William of Ockham holds the distinction of being the most rejected but influential philosopher-theologian of the fourteenth century. His ideas have been the subject of revisionist assessments ever since that time. In some circles he continues to be a bête noire, in others a harbinger of modern advances in the philosophical analysis of language, nature, and society.

William was born around 1285 in the town of Ockham (probably modern-day Woking) in Surrey. Around the age of twelve he entered the Franciscan friary, probably at London. He would have spent his first year in novitiate, and then he would have undertaken his eight-year study of philosophy. In 1306 he was ordained subdeacon at Southwark, London, in the archdiocese of Winchester. Probably around 1306-1307 he began the study of theology at Oxford. His first six years would have been spent attending lectures on the Bible and the Libri Quatuor Sententiarum...