String-Theory Wars

Since the 1980s, string theory has emerged as the leading candidate for achieving every physicist's dream: reconciling general relativity with quantum mechanics and thereby finding a tidy explanation for all of nature's forces — a so-called Theory of Everything. One problem: String theory has yet to be verified.

Two new books have cast a hot, critical light on the validity of string theory. Lee Smolin and Peter Woit both argue that string theorists have never generated any