John McCarthy — Coiner of "artificial intelligence" and designer of LISP

John McCarthy (4 September 1927 — 24 October 2011) rewrote the premises of computer science twice. The first occasion was in 1955, when the proposal he co-authored for a 1956 summer workshop introduced the phrase "artificial intelligence" into the literature. The second was in 1958, when he designed LISP. Both the name and the language survive seventy years later.

Background

McCarthy was born in Boston, Massachusetts. His parents — Irish and Lithuanian-Jewish, respectively — were active left-wing organisers and were for a time members of the Communist Party USA. His mathematical precocity showed in his early teens; he taught himself from Caltech textbooks while still in high school.

He took his BS in mathematics at Caltech (1948) and his PhD at Princeton (1951) under Solomon Lefschetz. After appointments at Stanford (1953-55), Dartmouth (1955-58), and MIT (1958-62), McCarthy returned to Stanford as a professor of computer science in 1962. In 1965 he founded the Stanford Artificial Intelligence Laboratory (SAIL), which he led until 2000.

The Dartmouth workshop and the term "artificial intelligence"

In August 1955 McCarthy, together with Marvin Minsky, Claude Shannon, and Nathaniel Rochester (IBM), submitted a funding proposal to the Rockefeller Foundation for a workshop the following summer. Titled "A Proposal for the Dartmouth Summer Research Project on Artificial Intelligence" and pitched as "a 2 month, 10 man study of artificial intelligence", it is the first known use of the phrase in a formal document.

The Dartmouth workshop of summer 1956 gathered roughly ten researchers for a six-week residency. Its output was less a body of new results than a conceptual agreement — that the study of machine simulation of intelligence deserved status as an independent field. McCarthy himself produced little technical work in the room, but the act of naming placed him at the top of any AI history written since.

The design of LISP

LISP (LISt Processor), designed at MIT in 1958, was announced in McCarthy's paper "Recursive functions of symbolic expressions and their computation by machine, Part I" in the April 1960 Communications of the ACM. LISP introduced three innovations together: (1) the unified representation of code and data through S-expressions, (2) an evaluation model in which recursive functions are first-class citizens, and (3) automatic memory management — garbage collection.

The term "garbage collection" itself is McCarthy's coinage. The concept passed into Java (1995), Python (1991), Go, JavaScript, and most of the languages in widespread use today.

LISP dominated AI research from the 1960s into the 1980s and spawned a lineage of descendants — Maclisp, Common Lisp, Scheme, Clojure — and, more broadly, the entire functional programming tradition.

Timesharing and "computing as a utility"

McCarthy's third contribution was the proposal of timesharing, which he sketched in a 1959 memo and which let multiple users share a single large machine. The idea came directly to fruition in MIT's CTSS (1961) and Multics (1969); UNIX (1969) sits in the same lineage.

At MIT's centennial in 1961 McCarthy went further, suggesting that "computation may someday be organised as a public utility, just as the telephone system is a public utility". AWS in 2006 vindicated him forty-five years later — long before the term "cloud computing" entered common use.

Awards and honours

• 1971 ACM Turing Award, "for contributions to artificial intelligence"
• 1988 Kyoto Prize in Advanced Technology
• 1990 National Medal of Science (United States)
• 2003 Benjamin Franklin Medal in Computer and Cognitive Science

Legacy

McCarthy died at his Stanford home on 24 October 2011, aged 84, of natural causes. Steve Jobs had died at the start of the same month and Dennis Ritchie earlier within it, leaving October 2011 as a month of three successive computing losses.

His technical inheritance runs along two tracks. One is the LISP / garbage-collection lineage: nearly every high-level language in use today inherits its abstraction level from McCarthy's 1958 design. The other is artificial intelligence itself. McCarthy's stated goal — human-level general intelligence — became the field's pole star for more than half a century, from the deep-learning revolution of AlexNet (2012) to ChatGPT (2022). McCarthy personally preferred logic-based symbolic methods to statistical learning and remained sceptical of neural approaches, but his decision to keep the banner of "AI" flying provided the bridge that subsequent waves of researchers walked across.