John L. Pollock

John Leslie Pollock was an American philosopher born in Atchison, Kansas, on January 28, 1940. He earned degrees in physics, mathematics, and philosophy from the University of Minnesota in 1961, followed by a Ph.D. in philosophy from the University of California, Berkeley in 1965. Pollock held faculty positions at SUNY Buffalo, the University of Rochester, the University of Michigan, and the University of Arizona, where he co-founded the Cognitive Science Program. His doctoral dissertation contained an appendix on defeasible reasoning, which became a central theme in his philosophical work. Pollock's book *Knowledge and Justification* (1974) established his reputation in epistemology, introducing the concept of epistemic norms governed by defeasible reasoning, which allowed for exceptions. He became widely known as a leading figure in defeasible reasoning, influencing fields like artificial intelligence. His other notable works include *How to Build a Person: A prolegomenon* (1989), which explored his AI software project OSCAR, and *Nomic Probability and the Foundations of Induction* (1990). Pollock passed away in 2009.