The rise of the machines

Last month a computer program called AlphaGo took on one of the greatest players of the complex board game, Go, and beat him four games to one. Lee Sedol, the South Korean Go master, lost 1 million, offered as prize money by Google, the challenger's proprietor. But, more momentously, his humbling has taken the battle of wits between machines and humans to yet another level. To be sure, this isn't the first time software has got the better of an exceptionally clever human. In 1997, IBM's Deep Blue had checkmated Garry Kasparov, the erstwhile world chess champion.