Page "Problem of universals" Paragraph 21

Nominalism was first formulated as a philosophical theory in the Middle Ages.

The French philosopher and theologian Roscellinus ( c. 1050-c. 1125 ) was an early, prominent proponent of this view.

It can be found in the work of Peter Abelard and reached its flowering in William of Ockham, who was the most influential and thorough nominalist.

Abelard's and Ockham's version of nominalism is sometimes called conceptualism, which presents itself as a middle way between nominalism and realism, asserting that there is something in common among like individuals, but that it is a concept in the mind, rather than a real entity existing independently of the mind.

Ockham argued that only individuals existed and that universals were only mental ways of referring to sets of individuals.

" I maintain ", he wrote, " that a universal is not something real that exists in a subject ... but that it has a being only as a thought-object in the mind in anima ".

As a general rule, Ockham argued against assuming any entities that were not necessary for explanations.

Accordingly, he wrote, there is no reason to believe that there is an entity called " humanity " that resides inside, say, Socrates, and nothing further is explained by making this claim.

This is in accord with the analytical method which has since come to be called Ockham's razor, the principle that the explanation of any phenomenon should make as few assumptions as possible.