Why Does the World Exist?
A simple question proves thorny in Jim Holt's new book.
(Page 3 of 5)
Of course, as a complete answer to the question of our universe's existence, this faces the same old regress problem: if our universe grew out of another one, where did the other universe come from? (Essentially the same point can be made about Alex Vilenkin's view, which also involves cosmic inflation and allows that from an initial state of nothingness, "a tiny bit of energy-filled vacuum could spontaneously 'tunnel' into existence…[and then] undergo a runaway expansion. In a couple of microseconds it would attain cosmic proportions, issuing in a cascading fireball of light and matter -- the Big Bang!")Skip to next paragraph
Subscribe Today to the Monitor
No one has yet succeeded, then, in explaining how something could literally come out of nothing: in every case some sort of prior condition needs to be presupposed. Perhaps, though, it is the very idea of "something coming out of nothing" that is at fault. Why not just say, as David Hume suggested, that the universe has always been around, and that the existence of the universe at each moment in time is explained by its existence in the previous moment? Accepting this as the final explanation, of course, involves giving up on the idea that the existence of the universe as a whole can be explained; rather, we would have to accept its existence as a kind of brute fact. But should this bother us?
It doesn't bother me much, to be honest, but it does bother Holt. "Intellectually," he writes, the brute-fact view feels like throwing in the towel. It's one thing to reconcile yourself to a universe with no purpose and no meaning – we've all done that on a dark night of the soul. But a universe without an explanation? That seems an absurdity too far, at least to a reason-seeking species like ourselves. …A world that existed for no reason at all -- an irrational, accidental, "just there" universe -- would be an unnerving one to live in. So, at least, claimed the American philosopher Arthur Lovejoy. In one of his 1933 lectures at Harvard on the "Great Chain of Being," Lovejoy declared that such a world "would have no stability or trustworthiness; uncertainty would infect the whole, anything (except, perhaps, the self-contradictory) might exist and anything might happen, and no one thing would be in itself even more probable than any other."
The first thing to say is that Lovejoy is making at least one error of logic here, by confusing the question of how (and whether) the universe began with the question of what the universe is like. That the universe's existence is irrational (in the sense that it has no ultimate explanation) does not entail that the universe must behave irrationally. The idea that a logical and predictable universe has simply always existed is no more mystifying and no less probable than the idea that a chaotic and fundamentally unpredictable universe might simply always have existed. To think otherwise is to commit the error of thinking that we can use pure reason, unguided by empirical evidence, to determine what a universe is likely to be like.