title: Erratum.
abstract: In William Shea's review of Maurice A. Finocchiaro's Galileo and the Art of Reasoning (15 May, p. 780), the third symbol in the passage quoted from the book should have been "A12." The first sentence of the passage quoted from Galileo's Dialogue on the Two Chief World Systems should have read, "The art of demonstration is learned by reading works which contain demonstrations."