I liked the discussion, especially the final part on the many world interpretation (MWI).

I had the impression that Eliezer had a better understanding of quantum mechanics (QM), however I found one of his remarks very misleading (and it also confused Scott rightly): Eliezer seemed to argue that MWI somehow resolves the difficulty of unifying QM with general relativity (GR) by resolving non-locality.

It is true that non-locality is resolved by Everett's interpretation, but the real problem with QM+GR is that the renormalization of the gravity wave function does not seem to work out mathematically. At least not in a straightforward manner. However MWI requires gravity to be quantized and therefore forced the physicists to come up with a more elaborate solution.

Anyways, I agree with Eliezer on the other arguments in favor of MWI (linearity, locality, objectivity, etc...), but think that making overreaching remarks rendered his position at least a bit suspect for no good reason.

To be fair: MWI has its own technical quirks (e.g. choice of basis, explanation of probabilities,...) but they don't seem to be as fundamental as those of the classical interpretation. However the discussion would have been more interesting if Scott could have brought up those points rather than the purely philosophical issues.