William of Ockham
From The Art and Popular Culture Encyclopedia
"Peter Lombard invariably confounds the words "substance" and "essence". Ockham says that an "universal" cannot be "substance," as otherwise the idea of individuality belonging to the latter would be destroyed, and Christ would have something in common with the damned. This distinction of the law in God's mind, from the law in nature (the "in naturâ naturante idia," and "in naturâ naturante lex," of Bacon), belongs to Ockham and his school ; but his language shows the accepted meaning of the word substance."--The Early and Middle Ages of England (1861) by Charles Henry Pearson
William of Ockham (also Occam, Hockham, or any of several other spellings, (c. 1288 - c. 1348) was an English Franciscan friar and scholastic philosopher, from Ockham, a small village in Surrey, near East Horsley. He is considered — along with Thomas Aquinas, Duns Scotus, and the Islamic scholar Averroes — to be one of the major figures of medieval thought and was at the centre of the major intellectual and political controversies of the fourteenth century. Although commonly known for Occam's razor, the methodological principle that bears his name, William of Ockham also produced significant works on logic, physics, and theology. In the Church of England, his day of commemoration is 10 April.
William of Ockham was a pioneer of nominalism, and some consider him the father of modern epistemology, because of his strongly argued position that only individuals exist, rather than supra-individual universals, essences, or forms, and that universals are the products of abstraction from individuals by the human mind and have no extra-mental existence. He denied the real existence of metaphysical universals and advocated the reduction of ontology. William of Ockham is sometimes considered an advocate of conceptualism rather than nominalism, for whereas nominalists held that universals were merely names, i.e. words rather than existing realities, conceptualists held that they were mental concepts, i.e. the names were names of concepts, which do exist, although only in the mind. Therefore, the universal concept has for its object, not a reality existing in the world outside us, but an internal representation which is a product of the understanding itself and which "supposes" in the mind the things to which the mind attributes it; that is, it holds, for the time being, the place of the things which it represents. It is the term of the reflective act of the mind. Hence the universal is not a mere word, as Roscelin taught, nor a sermo, as Peter Abelard held, namely the word as used in the sentence, but the mental substitute for real things, and the term of the reflective process. For this reason William has sometimes also been called a "terminist", to distinguish him from a nominalist or a conceptualist.
William of Ockham was a theological voluntarist who believed that if God had wanted to, he could have become incarnate as a donkey or an ox, or even as both a donkey and a man at the same time. He was criticized for this belief by his fellow theologians and philosophers.