Dear Dr. Boli: I was talking to some guy on the streetcar, and he said that artificial intelligence isn’t really intelligent because it doesn’t meet the definition of intelligence. But he said I’d have to pay him twenty bucks to hear what the definition of intelligence is, and I didn’t have twenty bucks with me. So I figured I’d ask you, since you seem to answer questions for free: What is the definition of “intelligence”? —Sincerely, Ardis Wallslair McFurtle, Stowe Township.

Dear Madam: Intelligence is the quality that separates human beings from machines or animals. That is the only definition of “intelligence” that is of any permanent value. Specific criteria may be mentioned in some academic definitions of “intelligence,” but when we come across a machine or animal that meets those criteria, we change the criteria. The ability to make and use tools has been rejected as a criterion, because crows and apes can do that, and obviously they are not really intelligent. The ability to make reasoned arguments has been rejected, because AI bots can do that, and obviously they are not really intelligent. Eventually intelligence may be found to reside in the small number of genes we do not share with the chimpanzees. But, meanwhile, “the quality that separates human beings from machines or animals” is a reliable permanent definition, because it will not change no matter how much the facts have to be revised to fit it.