By "collapse theory" I presume you mean the Copenhagen interpretation of Quantum Mechanics? That actually gives the guy more credibility: it suggests he learned physics at a physics department of some university, as opposed to, say, from popular literature or random blogs.

The page you linked says: "the many-worlds interpretations wins outright given the current state of evidence". This sentence does not make sense. The MWI, just like the Copenhagen interpretation and all other interpretations of Quantum Mechanics, are just this: interpretations. They don't disagree about the expected outcome of any imaginable measurement. They can't be tested experimentally. Choosing one interpretation or the other is a philosophical choice, not a scientific conclusion. "Evidence" in favor of one interpretation of Quantum Mechanics is of the same kind as "evidence" of the existence (or non-existence) of God, i.e., some people feel very strongly one way or another and will argue with you to death about it, not to mention create web pages which authoritatively state their opinions on the subject, but the disagreement cannot really be resolved by arguments or by empiric observations.

Physicists are aware of this and that's why most of them choose the simplest thing and talk about the collapse of the wave function.

I'm not going to go into the arguments about it, I've given you the link so you can read them all yourself. Though I will quote two big things (edited for note: assertions, not arguments for them; arguments are at the link above) against collapse postulates in general, since you probably didn't read them and perhaps you have a response why it doesn't matter:

"If collapse actually worked the way its adherents say it does, it would be the only non-linear evolution in all of quantum mechanics, the only non-unitary evolution in all of quantum mechanics, the only non-differentiable (in fact, discontinuous) phenomenon in all of quantum mechanics, the only phenomenon in all of quantum mechanics that is non-local in the configuration space, the only phenomenon in all of physics that violates CPT symmetry, the only phenomenon in all of physics that violates Liouville's Theorem (has a many-to-one mapping from initial conditions to outcomes), the only phenomenon in all of physics that is acausal / non-deterministic / inherently random, and the only phenomenon in all of physics that is non-local in spacetime and propagates an influence faster than light."

Second, now paraphrasing, is that many-worlds, aka macroscopic decoherence (QM applied universally), is a strictly simpler theory and Occam's Razor alone rules out collapse as it's an added detail not needed.

Lastly, this is just my own opinion, but just because you learned from a set of standard textbooks or from a physics department at some place, doesn't necessarily mean you learned correctly. Truth isn't what the university teaches, even though there's a lot of overlapping. (I have learned there are apparently still some people teaching that we are evolved from chimps.)

Check out Dirac's classic 'The Principles of Quantum Mechanics':

http://www.amazon.com/Principles-Quantum-Mechanics-Internati...

I was shocked how much clearer (and more useful) the exposition is compared to textbooks.

I strongly second this recommendation, but it's not exactly "light on math". It's light on calculations, but you need to have had some contact at the very least with linear algebra and calculus. Now that I think about it, that probably makes it a perfect book for software engineers, who know the mathematical concepts from studying computer science, but have not much experience actually doing calculations, so typical QM textbooks may be off-putting for them.

Thanks! Added to my wish list, I'll have to see if it's at my library. I'm all for finding textbooks that are actually well-written.

Is there really reason to believe that practicing theoretical physicists who advocate wavefunction collapse are so mistaken as to be not worth learning from? I find the lesswrong cultural insistence on going with MWI pretty troubling when it gets to the point of not listening to actual physicists who don't use it, as as far as I can tell, very few people there are actual active quantum physics researchers.

MWI could well be a better way to develop understanding of quantum mechanics, but dissing people who actually actively work with the stuff because their established notation has historical baggage doesn't seem like a good idea when you're not actively working with the stuff yourself.

I believe they are very mistaken, just like I believe practicing scientists who also believe in God are very mistaken. There are arguments for and against my beliefs, and I don't want to go into them here. I'm just explaining that to me a spiritual scientist (or a collapse-postulate scientist) is placed in a category where I can't believe that they take their science all that seriously. This doesn't make them impossible to learn from, or not worth it, or wrong about everything, but honestly I'd rather learn from someone more serious and excited about learning like Feynman. Someone who revels in the odd and beautiful nature of reality and doesn't need to invent comfortable intuition-friendly (and complicated) "reasons" why or how something does something.

That said, if such scientists that I put into my would-rather-not-learn-from category want to teach me some math or programming or something solid and backed by experiment, if they want to show me an experiment to learn from, I'm all for it! I grew up in Utah, I can't think of a single influential teacher not a Mormon, obviously I didn't think because they were religious they weren't worth learning from.