Peter Abelard (1079-1142) was the preeminent philosopher of the twelfth century and perhaps the greatest logician of the middle ages. During his life he was equally famous as a poet and a composer, and might also have ranked as the preeminent theologian of his day had his ideas earned more converts and less condemnation. In all areas Abelard was brilliant, innovative, and controversial. He was a genius. He knew it, and made no apologies. His vast knowledge, wit, charm, and even arrogance drew a generation of Europe’s finest minds to Paris to learn from him.
Philosophically, Abelard is best known as the father of nominalism. For contemporary philosophers, nominalism is most closely associated with the problem of universals but is actually a much broader metaphysical system. Abelard formulated what is now recognized as a central nominalist tenet: only particulars exist. However, his solution to the problem of universals is a semantic account of the meaning and proper use of universal words. It is from Abelard’s claim that only words (nomen) are universal that nominalism gets its name.
Abelard would have considered himself first a logician and then later in his life a theologian and ethicist. He may well have been the best logician produced in the Middle Ages. Several innovations and theories that are conventionally thought to have originated centuries later can be found in his works. Among these are a theory of direct reference for nouns, an account of purely formal validity, and a theory of propositional content once thought to have originated with Gottlob Frege. In ethics Abelard develops a theory of moral responsibility based on the agent’s intentions. Moral goodness is defined as intending to show love of God and neighbor and being correct in that intention.