When an IBM computer program called Deep Blue defeated Garry Kasparov at chess in 1997, wise folk opined that since chess was just a game of logic, this was neither significant nor surprising. Mastering the subtleties of human language, including similes, puns and humor, would remain far beyond the reach of a computer.

Last year another IBM program, Watson, triumphed at just these challenges by winning Jeopardy! (Sample achievement: Watson worked out that a long, tiresome speech delivered by a frothy pie topping was a “meringue harangue.”) So is it time to take seriously the prospect of artificial intelligence emulating human abilities?

The brain may not be incomprehensibly intricate. In fact, it may be a bit like Manhattan. Yes, argues the inventor and futurist Ray Kurzweil in his new book How to Create a Mind. Mr. Kurzweil reckons that a full understanding and simulation of the human brain is a lot closer than most people think. Since he has a more impressive track record of predicting technological progress than most, he deserves to be heard.[…]