Aristotle\'s Theory of Categories

Aristotle Categories

Aristotle's theory of categories provides a fundamental way of explaining the known universe. There are ten different categories, according to Aristotle. These ten categories explain the nature of physical existence. The first category is substance, which is the most fundamental and important category. Substance refers to what a thing is on the elemental level. Aristotle divides this category further into substances such as living vs. nonliving things; and human beings vs. animals. Basically, substance refers to the identity of the object.

The second of the ten categories is quantity, which is a relatively straightforward category based on numbers. Thus, this category refers to anything that is measurable, such as length or number or time. The third category is the quality of the object, which generally refers to its physical qualities and observable features. So far with the three categories, there can be three blue birds (quantity, quality, and substance, in that particular order).

The fourth of the ten categories is the relationship of the object to other objects. Using the same example as above, a yellow bird sits to the right of the three blue birds. The three blue birds are to the left of the yellow bird. Objects can be described in terms of their relationship spatially to other objects. Moreover, objects can be described in terms of their relationship to more abstract concepts.

Fifth is the category of location. The birds are in a tree, and the tree is in Miami. The physical location of an object is important to understand that object. Location can be specific or general. Time is the sixth category, which locates the object in time. Yesterday, the birds were in the tree but now they are not. The seventh category is related to the position of the object. Thus, the birds are sitting in the tree or the birds are standing on the branch.

Possession is the eighth category, which is a more sophisticated dimension that connotes the relationship of one object to another in terms of possession. With the bird example, the bird has a worm in its mouth, or is flying to the tree with a string of hay to build a nest. Alternatively, it could be said that the tree possesses several families of bird residents. Possession is an important categorization precisely because it can define relationships and functions of objects.

The act of doing something is the ninth category for Aristotle. Therefore, flying and chirping are acts that the blue birds might do in the course of any given day or during their lifetimes. Finally, an object can assume a passive role in its relationship to the universe. The tenth category is what is being done to the object. Receiving an action or being receptive or the object of action is an important category or quality of being. In this example, the eagle is attacking the blue birds, or the blue birds are being looked at by bird watchers.