A Big Why Question

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Edward Hessler

I'D LIKE --

I'd like to know 

what this whole show 

is about 

before it's out.

--Piet Hein 

I've used this Grook in at least one other post (maybe others). However, it is a perfect introduction to a very large question.

And the answer to Hein's wish is that we may never know. 

No doubt you have looked up at night--the classic astronomer's pose--and wondered about where this place came from. Was there anything before it?  Where is it going? 

There is some confidence on where we are going in the very, very, very, very long term. Based on considerable evidence the universe will continue it's indefinite expansion leading to the hypothesis known as "the Big Freeze."  There are other hypotheses, of course: the Big Crunch, the Big Change and the Big Rip.  Right now it is going to be cold and dark (but not for a few years). And this will occur long after this planet is here or any of the planets or even the stars.

Theoretician Sean Carroll (CalTech) is a physicist who has been thinking about one of the really big why questions from the beginning of his career.  The question: Why is there something, rather than nothing?

Carroll's thoughtful answer is to be published in the Routledge Companion to the Philosophy of Physics, edited by Eleanor Knox and Alastair Wilson. In the meantime he has posted his penultimate draft in a physics repository known as the arxiv. His answer hasn't changed but in this chapter he notes he has done a much more careful job than previously.  Below is the 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.

Carroll writes a blog (Preposterous Universe) and in the entry notifying readers of this forthcoming publication Carroll has a sentence that is important to understanding how scientists go about their work. "The right question to ask isn’t “Why did this happen?”, but “Could this have happened in accordance with the laws of physics?” This is the question a scientist asks. And Carroll's answer is blunt about our responsibility facing an answer we may not like. "It’s up to us as a species to cultivate the intellectual maturity to accept that some questions don’t have the kinds of answers that are designed to make us feel satisfied."

Carroll's blog entry about this chapter includes access to two previous entries on this topic and to the chapter posted on the physics website, arxiv.  Some of the article makes use of some heavy duty maths (for most of us or maybe just me) but if you want to get an idea of how a physicist thinks about this problem, it is worth skimming the chapter and noting subheadings, dipping in here and there when something attracts you.

For a short profile of Carroll see here.