William of Ockham (also Occam or any of several other spellings) (ca. 1285 – 1349) was a English Franciscan friar and philosopher, from Ockham, a small village in Surrey, near East Horsley. William was devoted to a life of extreme poverty and minimalism. A pioneer of nominalism, some consider him the father of modern epistemology and modern philosophy in general, because of his strongly argued position that only individuals exist, rather than supra-individual universals, essences, or forms, and that universals are the products of abstraction from individuals by the human mind and have no extra-mental existence. Ockham is also considered one of the greatest logicians of all time.
Dave Beckett of the University of Kent at Canterbury wrote:
"The medieval rule of parsimony, or principle of economy, frequently used by Ockham came to be known as Ockham's razor."
Summoned to Avignon in 1324 by Pope John XXII on accusation of heresy, William spent four years there in effect under house arrest while his teaching and writing were being investigated. During this period, at the request of Brother Michael of Cesena, head of the Franciscan order, Ockham investigated the controversy between the Franciscans and the Papacy on the doctrine of apostolic poverty, which was central to Franciscan doctrine but anathema to the Pope. Ockham concluded that Pope John XXII was a heretic, a position that he later put forth in writing. Before a conclusion was reached about the heresy or orthodoxy of William's philosophy, he fled Avignon on May 26, 1328 with Michael of Cesena and a few other friars. They sought the protection of Emperor Louis IV in Bavaria. After criticizing the pope, he is believed to have been excommunicated, although historical sources vary. Ockham spent much of the remainder of his life writing about political issues, including the relative authority and rights of the spiritual and temporal powers.
He died in a convent in Munich, Bavaria (now Germany).