Roscelin de Compiègne (c.1050–c.1125), French philosopher and logician who became embroiled in theological controversy when he applied his logical teachings to the doctrine of the Trinity. Since almost nothing survives of his written work, we must rely on hostile accounts of his views by Anselm of Canterbury and Peter Abelard, both of whom openly opposed his positions. Perhaps the most notorious view Roscelin is said to have held is that universals are merely the puffs of air produced when a word is pronounced. On this point he opposed views current among many theologians that a universal has an existence independent of language, and somehow is what many different particulars are. Roscelin’s aversion to any proposal that different things can be some one thing is probably what led him in his thinking about the three persons of God to a position that sounded suspiciously like the heresy of tritheism. Roscelin also evidently held that the qualities of things are not entities distinct from the subjects that possess them. This indicates that Roscelin probably denied that terms in the Aristotelian categories other than substance signified anything distinct from substances. Abelard, the foremost logician of the twelfth century, studied under Roscelin around 1095 and was undoubtedly influenced by him on the question of universals. Roscelin’s view that universals are linguistic entities remained an important option in medieval thought. Otherwise his positions do not appear to have had much currency in the ensuing decades. See also ABSTRACT ENTITY, METAPHYSIC. M.M.T.