also called WILLIAM OCKHAM, Ockham also spelled OCCAM, byname VENERABILIS INCEPTOR (Latin: “Venerable Enterpriser”), or DOCTOR INVINCIBILIS (“Invincible Doctor”), (b. c. 1285, Ockham, Surrey?, Eng. — d. 1347/49, Munich, Bavaria [now in Germany]), Franciscan philosopher, theologian, and political writer, a late scholastic thinker regarded as the founder of a form of nominalism — the school of thought that denies that universal concepts such as “father” have any reality apart from the individual things signified by the universal or general term.

Little is known of Ockham’s childhood. It seems that he was still a youngster when he entered the Franciscan order. At that time a central issue of concern in the order and a main topic of debate in the church was the interpretation of the rule of life composed by St. Francis of Assisi concerning the strictness of the poverty that should be practiced within the order. Ockham’s early schooling in a Franciscan convent concentrated on the study of logic; throughout his career, his interest in logic never waned, because he regarded the science of terms as fundamental and indispensable for practicing all the sciences of things, including God, the world, and ecclesiastical or civil institutions; in all his disputes logic was destined to serve as his chief weapon against adversaries.

After his early training, Ockham took the traditional course of theological studies at the University of Oxford and apparently between 1317 and 1319 lectured on the Sentences of Peter Lombard — a 12th-century theologian whose work was the official textbook of theology in the universities until the 16th century. His lectures were also set down in written commentaries, of which the commentary on Book I of the Sentences (a commentary known as Ordinatio) was actually written by Ockham himself. His opinions aroused strong opposition from members of the theological faculty of Oxford, however, and he left the university without obtaining his master’s degree in theology. Ockham thus remained, academically speaking, an undergraduate — know as an inceptor (“beginner”) in Oxonian language or, to use a Parisian equivalent, a baccalaureus formatus.

Ockham continued his academic career, apparently in English convents, simultaneously studying points of logic in natural philosophy and participating in theological debates. When he left his country for Avignon, Fr., in the autumn of 1324 at the pope's request, he was acquainted with a university environment shaken not only by disputes but also by the challenging of authority: that of the bishops in doctrinal matters and that of the chancellor of the university, John Lutterell, who was dismissed from his post in 1322 at the demand of the teaching staff.

However abstract and impersonal the style of Ockham’s writings may be, they reveal at least two aspects of Ockham’s intellectual and spiritual attitude: he was a theologian-logician (theologicus logicus is Luther’s term). On the one hand, with his passion for logic he insisted on evaluations that are severely rational, on distinctions between the necessary and the incidental and differentiation between evidence and degrees of probability – an insistence that places great trust in man’s natural reason and his human nature. On the other hand, as a theologian he referred to the primary importance of the God of the creed whose omnipotence determines the gratuitous salvation of men; God’s saving action consists of giving without any obligation and is already profusely demonstrated in the creation of nature. The medieval rule of economy, that "plurality should not be assumed without necessity," has come to be known as “Ockham’s razor”; the principle was used by Ockham to eliminate many entities that had been devised, especially by the scholastic philosophers, to explain reality.

Ockham met John Lutterell again at Avignon; in a treatise addressed to Pope John XXII, the former chancellor of Oxford denounced Ockham's teaching on the Sentences, extracting from it 56 propositions that he showed to be in serious error. Lutterell then became a member of a committee of six theologians that produced two successive reports based on extracts from Ockham's commentary, of which the second was more severely critical. Ockham, however, presented to the pope another copy of the Ordinatio in which he had made some corrections. It appeared that he would be condemned for his teaching, but the condemnation never came.

At the convent where he resided in Avignon, Ockham met Bonagratia of Bergamo, a doctor of civil and canon law who was being persecuted for his opposition to John XXII on the problem of Franciscan poverty. On Dec. 1, 1327, the Franciscan general Michael of Cesena arrived in Avignon and stayed at the same convent; he, too, had been summoned by the pope in connection with the dispute over the holding of property. They were at odds over the theoretical problem of whether Christ and his Apostles had owned the goods they used; that is, whether they had renounced all ownership (both private and corporate), the right of property and the right to the use of property. Michael maintained that because Christ and his Apostles had renounced all ownership and all rights to property, the Franciscans were justified in attempting to do the same thing.

The relations between John and Michael grew steadily worse, to such an extent that, on May 26, 1328, Michael fled from Avignon accompanied by Bonagratia and William. Ockham, who was already a witness in an appeal secretly drafted by Michael on April 13, publicly endorsed the appeal in September at Pisa, where the three Franciscans were staying under the protection of Emperor Louis IV the Bavarian, who had been excommunicated in 1324 and proclaimed by John XXII to have forfeited all rights to the empire. They followed him to Munich in 1330, and thereafter Ockham wrote fervently against the papacy in defense of both the strict Franciscan notion of poverty and the empire.

Instructed by his superior general in 1328 to study three papal bulls on poverty, Ockham found that they contained many errors that showed John XXII to be a heretic who had forfeited his mandate by reason of his heresy. His status of pseudo-pope was confirmed in Ockham’s view in 1330-31 by his sermons proposing that the souls of the saved did not enjoy the vision of God immediately after death but only after they were rejoined with the body at the Last Judgment, an opinion that contradicted tradition and was ultimately rejected.

Nevertheless, his principal dispute remained the question of poverty, which he believed was so important for religious perfection that it required the discipline of a theory: whoever chooses to live under the evangelical rule of St. Francis follows in the footsteps of Christ who is God and therefore king of the universe but who appeared as a poor man, renouncing the right of ownership, submitting to the temporal power, and desiring to reign on this earth only through the faith vested in him. This reign expresses itself in the form of a church that is organized but has no infallible authority – either on the part of a pope or a council – and is essentially a community of the faithful that has lasted over the centuries and is sure to last for more, even though temporarily reduced to a few, or even to one; everyone, regardless of status or sex, has to defend in the church the faith that is common to all.

For Ockham the power of the pope is limited by the freedom of Christians that is established by the gospel and the natural law. It is therefore legitimate and in keeping with the gospel to side with the empire against the papacy or to defend, as Ockham did in 1339, the right of the king of England to tax church property. From 1330 to 1338, in the heat of this dispute, Ockham wrote 15 or 16 more or less political works; some of them were written in collaboration, but Opus nonaginta dierum (“Work of 90 Days”), the most voluminous, was written alone.

Excommunicated after his flight from Avignon, Ockham maintained the same basic position after the death of John XXII in 1334, during the reign of Benedict XII (1334-42), and after the election of Clement VI. In these final years he found time to write two treatises on logic, which bear witness to the leading role that he consistently assigned to that discipline, and he discussed the submission procedures proposed to him by Pope Clement. Ockham was long thought to have died at a convent in Munich in 1349 during the Black Death, but he may actually have died there in 1347. (P.D.V.)

Arthur Stephen McGrade, The Political Thought of William of Ockham: Personal and Institutional Principles (1974), focuses on Ockham as a political theorist and activist. Gordon Leff, William of Ockham: The Metamorphosis of Scholastic Discourse (1975), examines his system of thought. Marilyn McCord Adams, William Ockham, 2 vol. (1987), discusses in detail his thinking on a variety of complex topics.