Substance is an entity found in several metaphysical theories. Such a thing is considered distinct from accidents.


One of Aristotle's categories of being is (translated into English as substance). He distinguishes between what he calls "primary substances" and "secondary substances". Primary substances are defined as what is neither said of a subject nor what is in a subject. Secondary substances are basically Universals, as shown in his own words:

Substance, in the truest and primary and most definite sense of the word, is that which is neither predicable of a subject nor present in a subject; for instance, the individual man or horse. But in a secondary sense, those things are called substances within which, as species, the primary substances are included; also those which, as genera, include the species. For instance, the individual man is included in the species 'man', and the genus to which the species belongs is 'animal'; these, therefore-that is to say, the species 'man' and the genus 'animal,-are termed secondary substances. [1]

See AlsoEdit


  1. Aristotle. Categories. Translated by E. M. Edghill, Massachusetts Institute of Technology. Web. <>