Universals

4. Nominalism and Realism

During the Middle Ages in Europe, universals played a focal role in the intellectual economy: many issues revolved around what became known as the problem of universals. Famously, a commentary by Boethius on Porphyry’s Isagoge, which in turn was intended as an introduction to Aristotle’s Categories, set very crisply but vividly and tantalizingly what came to be taken as a compulsory question in the Medieval pursuit of learning: whether genera and species are substances or are set in the mind alone; whether they are corporeal or incorporeal substances; and whether they are separate from the things perceived by the senses or set in them (Boethius c.510; Spade 1994). The initial problem for many was not one of deciding whether there are any universals, but of choosing between Plato and Aristotle and then fine-tuning further details.

Later in the Middle Ages, however, a growing number of philosophers and theologians became more and more impressed by arguments against the existence of universals. They began to adopt the position called ‘Nominalism’ which was opposed to all the various forms of Platonic or Aristotelian Realism. According to Nominalists like Abelard and Ockham, the only thing which distinct individuals share in common is a common name, a label which we choose to apply to each of those individuals and not to others.

Nominalistic claims were echoed by many of the champions of the modern sciences as they emerged at the end of the Middle Ages. It was standardly said to be granted on all hands that all existing things are merely particular. Being assumed as granted on all hands, it was not up for debate, and so the problem of universals, explicitly so described, settled into the shadowy background of scientific and philosophical discussion. For example, an archaeologist of ideas might argue that, in Kant, the problem of universals is really alive and working very hard in the background, playing a role in discussions on almost every topic that arises. Nonetheless the problem of universals, under that name or any clear equivalent, is not featured on Kant’s explicit agenda. Kant speaks of intuitions and concepts in ways which have some relation to the old problem of particulars and universals, but more has shifted than just the labels. Hence the problem of universals has received little attention across a great span of philosophical history, right through to twentieth-century philosophy in France and Germany (see Nominalism §2; Realism and antirealism).