William of Ockham

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Born: 1288 in Ockham (near Ripley, Surrey), England
Died: 9 April 1348 in Munich, Bavaria (now Germany)

William of Ockham's early Franciscan education concentrated on logic. He studied theology at Oxford and between 1317 and 1319 he lectured on the Sentences, the standard theology text used in universities up to 16 C.

His opinions aroused strong oposition and he left Oxford without his Master's Degree. He continued studying mathematical logic and made important contributions to it. He considered a three valued logic where propositions can take one of three truth values. This became important for mathematics in the 20th Century but it is remarkable that it was first studied by Ockham 600 years earlier.

Ockham went to France and was denounced by the Pope. He was excommunicated and in 1328 he fled seeking the protection of Louis IV in Bavaria (Louis had also been excommunicated!). He continued to attack papal power always employing logical reasoning in his arguments.