William of Ockham (c.1287–1347)
Authors: Panaccio Claude 
Published: September 2018

William of Ockham is a major figure in late medieval thought. Many of his ideas were actively – sometimes passionately – discussed in universities all across Europe from the 1320s up to the sixteenth century and even later. Against the background of the extraordinarily creative English intellectual milieu of the early fourteenth century, in which new varieties of logical, mathematical and physical speculation were being explored, Ockham stands out as the main initiator of late scholastic nominalism, a current of thought further exemplified – with important variants – by a host of authors after him, from Adam Wodeham, John Buridan and Albert of Saxony to the school of John Mair far into the sixteenth century.

As a Franciscan friar, Ockham taught theology and Aristotelian logic and physics from approximately 1317 to 1324, probably in Oxford and London. He managed to develop in this short period an original and impressive theological and philosophical system. However, his academic career was interrupted by a summons to the Papal Court at Avignon for theological scrutiny of his teachings. Once there, he became involved in the raging quarrel between Pope John XXII and the Minister General of the Franciscan Order, Michael of Cesena, over the poverty of the church. Ockham was eventually excommunicated in 1328. Having fled to Munich, where he put himself under the protection of the Emperor Ludwig of Bavaria, he fiercely continued the antipapal struggle, devoting the rest of his life to the writing of polemical and politically-oriented treatises.

Because he never was officially awarded the title of Doctor in Theology, Ockham has been traditionally known as the venerabilis inceptor, the ‘venerable beginner’, a nickname which at the same time draws attention to the seminal character of his thought. As a tribute to the rigour and strength of his arguments, he has also been called the ‘Invincible Doctor’.

The core of his thought lies in his qualified approach to the old problem of universals, inherited by the Christian world from the Greeks through Porphyry and Boethius. Ockham’s stand is that only individuals exist, generality being but a matter of signification. This is what we call his nominalism. In the mature version of his theory, species and genera are identified with certain mental qualities called concepts or intentions of the mind. Ontologically, these are individuals too, like everything else: each individual mind has its own individual concepts. Their peculiarity, for Ockham, lies in their representative function: a general concept naturally signifies many different individuals. The concept ‘horse’, for instance, naturally signifies all singular horses and the concept ‘white’ all singular white things. They are not arbitrary or illusory for all that: specific and generic concepts, Ockham thought, are the results of purely natural processes safely grounded in the intuitive acquaintance of individual minds with real singular objects; and these concepts do cut the world at its joints. The upshot of Ockham’s doctrine of universals is that it purports to validate science as objective knowledge of necessary connections, without postulating mysterious universal entities ‘out there’.

Thought, in this approach, is treated as a mental language. Not only is it composed of signs, but these mental signs, natural as they are, are also said to combine with each other into propositions, true or false, just as extra-mental linguistic signs do; and in so doing, to follow rules of construction very similar to those of spoken languages. Ockham thus endowed mental discourse with grammatical categories. However, his main innovation in this respect is that he also adapted and transposed to the fine-grained analysis of mental language a relatively new theoretical apparatus that had been emerging in Europe since the twelfth century: the theory of the ‘properties of terms’ – the most important part of the logica modernorum, the ‘logic of the moderns’ – which was originally intended for the semantical analysis of spoken languages. Ockham, in effect (along with some of his contemporaries, such as Walter Burley) promoted this new brand of semantical analysis to the rank of philosophical method par excellence. In a wide variety of philosophical and theological discussions, he made sustained use of the technical notions of ‘signification’, ‘connotation’ and, above all, ‘supposition’ (or reference) and all their cognates. His distinctive contribution to physics, for example, consists mainly in semantical analyses of problematic terms such as ‘void’, ‘space’ or ‘time’, in order to show how, in the end, they refer to nothing but singular substances and qualities.

Ockham’s rejection of universals also had a theological aspect: universals, if they existed, would unduly limit God’s omnipotence. On the other hand, he was convinced that pure philosophical reasoning suffices anyway for decisively refuting realism regarding universals, since all its variants turn out to be ultimately self-contradictory, as he endeavoured to show by detailed criticism.

On the whole, Ockham traced a sharper dividing line than most Christian scholastics before him between theological speculation based on revealed premises and natural sciences in the Aristotelian sense, which are based on empirical evidence and self-evident principles. He wanted to maintain this clear-cut distinction in principle through all theoretical and practical knowledge, including ethics and political reasoning. In this last field, in particular, to which Ockham devoted thousands of pages in the last decades of his life, he strenuously defended the independence of secular power from ecclesiastical power, stressing whenever he could the autonomy of right reason in human affairs.