Textbook of AI

1950–2023, AI researcher; founder of CYC

Also known as: Douglas B. Lenat

Douglas Bruce Lenat was an American AI researcher whose 1976 Stanford PhD thesis produced AM (Automated Mathematician) and whose later EURISKO extended the same heuristics-driven discovery methodology. AM "discovered" mathematical concepts, including some genuinely novel ones, by applying transformation heuristics to a small initial set of mathematical primitives. EURISKO won the Trillion Credit Squadron tournament of the Traveller role-playing game two years running by evolving novel naval-warfare strategies.

In 1984 Lenat launched CYC, an enormous project to encode the entirety of human commonsense knowledge in a logical knowledge base. The project, run as Cycorp from 1994, ran for nearly forty years and accumulated tens of millions of axioms before Lenat's death in 2023. CYC was the most ambitious, and most controversial, knowledge-engineering project in the history of AI; the research community has long disagreed about how successful it was. With the rise of large language models, which encode commonsense knowledge implicitly through scaled pre-training, the open question is whether CYC's explicit knowledge offers anything LLMs lack, Lenat argued, in late papers, that it does.