John McCarthy

Overview

John McCarthy (1927–2011) was an American computer scientist who helped found artificial intelligence as a research field. He created a programming language that became widely used in AI research, and he took part in developing the early ideas behind time-sharing computers. He was born in Boston, Massachusetts, on 4 September 1927, and died at Stanford, California, on 24 October 2011.^[3]

Education and academic posts

McCarthy graduated from the California Institute of Technology in 1948 and received a PhD in mathematics from Princeton University in 1951.^[1]

His academic posts included Higgins Research Instructor at Princeton (1951), acting assistant professor at Stanford (1953), and assistant professor at Dartmouth College (1955). He then became an assistant professor at MIT in 1958 and an associate professor there in 1961. He moved to Stanford as a professor in 1962, and Wikipedia records that he retired in 2000.^[1][3]

The Dartmouth proposal

While at Dartmouth, McCarthy led a proposal, dated August 1955, for a summer research project in 1956 on “artificial intelligence”. He wrote it with Marvin Minsky, Nathaniel Rochester and Claude Shannon. The document is credited with coining the term. McCarthy then organised the 1956 Dartmouth workshop, which brought researchers together to work on the project.^[2]

LISP

McCarthy created LISP, a programming language for symbolic processing. Symbolic processing means working with symbols, lists and nested expressions rather than mainly with numbers. That suited AI, where programs often need to handle words, facts and rules. LISP became widely used in AI research. He described it in the 1960 Communications of the ACM paper “Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I”.^[3]

Time-sharing and memory management

McCarthy proposed the basic concept of time-sharing, in which one computer serves many users by rapidly switching between their programs, and he took part in developing such systems. Wikipedia also credits him with inventing garbage collection around 1959, the automatic reclaiming of memory that a program no longer uses.^[3]

Common sense reasoning

In 1958 McCarthy gave the paper “Programs with Common Sense” at the Teddington Conference on the Mechanization of Thought Processes, and it was printed in the conference proceedings.^[5] With it he began a long line of work on common sense reasoning. The goal was to formalise the logic of everyday inference so that computers could reason more like people. Everyday reasoning often reaches conclusions that are usually right but can be overturned by new information. For example, a person may assume a bird can fly until told otherwise. Writing that kind of default reasoning as precise logic is a hard problem, and it remained a theme of his later work.^[3]

Leading AI research

According to the Kyoto Prize biography, McCarthy established MIT’s first AI research project in 1958 and later founded the AI laboratory at Stanford.^[1]

With Donald Michie and Richard Gregory, he debated Sir James Lighthill about the Lighthill report at the Royal Institution, in a debate broadcast on BBC TV in June 1973.^[4] That report was a British review that criticised AI research in the UK.

Awards

He received the ACM A. M. Turing Award in 1971, the Kyoto Prize in Advanced Technology in 1988, the U.S. National Medal of Science in 1990 and the Benjamin Franklin Medal in 2003.^[1][3]

Legacy

McCarthy’s name is attached to several foundations of the field: the 1955 proposal that gave AI its name, the LISP language, the early design ideas of time-sharing, and the study of common sense reasoning. The Dartmouth workshop he organised is often treated as the starting point of AI as an organised research field.