John McCarthy

John McCarthy (1927-2011) is a legendary person in the fields of computer science and AI (artificial intelligence). Primarily known as the creator of one of the longest-lived computer languages in use—LISP (in 1958), McCarthy was one of the first people, to be interested in AI (since 1948) and coined the term in 1955. He also developed the concept of timesharing in the late fifties and early sixties. McCarthy made also substantial contributions to the theory of computation and knowledge representation.

McCarthy’s idea for AI originated in September 1948, when he went to the Hixon Symposium on Cerebral Mechanisms in Behavior, a conference that joined together leading researchers in different areas related to cognitive science, including famous psychologist Karl Lashley, as well as mathematicians Alan Turing and Claude Shannon. As McCarthy listened to the discussions comparing computers and the brain, he had a watershed moment. From that time on, his chief interests related to the development of machines that could think like people.

In the 1950s, McCarthy was not the only researcher, dabbling in what would be called artificial intelligence. There were several scientists (including Marvin Minsky, Herbert Simon, Allen Newell, and Oliver Selfridge) working in this field. What distinguished McCarthy’s work was his emphasis on using mathematical logic both as a language for representing the knowledge that an intelligent machine should have and as a means for reasoning with that knowledge. This emphasis on mathematical logic led to the development of the logicist approach to artificial intelligence, as well as the development of the computer language LISP in 1958.

The other difference between McCarthy’s approach to AI and others was that previous work in AI had focused on getting a computer to replicate activities that are challenging for humans, such as playing chess and proving theorems of mathematics. In contrast, McCarthy was concerned with mundane and seemingly trivial tasks, such as constructing a plan to get to the airport.

McCarthy maintained that there were aspects of the human mind that could be described precisely enough to be replicated: “The speeds and memory capacities of present computers may be insufficient to simulate many of the higher functions of the human brain,” he wrote in 1955, “but the major obstacle is not lack of machine capacity but our inability to write programs taking full advantage of what we have.”

The term “artificial intelligence” was proposed by McCarthy in 1955 when he began writing (with Minsky, Shannon, and Nathaniel Rochester), the proposal to fund the first conference dedicated to the topic—the famous Dartmouth Conference on Artificial Intelligence, which took place in the summer of 1956.

In 1961, McCarthy was the first to publicly suggest that computer timesharing technology might lead to a future in which computing power and even specific applications could be sold through the utility business model (just like water or electricity). He claimed that “computing may someday be organized as a public utility”. This idea of a computer or information utility became very popular in the late 1960s but faded by the mid-1990s. At the beginning of the 2000s however, the idea resurfaced in new forms (cloud services).

In 1966, McCarthy hosted a series of four simultaneous computer chess matches carried out via telegraph against rivals in the Soviet Union (see the lower photo). Although helped pioneer computer chess, he came to think the game was a distraction for programmers.

During the 1970s McCarthy presented a paper on buying and selling by computer, prophesying what has become known as e-commerce. He also invited a local computer hobby group, the Homebrew Computer Club, to meet at Stanford. Its members included Steve Jobs and Steven Wozniak, who later would go on to found Apple Inc. However, his own interest in developing time-sharing systems led him to underestimate the potential of personal computers. When the first PCs emerged in the 1970s he dismissed them as “toys”.

In 1958, McCarthy specified LISP (the name derives from “LISt Processing”)—the second-oldest high-level programming language in widespread use today (only Fortran of John Backus is older, by one year). Like Fortran, Lisp has changed a great deal since its early days, and a number of dialects have existed over its history. Today, the most widely known general-purpose Lisp dialects are Common Lisp, Scheme, and Clojure. Linked lists are one of LISP languages’ major data structures, and its source code is itself made up of lists.

Originally created as a practical mathematical notation for computer programs, LISP is based on the notation of Alonzo Church‘s lambda calculus. It quickly became the favored programming language for AI research. As one of the earliest programming languages, Lisp pioneered many ideas in computer science, including tree data structures, automatic storage management, dynamic typing, and the self-hosting compiler.

In some of his papers like Free Will—Even for Robots, and Deterministic Free Will, McCarthy explored ideas of robot decision-making. He wrote a science fiction story, The Robot and the Baby, to “partly illustrate my opinions about what household robots should be like”. His robot’s reasoning is displayed in a Lisp-like manner as R781 decides to simulate love for Travis, the human baby. The story includes lines such as “(Required (Not (Cause Robot781) (Believes Travis (Person Robot781))))”. The computer industry joke is that Lisp actually stands for Lots of Irritating Single Parentheses.

In 1982 McCarthy appears to have originated the idea of the space fountain, a form of “space elevator”, a tremendously tall non-static active structure (tower) extending up from the ground.

Biography of John McCarthy

John McCarthy was born in Boston, Massachusetts, on 4 September 1927, to John Patrick McCarthy (15 Sep 1896-24 May 1963) (born in San Francisco to an Irish Catholic immigrant family) and Ida Glatt-McCarthy (18 Nov 1893-23 Oct 1957) (Lithuanian Jewish origin), who married in 1922. Ida Glatt was born in Taurogen, Lithuania (then part of Imperial Russia) and immigrated to the United States in 1900 with her mother and sister.

When the Great Depression started at the beginning of the 1930s, McCarthy’s parents lost their house, and the family (which now included a second child, Patrick), became briefly peripatetic. They lived for a short while in New York and then in Cleveland, before finally settling in Los Angeles (in part because of John’s respiratory problems), where the senior John McCarthy was hired as a labor organizer for the Amalgamated Clothing Workers and developed a hydraulic orange juice squeezer. Ida McCarthy worked as a journalist and had been active in the women’s suffrage movement and both parents of John were active members of the US Communist Party.

Like many child prodigies, John McCarthy was partly self-educated. Due to childhood illness (respiratory problems), he began school a year late, but he quickly made up the time on his own, skipped several grades and wound up graduating from Belmont High School in Los Angeles two years early, in 1943.

As a teenager, McCarthy developed an interest in mathematics and decided he wanted to go to the CalTech—California Institute of Technology. In his application to CalTech, he wrote a one-sentence statement of purpose: “I intend to be a professor of mathematics.”

Receiving a B.S. in Mathematics in 1948, McCarthy initially continued his graduate studies at Caltech, but in 1949 moved to Princeton University, where he received a Ph.D. in Mathematics in 1951.

McCarthy remained as an instructor at Princeton from 1951 until 1953 when he came to Stanford as an assistant professor. In 1955, he left for Dartmouth and then for MIT before returning to Stanford in 1962 as a full professor of computer science, where he stayed until his retirement almost 40 years later.

John McCarthy was honored with the Kyoto Prize in 1988, the National Medal of Science in 1990, & the Benjamin Franklin Medal in 2003. He was inducted into the “IEEE Intelligent Systems” AI’s Hall of Fame in 2011.

McCarthy was married three times. His first wife was Martha Coyote, and they had two daughters Susan and Sarah. His second wife was Vera Watson, a programmer, and mountaineer who died in 1978 attempting to scale Annapurna as part of an all-women expedition. He later married Carolyn Talcott, a computer scientist at Stanford, and they had a son, Timothy Talcott.

John McCarthy died on 24 October 2011, in Palo Alto, California, of heart failure.