John McCarthy

1927-

American Computer Scientist

The father of research in artificial intelligence (AI)—a term he coined—John McCarthy wrote the principal computer language for AI research, List Processing Language (LISP). He founded two of the most important AI laboratories in the world, and in latter years has been active in the movement for an "Electronic Bill of Rights" to govern electronic communications.

Born in Boston, Massachusetts, on September 4, 1927, McCarthy was the elder of two brothers. His father, John Patrick McCarthy, worked variously as a carpenter, fisherman, union organizer, and inventor; and his mother, Ida Glatt, was a Jewish Lithuanian involved in the suffrage movement, the effort to secure the vote for women. Both were members of the Communist Party of America, and McCarthy grew up in a politically charged atmosphere.

A sickly child, McCarthy turned to books for solace, and eventually his family moved to Los Angeles in hopes that his health would improve. It did, and in the meantime he proved to be a prodigious scholar, skipping three grades and entering the California Institute of Technology (Cal Tech) in 1944. Despite the fact that he took time off from school for a number of reasons, including a stint in the army as a clerk, McCarthy graduated four years later with a degree in mathematics.

He went on to Princeton, where he earned his doctorate in mathematics and took a position as an instructor in 1951. Two years later McCarthy returned to the West Coast, where he worked as an acting assistant professor of mathematics at Stanford University; but in 1955 he took a job back east again, this time at Dartmouth College. Though his time at the latter school lasted for only three years, this would prove to be a pivotal juncture in his career.

In the summer of 1956 McCarthy began working on a program that would assist a computer in playing chess. To limit the possible moves and thus speed up the game, McCarthy developed a method later termed the alpha-beta heuristic, which made it possible for a computer to quickly eliminate any moves that would benefit its opponent. This was the birth of artificial intelligence, a term McCarthy coined that year when he organized the world's first conference on modeling intelligence in computers.

McCarthy became an associate professor of mathematics at the Massachusetts Institute of Technology (MIT) in 1958, and soon founded the first AI laboratory there. He also began creating the computer programming language that would eventually be called LISP, or List Processing Language. This remains the most commonly used language in AI research. While at MIT McCarthy began developing the means of interactive time-sharing on computers, which would make networks possible by allowing hundreds or thousands of people to share data on the same large computer. He also initiated work on the concept of giving a computer "common sense," an idea that would continue to perplex computer programmers for many decades.

McCarthy married the first of his two wives at MIT, and they had a daughter, Susan. In 1962 they moved to Stanford, where he took a professorship in computer science and inaugurated a second AI lab. At Stanford he focused on issues such as the role played by mathematical logic and common sense, which he called nonmotonic reasoning, in AI. He also examined questions such as that of a machine that could copy itself, or of an AI more intelligent than its creator.

Divorced in the 1960s, McCarthy married Vera Watson, a computer programmer and world-class mountain climber, with whom he had two more children, Sarah and Timothy. McCarthy himself was extremely active, taking part in outdoor activities such as rock-climbing, flying, and even skydiving. Tragically, his wife's own adventurous quests ended in misfortune: Watson died while taking part in a women's expedition in the Himalayas.

Though McCarthy has professed disillusionment both with the Marxism of his parents and with some of the leftist groups with which he associated in the 1960s, he has remained politically active. He was one of the first to propose that the U.S. Constitution's Bill of Rights be extended to guarantee the rights of each person to read, correct, and limit access to their own electronic files. Among the honors McCarthy has received are the Alan Mathison Turing Award (1971), the Kyoto Prize (1988), and the National Medal of Science (1990). In 1987 he took the Charles M. Pigott chair at the Stanford University School of Engineering.

JUDSON KNIGHT