Reality and the Tooth Fairy

Max Tegmark writes in the current SciAm magazine, defending the multiverse:

1) Omnivision assumption: physical reality must be such that at least one observer can in principle observe all of it.

2) Pedagogical reality assumption: physical reality must be such that all reasonably informed human observers feel they intuitively understand it. ...

(1) and (2) appear to be motivated by little more than human hubris. The omnivision assumption effectively redefines the word "exists'' to be synonymous with what is observable to us humans, akin to an ostrich with its head in the sand. Those who insist on the pedagogical reality assumption will typically have rejected comfortingly familiar childhood notions like Santa Claus, local realism, the Tooth Fairy, and creationism — but have they really worked hard enough to free themselves from comfortingly familiar notions that are more deeply rooted? In my personal opinion, our job as scientists is to try to figure out how the world works, not to tell it how to work based on our philosophical preconceptions.

It is strange to compare local realism with the Tooth Fairy. Local realism is one of those bedrock principles of physics like conservation of energy that has directly inspired numerous scientific breakthrus and has never been contradicted by experiment. Yes, I know that there are some obscure interpretations of quantum mechanics that deny local reality, but those are fringe beliefs. I say that Tegmark is the one who is disconnected from reality.

Local reality is not a childish notion. It is more intuitively understandable than the alternatives. Those who accept the pedagogical reality assumption are also likely to accept local reality. Ostriches do not bury their heads in the sand either.