  In the medieval discussion of relations, it is this difference—the difference between reductive and non-reductive realism—that constitutes the greatest divide among philosophers, and representatives of both positions can be found throughout the medieval period. Peter Abelard (d. 1142) and Albert the Great (d. 1280) are, perhaps, the clearest representatives of reductive and non-reductive realism, respectively, in the early and high Middle Ages, whereas William Ockham (d. 1347) and John Duns Scotus (d. 1308) are well-known representatives of these positions in the later Middle Ages.  Again, some philosophers appear to have held different positions at different stages of their career. Henry Harclay (d. 1317), for example, began his career as a staunch defender of Scotus’s non-reductive realism, but by the end of it gravitated towards a position that is much closer to, and in many ways anticipates, Ockham’s specific form of reductive  realism.[17]