Ask Alexa who coined the term “artificial intelligence,” and she’ll tell you John McCarthy. As a computer pioneer, John McCarthy provided the world with much more than a name for AI. He also developed the LISP programming language, one of the oldest programming languages still in use today.
Unveiled in an April 16, 1959, presentation, LISP is known for its applications within (you guessed it) artificial intelligence. LISP is short for LISt Processing. As McCarthy wrote in this 1979 paper, what made LISP different was its use of symbolic expressions rather than numbers. Instead of relying on a sequence of procedural steps, a LISP program applies a function to data, making use of parentheses to list operations. McCarthy was involved in artificial intelligence work at the Massachusetts Institute of Technology, and because LISP’s structure was uniquely suited to artificial intelligence, LISP became the language of choice for AI work. LISP’s sentence-based structure allowed machines to “reason” with declarative knowledge.
In addition, McCarthy wrote: “LISP still has operational features unmatched by other language that make it a convenient vehicle for higher level systems for symbolic computation and for artificial intelligence. These include its run-time system that gives good access to the features of the host machine and its operating system, its list structure internal language that makes it a good target for compiling from yet higher level languages, its compatibility with systems that produce binary or assembly level programs, and the availability of its interpreter as a command language for driving other programs.”
In a 1959 memo, McCarthy was also the first to describe the concept of timesharing, leading to the development of a timesharing system at MIT. In 1962, McCarthy left MIT for Stanford University, where he continued his work and commentary on AI until his death in 2011.