In philosophy the notion of categories derives from Aristotle’s (384-322 B.C.E.) logic and ontology. In logic the categories are understood to be the predicate of a proposition, and in ontology they are the ultimate kinds or modes of all being. In his work the Categories, Aristotle identified ten of these basic modes, namely: substance, quantity, quality, relation, place, time, position, state, action, and passion. Later scholars sometimes suggest that these ten categories can be reduced to the first four: substance, quantity, quality, and relation.


Just as Aristotle proposed that categories are intertwined with ideas of being, cognition, and language, the discussion of central issues in philosophy shifted from having an ontological emphasis to an epistemological and linguistic one. The study of categories is central to each thought since it clarifies its structural characteristics.


Primacy of Substance

For Aristotle the category of substance is most the basic and fundamental one such that all the others are founded upon it. In general a substance is simply any real entity or thing which exists or subsists on its own; that is, a substance possesses its own inner organic principle or structure (essence) such that it makes it the kind of thing that it is. Aristotle arranged these substances into a hierarchy of plants (vegetative souls), animals (sensible souls), and humans (rational souls). Moreover, Aristotle divided the notion of substance into primary and secondary substances. In brief, a primary substance is any actual or particular substance (for example, John Brown, or Fluffy). Secondary substances are the universal categories that are used to classify the primary substances into various species and genera. For instance, John (as primary substance) can be classified as human being, animal, living being, etc., while Fluffy, can be classified as cat, animal, living being, etc. We see here how the ontology of real things is related to logical predication in that we can say, “John is a human being.” or “Fluffy is a cat.” That is, this real or actual being (John) is a specific kind of thing (human being under the category of substance). It is on the basis of these real things or entities (primary substances) that the secondary substances as universals are derived or abstracted. On the other hand, since Aristotle thought that essences were real and eternal there is controversy among scholars regarding the ultimate status of essences and in turn whether the categories are primarily logical or ontological.

Other Categories

On this above foundation, then, we can see how all the other categories are based upon the primacy of substance, both ontologically and logically. First, ontologically the other nine categories are understood to be accidental modes of substances. For example, the fact that John’s hair is brown refers to an accidental feature (quality) of his being human (essence/substance). For even if his hair was blond, he would still be human. Moreover, it takes a number of primary substances (John, Jill, and Jack) to form a quantity (three). Also, John can be related to Fluffy in a certain manner or mode (as her owner, for instance). In this way, then all the other categories are likewise derived from substance. John can be in a particular place (New York City) at a particular time (February 3) and in a particular state (excited, hungry, or annoyed). Furthermore, all logical predication is expressed in a similar fashion. For this reason, we can state the following propositions: “John is in New York.”, “John is excited.”, or “Fluffy is brown.”

List of Aristotle's categories

  • substance
  • quantity
  • quality
  • relation
  • place
  • time
  • position
  • state
  • action
  • passion


In modern philosophy the notion of categories is most often associated with Immanuel Kant (1724-1804). For Kant the categories refer to the forms or principles of understanding, which constitute the necessary conditions of all experience. While denying the right to make metaphysical judgments regarding real things or substances, Kant attempted to map out the limits of reason which are determined by the basic categories of our understanding. He divided these categories into four basic classes with three sub-classes in each, thus making twelve categories altogether. They are:

  • Quantity
    • unity
    • plurality
    • totality
  • Quality
    • reality
    • negation
    • limitation
  • Relation
    • inherence/subsistence
    • causality/dependence
    • community
  • Modality
    • possibility
    • existence
    • necessity

After Kant

Since categories are fundamental to the structure of thought, each philosophy approaches it from a unique perspective. Hegel, Neo-Kantians, Nicholai Hartmann, and Dilthey all had different ideas on which categories are fundamental and the meaning of each category. After the late nineteenth century, beginning with Frege and Russell, linguistic categories took precedence over other concerns.


  • Brentano, Franz Clemens, and Rolf George. On the Several Senses of Being in Aristotle. Berkeley: University of California Press, 1975. ISBN 0520023463
  • Brentano, Franz Clemens. The Theory of Categories. Melbourne international philosophy series, v. 8. The Hague: Martinus Nijhoff, 1981. ISBN 9024723027
  • Gorman, Michael, and Jonathan J. Sanford. Categories: Historical and Systematic Essays. Studies in philosophy and the history of philosophy, v. 41. Washington, D.C.: Catholic University of America Press, 2004. ISBN 0813213770
  • Grossmann, Reinhardt. The Categorial Structure of the World. Bloomington: Indiana University Press, 1983. ISBN 0253313244
  • Körner, Stephan. Categorial Frameworks. Library of philosophy and logic. Oxford: Blackwell, 1970. ISBN 0631136002
  • Mann, Wolfgang-Rainer. The Discovery of Things: Aristotle's Categories and Their Context. Princeton, N.J.: Princeton University Press, 2000. ISBN 069101020X
  • Westerhoff, Jan. Ontological Categories: Their Nature and Significance. Oxford, UK: Oxford University Press, 2005. ISBN 0199285047

External Links

All links retrieved January 18, 2017.

  • Categories Stanford Encyclopedia of Philosophy.
  • Aristotle. Categories translated by E. M. Edghill.

General Philosophy Sources


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