A Universe from Nothing?

Universefromnothing-198x300Sean Carroll in Cosmic Variance:

Some of you may have been following a tiny brouhaha (“kerfuffle” is so overused, don’t you think?) that has sprung up around the question of why the universe exists. You can’t say we think small around here.

First Lawrence Krauss came out with a new book, A Universe From Nothing: Why There Is Something Rather Than Nothing (based in part on a popular YouTube lecture), which addresses this question from the point of view of a modern cosmologist. Then David Albert, speaking as a modern philosopher of science, came out with quite a negative review of the book in the New York Times. And discussion has gone back and forth since then: here’s Jerry Coyne (mostly siding with Albert), the Rutgers Philosophy of Cosmology blog(with interesting voices in the comments), a long interview with Krauss in the Atlantic, comments by Massimo Pigliucci, andanother response by Krauss on the Scientific American site.

I’ve been meaning to chime in, for personal as well as scientific reasons. I do work on the origin of the universe, after all, and both Lawrence and David are friends of the blog (and of me): Lawrence was our first guest-blogger, and David and I did Bloggingheads dialogues here and here.

Executive summary

This is going to be kind of long, so here’s the upshot. Very roughly, there are two different kinds of questions lurking around the issue of “Why is there something rather than nothing?” One question is, within some framework of physical laws that is flexible enough to allow for the possible existence of either “stuff” or “no stuff” (where “stuff” might include space and time itself), why does the actual manifestation of reality seem to feature all this stuff? The other is, why do we have this particular framework of physical law, or even something called “physical law” at all? Lawrence (again, roughly) addresses the first question, and David cares about the second, and both sides expend a lot of energy insisting that their question is the “right” one rather than just admitting they are different questions. Nothing about modern physics explains why we have these laws rather than some totally different laws, although physicists sometimes talk that way — a mistake they might be able to avoid if they took philosophers more seriously. Then the discussion quickly degrades into name-calling and point-missing, which is unfortunate because these are smart people who agree about 95% of the interesting issues, and the chance for productive engagement diminishes considerably with each installment.