William of Ockham

William of Ockham (c. 1287–1347) was an English Franciscan friar, philosopher, and theologian whose work reshaped medieval scholasticism and laid intellectual foundations for early modern thought. He is best known for the methodological principle later called "Ockham's Razor" — that explanations should not multiply entities beyond necessity — and for his thoroughgoing nominalism, which denied that universal concepts have any real existence outside the mind. His voluntarist theology stressed the absolute freedom of God's will over any constraining rational order, and his later political writings defended Franciscan poverty and attacked papal temporal power with remarkable force. Under investigation at the papal court in Avignon over his Sentences commentary and the Franciscan poverty dispute, Ockham fled in 1328 before any formal verdict and was excommunicated for leaving without permission; he spent the rest of his life under the protection of Holy Roman Emperor Louis IV in Munich, producing a stream of polemical works on church and state. His epistemology and critique of realism influenced late medieval nominalism, the via moderna, and — through that current — figures of the Protestant Reformation such as Luther.