Computers generated a great deal of excitement in the 1950s when they began to beat humans at checkers and to prove math theorems. In the 1960s the hope grew that scientists might soon be able to replicate the human brain in hardware and software and that “artificial intelligence” would soon match human performance on any task. In 1967 Marvin Minsky of the Massachusetts Institute of Technology, who died earlier this year, proclaimed that the challenge of AI would be solved within a generation.