William of Sherwood was an English logician of the thirteenth century. His works are representative of the consolidation in medieval thought of supposition theory and the treatment of syncategorematic terms with the exposition or analysis of propositions whose logical form is not evident on their face. If the Insolubilia (Insolubles), Obligationes (Obligations), or De Petitionibus Contrariorum (On Contrary Assumptions) are correctly attributed to William, he also provides one of the earliest discussions of semantic and pragmatic self-referential paradoxes in the Middle Ages.

William was probably born in Nottinghamshire between 1200 and 1205. He studied at Oxford, and was a master there by 1252. Norman Kretzmann and Martin Grabmann claim that he taught at Paris between 1240 and 1248; but L. M. De Rijk argues convincingly that there is no reason to suppose he was ever at Paris, and the chief manuscript for his works is in an English hand. Although later generations took...