Aristotle's theory of universals
Encyclopedia
Aristotle's theory of universals is one of the classic solutions to the problem of universals
Problem of universals
The problem of universals is an ancient problem in metaphysics about whether universals exist. Universals are general or abstract qualities, characteristics, properties, kinds or relations, such as being male/female, solid/liquid/gas or a certain colour, that can be predicated of individuals or...

. Universals
Universal (metaphysics)
In metaphysics, a universal is what particular things have in common, namely characteristics or qualities. In other words, universals are repeatable or recurrent entities that can be instantiated or exemplified by many particular things. For example, suppose there are two chairs in a room, each of...

 are simply types, properties, or relations that are common to their various instances. In Aristotle's view, universals exist only where they are instantiated
Instantiation
Instantiation or instance*Philosophy:*A modern concept similar to participation in classical Platonism, see the Theory of Forms.*The principle of instantiation, the idea that in order for a property to exist, it must be had by some object or substance.*Universal instantiation and existential...

; they exist only in things (he said they exist in re, which means simply "in things"), never apart from things. Beyond this Aristotle said that a universal is something identical in each of its instances. So all red things are similar in that there is the same universal, redness, in each thing. There is no Platonic form of redness, standing apart from all red things; instead, in each red thing there is the same universal, redness.

To further flesh out Aristotle's theory of universals, it is useful to consider how the theory might satisfy the constraints on theories of universals listed in the problem of universals
Problem of universals
The problem of universals is an ancient problem in metaphysics about whether universals exist. Universals are general or abstract qualities, characteristics, properties, kinds or relations, such as being male/female, solid/liquid/gas or a certain colour, that can be predicated of individuals or...

 article.

First of all, on Aristotle's view, universals can be instantiated multiple times. Aristotle stresses, after all, the one and the same universal, applehood (say), that appears in each apple. Common sense
Common sense
Common sense is defined by Merriam-Webster as, "sound and prudent judgment based on a simple perception of the situation or facts." Thus, "common sense" equates to the knowledge and experience which most people already have, or which the person using the term believes that they do or should have...

 might detect a problem here. (The problem can arise for other forms of realism about universals, however.) Namely, how can we make sense of exactly the same thing being in all of these different objects? That after all is what the theory says; to say that different deserts, the Sahara, the Atacama, and the Gobi are all dry places, is just to say that exactly the same being, the universal dryness, occurs at each place. It seems troubling if we expect universals to be like physical objects, but remember, we are talking about a totally different category of being. So a common defense of realism (and hence of Aristotle's realism) is that we should not expect universals to behave as ordinary physical objects do. Maybe then it is not so strange, then, to say that exactly the same universal, dryness, occurs all over the earth at once; after all, there is nothing strange about saying that different deserts can be dry at the same time.

Are Aristotelian universals abstract? And are they, then, what we conceive of when we conceive of abstract object
Abstract object
An abstract object is an object which does not exist at any particular time or place, but rather exists as a type of thing . In philosophy, an important distinction is whether an object is considered abstract or concrete. Abstract objects are sometimes called abstracta An abstract object is an...

s such as redness? Perhaps.

It will help to explain something about how we form concepts, according to Aristotle. We might think of a little girl just forming the concept of human beings. How does she do it? When we form the concept of a universal on Aristotle's theory, we abstract from a lot of the instances we come across. We as it were mentally extract from each thing the quality that they all have in common. So how does the little girl get the concept of a human being? She learns to ignore the details, tall and short, black and white, long hair and short hair, male and female, etc.; and she pays attention to the thing that they all have in common, namely, humanity. On Aristotle's view, the universal humanity is the same in all humans (i.e., all humans have that exact same type in common); and this allows us to form a concept of humanity that applies to all humans.

Are Aristotelian universals the sorts of things we refer to when we use general terms, like 'redness' and 'humanity'? Again, perhaps. The idea is that when we refer to humanity, we refer to the type, human being, that appears identically in each human. We do not refer simply to all the humans, but instead the type, human being, which is the same in each human.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK