The Medieval Problem of Universals First published Sun Sep 10, 2000; substantive revision Tue Oct 31, 2017 “The problem of universals” in general is a historically variable bundle of several closely related, yet in different conceptual frameworks rather differently articulated metaphysical, logical, and epistemological questions, ultimately all connected to the issue of how universal cognition of singular things is possible. How do we know, for example, that the Pythagorean theorem holds universally, for all possible right triangles? Indeed, how can we have any awareness of a potential infinity of all possible right triangles, given that we could only see a finite number of actual ones? How can we universally indicate all possible right triangles with the phrase ‘right triangle’? Is there something common to them all signified by this phrase? If so, what is it, and how is it related to the particular right triangles? The medieval problem of universals is a logical, and historical, continuation of the ancient problem generated by Plato’s (428–348 B.C.) theory answering such a bundle of questions, namely, his theory of Ideas or Forms. 1. Introduction 2. The Emergence of the Problem 3. The Origin of the Specifically Medieval Problem of Universals 4. Boethius’ Aristotelian Solution 5. Platonic Forms as Divine Ideas Divine Ideas and Divine Simplicity Illuminationism vs. Abstractionism 6. Universals According to Abelard’s Aristotelian Conception 7. Universal Natures in Singular Beings and in Singular Minds 8. Universals in the Via Antiqua 9. Universals in the Via Moderna 10. The Separation of the Viae, and the Breakdown of Scholastic Discourse in Late-Medieval Philosophy Bibliography Primary Literature Secondary Literature Academic Tools Other Internet Resources Related Entries 1. Introduction The inherent problems with Plato’s original theory were recognized already by Plato himself. In his Parmenides Plato famously raised a number of difficulties, for which he apparently did not provide satisfactory answers. Aristotle (384–322 B.C.), with all due reverence to his teacher, consistently rejected Plato’s theory, and heavily criticized it throughout his own work