Scott Aaronson (interviewed):
… after all the forbidding-sounding verbiage you read in popular books, quantum mechanics is astonishingly simple — once you take the physics out of it! In fact, QM isn’t even “physics” in the usual sense: it’s more like an operating system that the rest of physics runs on as application software. It’s a certain generalization of the laws of probability. It says nothing directly about electrons, photons, or anything like that. It just talks about lists of complex numbers called amplitudes: how these amplitudes change as a physical system evolves, and how to convert them into the probability of seeing this or that result when you measure the system. And everything you’ve ever heard about the “weirdness of the quantum world,” is simply different logical consequences of this one change to the rules of probability. This makes QM, as a subject, possibly more computer-science friendly than any other part of physics. In fact, even if our universe hadn’t been described by QM, I suspect theoretical computer scientists would’ve eventually needed to invent quantum computing anyway, just for internal mathematical reasons.