People tend to think that only extreme versions of things pose deep problems. That’s why few people see modeling the creativity of, say, the trite television character of Archie Bunker as a difficult task. It’s strange and disorienting to realize that if we could write a program that could compose Muzak or write trashy novels, we would be 99 percent of the way to mechanizing Mozart and Einstein. Even a program that could act like a mentally retarded person would be a huge advance. The commonest mental abilities—not the rarest ones—are still the central mystery.