least a little about), but qualitative descriptions of the Uncertainty Principle, Schrödinger's Cat, Wave-Particle Duality, and the Measurement Problem do not get you to that level.
Rejoice—the reality of quantum mechanics is way more awesome than you think it is, and you can find out about it!
Let me rephrase: I'm sure there is more to cutting edge QM than that which I understand (or even have heard of). Is any of that necessary to engage with the philosophy-of-science questions raised by the end of the Sequence, such as Science Doesn't Trust Your Rationality?
From a writing point of view, some scientific controversy needed to be introduced to motivate the later discussion - and Eliezer choose QM. As examples go, it has advantages:
(1) QM is cutting edge - you can't just go to Wikipedia to figure out who won. EY could have written a Lamarckian / Darwinian evolution sequence with similar concluding essays, but indisputably knowing who was right would slant how the philosophy-of-science point would be interpreted.
(2) A non-expert should recognize that their intuitions are hopelessly misleading when dealing with QM, opening them to serious consideration of the new-to-them philosophy-of-science position EY articulates.
But let's not confuse the benefits of the motivating example with arguing that there is philosophy-of-science benefit in writing an understandable description of QM.
In other words, if the essays in the sequence after and including The Failures of Eld Science were omitted from the Sequence, it wouldn't belong on LessWrong.
A deeper, more natural way to express both is "wavefunction reality," which also incorporates some of the more exotic effects that come from using complex numbers. (The Uncertainty Principle also should be called the "uncertainty consequence," since it's a simple derivation from how the position and momentum operators work on wavefunctions.)
(I haven't read DWLM, so I can't comment on its quality.)