John McCarthy (computer scientist)

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Lore & Background

John McCarthy was born in Boston, Massachusetts, on September 4, 1927, to an Irish immigrant father and a Lithuanian Jewish immigrant mother. The family relocated frequently during the Great Depression before settling in Los Angeles. Both parents were active Communist Party members who encouraged learning and critical thinking. McCarthy graduated from Belmont High School two years early and was accepted into Caltech in 1944. He was suspended from Caltech for failure to attend physical education courses, served in the US Army, and was readmitted, receiving a BS in mathematics in 1948. He completed his PhD in mathematics at Princeton in 1951 under Donald C. Spencer. After short-term appointments, he became an assistant professor at Dartmouth in 1955, moved to MIT in 1956, and became a full professor at Stanford in 1962, remaining until his retirement in 2000. He was married three times; his second wife Vera Watson died in 1978 attempting to scale Annapurna I Central, and he later married computer scientist Carolyn Talcott. McCarthy declared himself an atheist and became a conservative Republican after a visit to Czechoslovakia in 1968 following the Soviet invasion. He died at his home in Stanford on October 24, 2011.

Reader's Guide

John McCarthy's significance lies in his foundational role in artificial intelligence. In 1958, he proposed the advice taker, which inspired later work on question-answering and logic programming. In the late 1950s, he discovered that primitive recursive functions could be extended to compute with symbolic expressions, producing the Lisp programming language, which became the standard for AI applications after its publication in 1960. Around 1959, he invented garbage collection methods to solve problems in Lisp. He served on the ACM ad hoc committee that designed ALGOL 60, proposing the use of recursion and conditional expressions. McCarthy was instrumental in creating three of the earliest time-sharing systems: Compatible Time-Sharing System, BBN Time-Sharing System, and Dartmouth Time-Sharing System. In 1961, he suggested the idea of utility computing, anticipating cloud computing. From 1978 to 1986, he developed the circumscription method of non-monotonic reasoning. In 1982, he originated the idea of the space fountain. He advised 30 PhD graduates and received the 1971 Turing Award, the National Medal of Science, and the Kyoto Prize.

Did You Know?

• McCarthy was fluent in Russian and made friends with Russian scientists during trips to the Soviet Union, but distanced himself after visiting the Soviet Bloc.
• He was suspended from Caltech for failing to attend physical education courses, then served in the US Army before being readmitted.
• His colleague Lester Earnest said that the Internet would not have happened nearly as soon except for McCarthy initiating the development of time-sharing systems.
• McCarthy's 2001 short story 'The Robot and the Baby' explored whether robots should have emotions and anticipated aspects of Internet culture and social networking.
• His Usenet signature block for years read: 'He who refuses to do arithmetic is doomed to talk nonsense.'