William of Ockham was born in approximately 1285 in Surrey, England. He studied and taught theology at Oxford University from approximately 1309 to 1319. His opinions brought him in opposition to Pope John XXII, who denounced him for dangerous teaching, and placed him under house arrest in France. In 1328, Ockham escaped to Munich, Bavaria (now Germany) to seek the protection of Louis IV, the Holy Roman emperor. He was subsequently excommunicated by the pope.
Ockham is best known for his rigorous use of logic, which he applied even to religious questions (in part, the reason for his political problems). In particular, he is famous for his principle of logical economy (now known as Ockham's razor in his honor) which states that entities are not to be multiplied without necessity
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William of Ockham died in approximately 1349, probably of the plague.