John Buridan on the Doctrine of Aristotle’s Categories

The Categories was generally the first text of Aristotle’s read in the medieval universities. Categories concerns “things that are,” but leaves it to the reader to determine what types of “things” Aristotle has in mind. Generally Categories is interpreted as denying the existence of Plato’s Forms, each an eternally existent, singular, paradigm instance of some natural kind whose members depend on the Form for their existence and nature. Categories purportedly drags these Forms to earth, casting them as inherent, shared natures. Thus there are no Platonic Forms, only particular instances of general natures that have no existence apart from individuals. There is no Form of ‘Humanity’, only individual humans. Medieval philosophers rejected Platonic Forms, though many accepted the supposedly Aristotelian notion of immanent universals, to which they refer Categories’ discussion of, e.g., ‘humanity’. Nominalists, however, deny the existence of any universal (immanent or transcendent) and, with this, any possible knowledge of such universals. Accordingly, they read Categories as a logical work concerning the properties of the terms that we use to speak of individuals and their qualities. Categories’ discussion of ‘humanity’, then, offers knowledge only of the function of an abstract term, and Aristotle’s influential work is brought into line with a nominalist metaphysics. Can this reduction work? If so, can modern scholarship benefit from medieval renderings of this canonical text? Arguably the influential fourteenth-century Parisian arts master John Buridan was his generation’s most sophisticated proponent of nominalism. This paper presents and evaluates his nominalist reading of Aristotle’s text.