Saturday, August 13, 2005

Summer Break

I'm taking a break from my rigorous once a week (at most) blogging schedule. My beach reading assignment is David Lewis. Here's a naive question: should one's opinion of modal realism be influenced by the fact that physicists for their own reasons are increasingly postulating the existence of multiple worlds?


Clayton Littlejohn said...

I suspect not (note: suspect). Lewis' motivations for the postulation of a plurality of worlds are quite different from the physicists and I thought that whereas Lewis thinks worlds must be causally isolated, I thought that some physicists postulate worlds that are causally connected at some point in their history. But this is a suspicion, I'm not an expert in either modal metaphysics or fancy physics

Steve said...

Thanks Clayton. I think you're right, there isn't much connection here, given the completely different motivations.

On the physics side, though, I was interested to read lately that some string theorists now talk about a "landscape" of either an infinite or finite but huge (10^500) number of solutions to string theory. We just happen to live in one.

I think probably the idea from physics closest to modal metaphysics is the original "many worlds" interpretation of quantum mechanics (due to Everett). Here the possibilities implied by the wave function are manifest through multiple worlds (although they would be a branching system of worlds, which is rejected by Lewis in favor of distinct worlds, which contain duplicates, but not actually overlapping parts).