The English philosopher and theologian William of Ockham (ca. 1284-1347) was the most important intellectual figure in the 14th century and one of the major figures in the history of philosophy.

The first half of the 14th century was one of the most active, creative periods in medieval thought. Building on the solid foundation of the 13th-century achievements in science, logic, metaphysics, and epistemology, William of Ockham and his immediate followers developed an approach to philosophy and theology that became known as nominalism. This school of thought, alongside the humanist movement, aided in the transition from the medieval to the modern world.

Early Life

William was born in the village of Ockham in Surrey. Having received his early education in Latin grammar and the liberal arts, possibly at the nearby monastic house of Augustinian canons at Newark, he joined the Franciscan order and studied arts and philosophy at their convent in London. In February 1306 he was ordained a subdeacon at the church of St. Saviour at Southwark in London, where Southwark Cathedral now stands. The following fall Ockham began his 13 years of theological study at Oxford.

During the years 1317 to 1320 Ockham lectured on the Sentences of Peter Lombard, the standard theological textbook from the 12th to the 16th centuries. After the completion of his theological studies, he became lecturer at the Franciscan convent in Reading, where he taught off and on until 1324. There he revised the first book of his commentary on the Sentences, lectured on logic and Aristotle's Physics, and engaged in quodlibetic disputes with other theologians.

In these various works Ockham set forth ideas which, within 20 years, earned him an international reputation and placed him alongside Thomas Aquinas and John Duns Scotus as one of the most significant minds of the age. Like Thomas and Scotus, the different areas of Ockham's thought are closely interrelated and marked by distinctive features that give his thought a special character. Ockham's ideas should not, however, be seen as a rejection or destruction of 13th century thought. He borrowed from the past and perfected constructive tendencies already present in the previous period.

Epistemology and Empiricism

The 13th-century tendency to base scientific knowledge, knowledge of the physical world, on sense experience was accepted and extended by Ockham. In place of the Aristotelian description of how man comes to know (a description that sees the human mind primarily as a passive receptacle that abstracts the universal form or concept from particular things that are experienced and transmitted through a multistage process), Ockham described the mind as an active agent that knows the particular immediately and directly through intuitive cognition. Intuitive cognition is the direct apprehension by the mind of a particular, existing thing according to which the mind forms a judgment that such a thing exists and apprehends those facts contingent upon its existence, such as size, shape, color, and so on. In addition to intuitive cognition, which is the initial and primary means of knowledge, there is abstractive cognition, closely related to memory, which can reflect on an object but does not convey any knowledge of whether the object presently exists.

This direct apprehension of the existing particular thing by means of intuitive cognition increased the empirical quality of medieval thought at the expense of the Platonic reliance on forms or ideas. It also meant that man initially and primarily knows the particular, and only on the basis of that and similar experiences does he begin to form a more general concept known as the universal.

It is because of Ockham's rejection of the "realistic" interpretation of the universal or general concept that the term "nominalist" is applied to him. Ockham rejected the idea that there is similarity among things of the same species because there exists a "common nature," prior to existing individual things, which inheres in the latter and makes them similar. While recognizing similarities among things in nature, Ockham saw that similarity as the result of a generic relationship that does not endanger the peculiar individuality of each object. The concept is formed when several individuals of the same species are considered at the same time, and when one forms a composite in the mind of those features they have in common. One of the results of this approach, with its stress on the priority and importance of knowledge of the particular, was to give added impulse to the scientific tradition of the 13th and 14th centuries by stressing both empiricism and an inductive method.

Theology and Ethics

By restricting the objects of scientific knowledge to those individuals known directly through sense experience and by rejecting the idea of a common nature prior to and inherent in the things experienced, Ockham limited the kind of things man could know by reason apart from revelation, and he thus changed the character of metaphysical discussion. In much the same way, Ockham limited the number of truths in theology that can be established by reason alone, thus making theological propositions depend much more on revelation and the teaching of the Church than would be true for earlier scholastic theologians from Anselm to Aquinas. Most "truths" of natural theology are, for Ockham, learned by way of revelation.

Because most theological propositions are known only through revelation, this does not make them any the less certain for Ockham, who saw certainty as the result of different types of evidence. Scientific knowledge produces a certainty based on belief in the way man's mind operates and in the validity of human sense experience. For Ockham this form of knowledge is so compelling that it is impossible not to acknowledge its certainty. The certainty of theological knowledge is based on belief that what God has revealed through Scripture and the Church cannot be in error. Such "knowledge" is compelling only for the Christian and is not of the same order as scientific knowledge.

The overriding conception of Ockham's theology is the freedom and omnipotence of God, an idea that shapes much of his philosophy as well. The realm of God's choice is limited only by the principle of contradiction, namely, that God cannot do that which is logically impossible. Since God wills from eternity and not within time, the choices made by God have become the reliable principles upon which the human world depends. The uniformity in nature which Ockham continually asserted is basically a uniformity in God's will, which can never be arbitrary because it is one with His intellect and wisdom. By His initial choices God has freely bound Himself to act in reliable, definable ways, both within the physical world and within the Church.

The contingency of the universe and the theological order upon the will of God includes the ethical system according to which God rewards and punishes. Good deeds are defined by their conformity to God's revealed law, and although God retains his freedom to reject as meritorious those good deeds done in a state of grace, he has in fact committed himself to accept them as meritorious of eternal life.

Final Years

In 1324 Ockham was called to Avignon to answer charges of heretical doctrine in his writings. Two lists of suspect opinions were drawn up, but neither resulted in a formal condemnation.

While living in Avignon near the papal court awaiting the results of the investigation, Ockham wrote a defense of his theories on the Eucharist, which was one of the major areas of his thought under attack. In addition, at the urging of the head of the Franciscan order, Michael of Cesena, Ockham undertook a study of the concept of apostolic poverty, a concept basic to the Franciscan ideal and one under attack by Pope John XXII. When in 1328, Ockham came to the conclusion that John XXII was incorrect on the issue of apostolic poverty and perhaps even heretical--and when it appeared that the Pope was about to deliver a pronouncement on the issue that would make the Franciscan position appear heretical--Ockham, Cesena, and several others fled Avignon on the night of May 26 toward Italy, and they sought and received the protection of John's major enemy, Emperor Louis of Bavaria.

The remainder of Ockham's life was spent at the Franciscan convent in Munich, where he wrote political treatises against the positions of John XXII and his successors. In these treatises Ockham argued that Scripture and the established theological tradition of the Church are the two sources for authority in doctrine. Neither the papacy nor secular political powers have the authority to proclaim doctrines that go against Scripture or tradition. Ockham agreed with Marsilius of Padua that Christ did not establish the papacy, and one can find in Ockham a strong defense of the authority of a general Church council. However, unlike Marsilius, Ockham believed that the pope did possess administrative authority within the Church, and as long as he did not fall into heresy he should not have his administrative or judicial power questioned.

Further Reading

• The best introduction in English to Ockham's thought is The Collected Articles on Ockham (1958) by Philotheus Böehner, who, more than anyone else, was responsible for the revised understanding of Ockham. Particular aspects of Ockham's thought are examined in Ernest A. Moody, The Logic of William of Ockham (1935); Damascene Webering, The Theory of Demonstration according to William Ockham (1953); and Herman Shapiro, Motion, Time and Place according to William Ockham (1957). For background see Philotheus Böehner, Medieval Logic: An Outline of Its Development from 1250 to c. 1400 (1952); Gordon Leff, Medieval Thought: St. Augustine to Ockham (1958) and Paris and Oxford Universities in the 13th and 14th Centuries (1968); David Knowles, The Evolution of Medieval Thought (1962); and Arthur Hyman and James J. Walsh, eds., Philosophy in the Middle Ages: The Christian, Islamic and Jewish Traditions (1967).
• Adams, Marilyn McCord, William Ockham, Notre Dame, Ind.: University of Notre Dame Press, 1987.