Categories
This short treatise distinguishes ways of saying what something is: substance, quantity, quality, relation and the remaining categories. Ordinary examples introduce a difficult question: is the inquiry about words, their meanings or the things themselves?
Understanding the text
Traditionally the opening work of the Organon, it shaped centuries of commentary on universals and predication.
Key points
- 01
Primary substance
An individual, such as this person or this horse, supports properties without itself being predicated of an underlying subject.
- 02
Said of and present in
Being said of a subject differs from being present in a subject; grammatical examples alone cannot explain the resulting classification.
- 03
Relations
A relation refers beyond itself to something else, complicating an ontology organized around independent substances.
Explore the ideas in depth
Said of and present in a subject
The treatise distinguishes what is said of a subject, such as a species predicated of an individual, from what is in a subject, such as a quality present in a body. These distinctions help explain how things are classified and propositions formed without simply identifying words with objects.
Substance and the other categories
An individual person or horse illustrates primary substance; quantity, quality, relation and other categories indicate different ways of characterizing something. Follow the text’s examples and ask whether each classification remains useful in other sciences or languages.
How to read it
Begin with chapters 1–5 and construct examples before comparing the ten categories.
Editions & sources
- Consult the reference 1classics.mit.edunew tab
- Consult the reference 2plato.stanford.edunew tab
- Consult the reference 3classics.mit.edunew tab
Summaries and key points are original editorial interpretations. They accompany reading the work and do not replace an edition of the text. Editorial method ↗