1927: John McCarthy is born

On 4 September 1927, John McCarthy was born in Boston, Massachusetts. The son of an Irish immigrant father and a Lithuanian Jewish mother, he grew up during the Great Depression and showed an early gift for mathematics. By his teens he had taught himself calculus from a textbook; later, at Caltech and Princeton, he absorbed the formal logic and computability theory that would shape his life's work.

In 1955 McCarthy coined the phrase “artificial intelligence” while drafting the proposal for the Dartmouth Summer Research Project. The 1956 workshop that followed is widely regarded as the field’s founding moment. He went on to invent the Lisp programming language (1958), whose symbolic-list processing and garbage collection remain foundational to AI systems. He also pioneered time-sharing operating systems, enabling interactive computing long before personal computers existed, and formulated the situation calculus—an early logical framework for representing actions and change that still influences automated planning and knowledge representation.

McCarthy’s vision was ambitious yet precise: he believed machines could achieve human-level intelligence through formal reasoning about the world. He spent decades refining non-monotonic logics and common-sense reasoning, arguing that AI needed not only statistical pattern matching but also the ability to handle incomplete information the way people do. Though some of his grander goals remain unfulfilled, his insistence on mathematical clarity helped keep the field intellectually rigorous.

Today’s large language models, robotic planners, and knowledge graphs all descend, in part, from the conceptual toolkit McCarthy assembled. Lisp dialects still power research prototypes; situation-calculus ideas appear inside modern planners; and the very name “artificial intelligence” continues to define a global research and industrial enterprise. On the anniversary of his birth we remember a thinker who gave the field both its label and many of its enduring methods.