John L. Pollock
Also known as John Leslie Pollock
John L. Pollock was an American philosopher who built his theory of defeasible reasoning into OSCAR, an architecture for artificial rational agents. Trained in physics, philosophy and mathematics at the University of Minnesota, he earned a philosophy PhD at Berkeley in 1965 and joined the University of Arizona in 1978, where he helped found the Interdisciplinary Cognitive Science Program and became Regents Professor of Philosophy and Cognitive Science. His 1974 book Knowledge and Justification brought defeasibility into the philosophical mainstream; in 1995, he set out the theory behind the OSCAR Project, funded in part by the National Science Foundation, and its general-purpose defeasible reasoner in Cognitive Carpentry. He died in 2009, and the journal Argument & Computation dedicated a special issue to his memory.
Timeline
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1940–1961
Physics, philosophy and mathematics
Born in Atchison, Kansas, in 1940, he graduates from St. Louis Park High School in 1958. He earns his bachelor's degree at the University of Minnesota in 1961 with majors in physics, philosophy and mathematics.
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1965–1978
A Berkeley PhD in philosophy
In 1965, he completes a philosophy PhD at the University of California, Berkeley, with the dissertation Analyticity and Implication, advised by Ernest Adams; its appendix on defeasible reasoning grows into his main contribution to philosophy. He then holds faculty posts at SUNY Buffalo, the University of Rochester and the University of Michigan.
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1974
Knowledge and Justification
Princeton publishes Knowledge and Justification in 1974. The book establishes him in epistemology, and its epistemic norms, governed by defeasible reasoning, bring defeasibility into the philosophical mainstream.
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1978–2009
Regents Professor at Arizona
He joins the University of Arizona in 1978 and helps found its Interdisciplinary Cognitive Science Program. His work on computational models of reasoning raises him to Regents Professor of Philosophy and Cognitive Science.
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1987–1989
Undercutting and rebutting defeat
In 1987, he publishes "Defeasible reasoning" in Cognitive Science, and his distinction between undercutting and rebutting defeat becomes a fixture of the field. In 1989, "OSCAR: A general theory of rationality" appears in the Journal of Experimental and Theoretical Artificial Intelligence.
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1995
Cognitive Carpentry and OSCAR
He directs the OSCAR Project, funded in part by the National Science Foundation, which builds an artificial rational agent around a general-purpose defeasible reasoner implemented in LISP. Bradford/MIT Press publishes its theory in Cognitive Carpentry in 1995, and he describes the reasoner as the first able to operate in first-order logic, where consistency is undecidable.
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1998–2000
Reasoning about a changing world
In 1998, Computational Intelligence publishes his "Perceiving and Reasoning about a Changing World", which proposes solutions to the Frame, Qualification and Ramification problems, with the reasoning implemented in OSCAR. In March 2000, he posts a system description of the OSCAR defeasible reasoner for the Nonmonotonic Reasoning Workshop.
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2006–2009
Thinking about Acting
In 2006, Oxford University Press publishes Thinking about Acting, his theory of rational decision making for realistically resource-bounded agents. He dies in September 2009 while Regents Professor of Philosophy and Cognitive Science at Arizona, and the journal Argument & Computation dedicates a special issue to his memory.
Career
- 1978–2009University of ArizonaRegents Professor of Philosophy and Cognitive Science
- University at Buffalo, State University of New YorkFaculty
- University of RochesterFaculty
- University of MichiganFaculty
Education
- 1965University of California, BerkeleyPhD
- 1961University of MinnesotaBachelor's degree
Colleagues
Sources and credits
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