Allan Gibbard

Allan Fletcher Gibbard (born 1942) is the Richard B. Brandt Distinguished University Professor of Philosophy Emeritus at the University of Michigan, Ann Arbor. Soon after his doctoral degree, Gibbard provided a proof of a conjecture that strategic voting was an intrinsic feature of non-dictatorial voting systems with at least three choices, a conjecture of Michael Dummett and Robin Farquharson. This work would eventually become known as "Gibbard's theorem", published in 1973. This theorem built on Kenneth Arrow's work on "Arrow's impossibility theorem", published in 1951, for which Arrow (and Sir John Richards Hicks) won the won the Nobel prize in Economics in 1972.

Mark Satterthwaite later worked on a similar theorem to Gibbard's which he published in 1975. Satterthwaite and Jean Marie Brin published a paper in 1978 describing Gibbard's and Satterthwaite's mathematical proofs as the "Gibbard–Satterthwaite theorem" and described its relationship to Arrow's impossibility theorem.

Gibbard has also made major contributions to contemporary ethical theory, in particular metaethics, where he has developed a contemporary version of non-cognitivism. He has also published articles in the philosophy of language and metaphysics.