The basic idea of computing—that is, the use of machines to perform tasks that require "intelligence"--is not new. Adding machines and the like have existed for generations now. In the early nineteenth century, a chess-playing machine was the rage, and was demonstrated to the French ruler Napoleon Bonaparte. That the machine was later shown to be fraudulent (as it repeated the moves of a hidden human operator) did not lessen the desire of humans to build and use intelligent devices. Later in the nineteenth century, the Englishman Charles Babbage designed a computer he called the Analytical Engine.

However, if one thinks about it, there are a great many tasks requiring some modicum of skill that one could ask a machine to perform. To have a separate machine for each such task is clearly too expensive. Even if one could afford the expense, the...