The Library

Systematic analysis of influential public arguments. We criticize reasoning, not identities; we present the strongest version of each argument; and we mark clearly where evidence ends and interpretation begins.

• Deep analysisRests on an equivocation

  What Do Physicists Mean by “Nothing”?

  A quantum vacuum is a remarkable thing — but it is not the philosopher's nothing, and the gap between the two is where Lawrence Krauss's boldest claim needs more than physics.

  Lawrence Krauss's A Universe from Nothing (2012) argues that modern physics can explain how a universe arises from “nothing,” and presents this as bearing on the ancient question of why there is something rather than nothing. The physics it describes is legitimate and genuinely illuminating: a quantum vacuum is not inert, and given the laws of physics a universe's worth of matter can appear at no net energy cost. But the book's headline claim trades on an equivocation. The “nothing” from which physics builds a universe — a quantum vacuum, or even a state without space and time — is a physical arrangement governed by physical law; it is not the philosopher's “nothing,” the absence of any physical reality whatsoever. The critique is not ours alone: the philosopher of physics David Albert, himself no friend of theism, pressed it in The New York Times. And none of it shows that a creator is required — the deeper question may be ill-posed, or may bottom out in brute facts. The book answers a narrower, if fascinating, question than its title advertises.