The Problem of Universals from Boethius to John of Salisbury

The problem of universals is one of the main philosophical issues. In this book the author reconstructs the history of the problem considering a selection of medieval representative texts and authors. The source of medieval and postmedieval debate is identified in the Socratic-Platonic survey on the definition of concepts. In the Categories, Aristotle discusses important topics concerning the relations that exist between logical terms. In particular he establishes a kind of predication principle: categorial terms have a certain predication relation if (and only if) some facts expressed by ordinary sentences hold. The Categories also because of their particular disciplinary status, halfway between logic and metaphysics, leave a number of questions open. Among these questions, a particularly intriguing one is Porphyry's riddle: are there genera and species? And, if there are such things, what are they like?