Living Post: Notes on Aristotle's Categories

This post contains my notes on The Categories by Aristotle, the first book of The Organon. It will be updated as I make more notes.

Notes on Chapters 1-4

"A Subject"

Any individual instance... Socrates, Callias, Secretariat. This Macbook Pro.

"(present) in a subject"


Aristotle describes something (say, X) as being in a subject as which I am taking to mean "the subject has X as a characteristic". He doesn't mean a member of a collection.

Quote - from Chapter 2 (Ackrill)

(By 'in a subject' I mean what is in something, not as a part, and cannot exist separately from what it is in.) For example, the individual knowledge-of-grammar is in a subject, the soul, but is not said of any subject...


  • indidual knowledge-of-grammar is in a soul
  • white is in a subject, the body
  • all color is in a body

"said of a subject"


When Aristotle says that "X is said of Y", X is an abstraction of individual instances of Y. For instance, man is said of Callias and Socrates. Animal is said of man, cats, dogs, birds.

For something, X, to be said of somethings Y, it means that there is some kind of essential commonality that is being stressed and generalized by X.

Quote - from Chapter 2 (Ackrill) is said of a subject, the individual man...

...knowledge said of a subject, knowledge-of-grammar


(see above.)

Four combinations of "said of" and "in a subject"

These capture some relationship of things/concepts to one another.

    Said of a subject but NOT Present in a subject 
NOT Said of a subject but     Present in a subject 
    Said of a subject and     Present in a subject 
NOT Said of a subject and NOT Present in a subject

Standford refers to this as the four-fold division and says the following:

Aristotle's first system of classification is of beings, (τὰ ὄντα) (1a20). The division proceeds by way of two concepts: (1) said-of and (2) present-in. Any being, according to Aristotle, is either said-of another or is not said-of another. Likewise, any being is either present-in another or is not present-in another. (2)

...By focusing on Aristotle's illustrations, most scholars conclude that beings that are said-of others are universals, while those that are not said-of others are particulars. Beings that are present-in others are accidental, while those that are not present-in others are non-accidental. Now, non-accidental beings that are universals are most naturally described as essential, while non-accidental beings that are particulars are best described simply as non-accidental. If we put these possibilities together, we arrive at the following four-fold system of classification: (1) accidental universals; (2) essential universals; (3) accidental particulars; (4) non-accidental particulars, or what Aristotle calls primary substances. (2)

Said of, but NOT Present-in

What Stanford calls "Essential Universals" (2)

NOT Said of, but Present-in

What Stanford calls "Accidental Particulars" (2)

Said of, and Present-in

What Stanford calls "Accidental Universals" (2)

NOT Said of, and NOT Present-in

Individual beings. What Aristotle elsewhere calls "primary substances".