“Why is there something rather than nothing? It’s a classic puzzle that’s getting a lot of attention now. Sean Carroll has just posted his opinion on the arXiv—he’s decided there’s no answer. Here’s his abstract:
It seems natural to ask why the universe exists at all. Modern physics suggests that the universe can exist all by itself as a self-contained system, without anything external to create or sustain it. But there might not be an absolute answer to why it exists. I argue that any attempt to account for the existence of something rather than nothing must ultimately bottom out in a set of brute facts; the universe simply is, without ultimate cause or explanation.