William of Ockham, the most influential philosopher of the fourteenth century, apparently was born sometime between 1280 and 1290 at the village of Ockham, in Surrey, near London. Entering the Franciscan order at an early age, he commenced his course of theological study at Oxford in 1309 or 1310, and completed the requirements for the degree of master of theology with the delivery of his lectures on Peter Lombard's Book of Sentences in 1318–1319, or, at the latest, 1319–1320. Although an old tradition indicated that he studied under John Duns Scotus, it seems unlikely that he did so, since Duns Scotus left Oxford at the beginning of the century and died in 1308. Ockham's writings show intimate familiarity with the teachings of Duns Scotus, but this is explained by the dominant position Duns Scotus had acquired at Oxford, particularly within the Franciscan order.

Ockham's lectures on the...