Aristotle’s Categories: Four-fold Division of Being

In the previous chapter of the Categories we have already discussed homonymy, synonomy, and paronymy.  This section, Chapter 2 of Aristotle’s Categories, sets forth a four-fold system of classification for “things that are,” [1] in addition to introducing a distinction between things that are said “in combination” and things said “without combination.”  Although not without straying interpretations, the distinction between “combined and uncombined” is rather clear, on my view, from the context.  So I will instead be focusing on the four-fold division that takes up the majority of the chapter and the lion’s share of the philosophical difficulty.  Needless to say, however, for the purpose of an explanatory post such as this, I will be sticking to orthodox and traditional interpretations, although of course there are always divergences and minority reports.

Things That Are Said:


Of the things that are said, some are said in combination (symploke), while some are said without combination.  Those that are said in combination are such as “human runs,” “human wins.”  Those without combination are such as “man,” “ox,” “runs,” “wins.”


Things That Are:


A) Of things that are, some are said of an individual subject (tis hypokeimenon), but are not in any subject, such as “human” is said of an individual human, but is not in any subject.


B) But some are in a subject, yet are said of no subject.  And by “in a subject,” I mean that which exists in something not as a part and is impossible to be apart from that in which it is.  For example, an individual grammatical knowledge (tis grammatike) is in a subject, but is said of no subject, and individual white is in a subject, i.e. a physical body (for every color is in a body) but it is said of no subject.


C) Some are said both of a subject and are in a subject, for example knowledge (episteme) is in a subject, i.e. a soul, but is said of a subject, i.e. grammatical knowledge


D) Some are neither in a subject nor said of a subject, for example, an individual person or an individual horse–– for none of these is in a subject nor is it said of a subject.  And generally, things that are irreducible and one in number are said of no subject, but nothing hinders some things from being in the subject.  For, of the things in a subject, the individual grammatical knowledge is one of them (Aristotle, Categories, 1a16-1b9). [2]

First let us discuss what Aristotle means by “in a subject” and “said of a subject.” Since the four-fold division consists entirely in affirming or denying these classifications, resulting in four distinctions, if we understand these two phrases, we are well on our way to understanding all of this chapter.

The In-a-subject Relation

It is best to understand both the in-a-subject and said-of-a-subject distinctions, at a general level, as belonging to relations between things.  So in-a-subject means that if X is in Y, where Y is the subject, we are to understand Y as either a substance proper or, more abstactly, as that thing, whatever it is, which undergoes the process which results in some relation.  X here cannot exist independently from some kind of subject or substance, and that is why it is said to be “in” a subject, for it will not exist “out” of a subject.  Thus the category of things not a subject or substance, here represented by X, are dependent on the subject for their existence.  So in Aristotle’s example, an individual’s grammar-knowledge (his understanding of how language works) is “in” an individual (his mind) because it is dependent on the individual and cannot exist apart from this individual, viz., Grammatical knowledge is in the mind.

The Said-of-a-subject Relation

While the in-a-subject distinction concerns a subject or substance and its independent status (in contrast to the dependent relation of a non-subject or non-substance), the said-of-a-subject relation pertains to an individual and a universal, or in slightly different wording, to an individual and a species or genus.  Returning to one of Aristotle’s examples, the term human (as a species) is “said of” an individual human, viz., Socrates is a human.

The Four-fold Division Simplified

Now that we have discussed the in-a-subject relation and the said-of-a-subject relation, we can apply these distinctions to the text above to get four categories into which (presumably) all things fit.

A) Essential Universals: Universals (or species and genera) in their relation to substances. E.g. “Human” in “Socrates is human.”
B) Accidental Particulars: Particulars, but not substances. E.g. An individual grammatical knowledge in a person.
C) Accidental Universals: Universals (or species and genera) in their relation to things other than substances. E.g. Knowledge is said both of grammatical knowledge (i.e. grammatical knowledge is knowledge) and is in a subject, i.e. a mind.
D) Primary Substances: Particulars that are substances. E.g. An individual such as Socrates or a particular horse, e.g. Secretariat




[1] Although the division is four-fold, there are actually 6 possibilities; however two of these possibilities are contradictions: “in a subject and not in a subject” and “of a subject and not in a subject.”

[2] Τῶν λεγομένων τὰ μὲν κατὰ συμπλοκὴν λέγεται, τὰ
δὲ ἄνευ συμπλοκῆς. τὰ μὲν οὖν κατὰ συμπλοκήν, οἷον
ἄνθρωπος τρέχει, ἄνθρωπος νικᾷ· τὰ δὲ ἄνευ συμπλοκῆς,
οἷον ἄνθρωπος, βοῦς, τρέχει, νικᾷ.
Τῶν ὄντων τὰ μὲν καθ’ ὑποκειμένου τινὸς λέγεται, ἐν  (20)
ὑποκειμένῳ δὲ οὐδενί ἐστιν, οἷον ἄνθρωπος καθ’ ὑποκειμένου
μὲν λέγεται τοῦ τινὸς ἀνθρώπου, ἐν ὑποκειμένῳ δὲ οὐδενί ἐστιν·
τὰ δὲ ἐν ὑποκειμένῳ μέν ἐστι, καθ’ ὑποκειμένου δὲ οὐδενὸς
λέγεται, —ἐν ὑποκειμένῳ δὲ λέγω ὃ ἔν τινι μὴ ὡς μέρος
ὑπάρχον ἀδύνατον χωρὶς εἶναι τοῦ ἐν ᾧ ἐστίν,— οἷον ἡ τὶς (25)
γραμματικὴ ἐν ὑποκειμένῳ μέν ἐστι τῇ ψυχῇ, καθ’ ὑπο-
κειμένου δὲ οὐδενὸς λέγεται, καὶ τὸ τὶ λευκὸν ἐν ὑποκειμένῳ
μέν ἐστι τῷ σώματι, —ἅπαν γὰρ χρῶμα ἐν σώματι,— καθ’
ὑποκειμένου δὲ οὐδενὸς λέγεται· τὰ δὲ καθ’ ὑποκειμένου τε
(1b.) λέγεται καὶ ἐν ὑποκειμένῳ ἐστίν, οἷον ἡ ἐπιστήμη ἐν ὑπο-
κειμένῳ μέν ἐστι τῇ ψυχῇ, καθ’ ὑποκειμένου δὲ λέγεται
τῆς γραμματικῆς· τὰ δὲ οὔτε ἐν ὑποκειμένῳ ἐστὶν οὔτε καθ’
ὑποκειμένου λέγεται, οἷον ὁ τὶς ἄνθρωπος ἢ ὁ τὶς ἵπ-
πος, —οὐδὲν γὰρ τῶν τοιούτων οὔτε ἐν ὑποκειμένῳ ἐστὶν (5)
οὔτε καθ’ ὑποκειμένου λέγεται·— ἁπλῶς δὲ τὰ ἄτομα καὶ ἓν
ἀριθμῷ κατ’ οὐδενὸς ὑποκειμένου λέγεται, ἐν ὑποκειμένῳ δὲ
ἔνια οὐδὲν κωλύει εἶναι· ἡ γὰρ τὶς γραμματικὴ τῶν ἐν ὑπο-
κειμένῳ ἐστίν.

Aristotle’s Categories, Chapter 1

Famous Passages is an ongoing series explaining notable or influential passages in ancient philosophy.

Aristotle’s Categories is often the first of his works that one should study.  It lays the groundwork for all the philosophizing to follow, and it begins with analysis at its most basic: things and the words we attach to things.

Aristotle introduces three important terms in Categories 1a.

1. The first is what is often more helpfully translated equivocal, but literally in the Greek is homonymous.  This term designates those things which share only a name in common, yet the definition or essence of each thing differs.  The example which Aristotle uses for equivocal terms is a little confusing, since, as can be expected when dealing with ambiguities in language, the Greek does not translate nicely into English.  In Greek the word zoon (ζῷον) can mean either “animal” (it usually means this and this word is where we get English zoo, zoology, etc) or it can also mean “painting.”  Perhaps the meaning “painting” derived from the original meaning of “animal” because animals (including humans) were predominately the subject of paintings.  His example then, is that both a man and the Mona Lisa are both zoon, where in the first instance an animal is intended and in the latter a painting.

2. The second is often termed, in consistency of use with the first term, univocal, though in Greek it is synonomous.  When talking of two things which are univocal, in the Aristotelian sense, we are saying that they share the same name and same definition.  This is not saying something very obvious and simplistic however, such as “table” is the same as “table.”  What Aristotle is driving at here is that a man and an ox are both “animal.”  What does this mean?  That man and an ox are both “animal” in that a) they both can be called “animal” b) they both share the same definition.  This latter part might seem surprising; after all, man and ox are two different types of animals.  But what Aristotle intends here is that the definition of animal, viz. a living creature with metabolism, etc. equally and properly applies to both man and ox.

3. The last term is not of a same piece with the first two.  In Greek the word used is paronymous, although the term derivative is much clearer.  These are those things which can gain their name from something else yet can differ in their endings.  Aristotle gives as his examples “grammarian” as deriving from “grammar” and “bravery” deriving from “brave.”  But this is no mere linguistic point nor Aristotle wishing to point out the dependence of some words on others.  As J.A. Ackrill brings up in his translation, we should be aware that grammar and grammarian both deal with the domain or genus of grammar, but we express this linguistically by saying grammar and grammarian, while understanding that a grammarian is one who deals in grammar.  As he puts it, “If we wish to ascribe generosity to Callias we do not say that he is generosity, but that he is generous” (Ackrill, Aristotle’s Categories and De Interpretatione, 1963, p. 72).


Aristotle’s Essence: τὸ τί ἦν εἶναι

τὸ τί ἦν εἶναι is an odd phrase, common to Aristotelian diction, used when the philosopher wishes to speak about the essence of a particular thing. Most students translate the phrase as “essence” by rote, because they have not the faintest conception on how to penetrate the meaning of this four-word hieroglyphic.

Let us begin by discussing what this construction consists of at its most basic level. Fundamentally the phrase is an articular infinitive. Dr. Smyth tells us that, “The articular infinitive, while having the character of a substantive, retains the functions of a verb” (See Smyth, 2025 and following). The “character” of a substantive means that we are able to decline the infinitive as a neuter singular noun, if we place the appropriately declined definite article (τό, τοῦ, τῷ, τό) in front of it. Thus, τὸ ποιεῖν can be translated not merely as “to make,” but also as “making.” With this in mind, τὸ εἶναι, is “to be” or “being,” often simplified by most translators to “essence.”

This leaves us with the two inner terms, τί ἦν. First let us look at the imperfect ἦν. In Smyth 1901-1902 we are told that the imperfect can be used for the present tense. Liddell and Scott (εἰμί F. bottom of entry) inform us that ἦν is sometimes used as the present, corroborating the account given by Smyth. Liddell and Scott also make mention of Aristotle’s exact phrase, remarking that, “τὸ τί ἦν εἶναι expresses the essential nature of a thing.” Thus the ἦν is actually an ἐστί, at least for translation purposes.

The LSJ entry is further helpful in determining the meaning of τί ἦν as a two-word phrase. It points out that τί ἦν, in the phrase τὸ τί ἦν εἶναι, takes the place of a very similar articular infinitive, but with a dative phrase, such as τὸ ἀγαθῷ εἶναι, which can be seen in Prior Analytics 67b12 and De Anima 429b10. τί ἦν is therefore really (τῷ) τί ἦν. τί, of course, is the interrogative pronoun, “what.” The phrase τί ἦν means, “what is it?” or as an indirect interrogative, which it could also be, “what it is.”

Putting it all together in a different order we have, τὸ εἶναι “being,” (τῷ) τί ἦν “for what is it?” or as an indirect interrogative, “for what it is.” Very often when there is a dative with a verb like εἰμί, it is construed as a dative of possession, which can be translated as a genitive. We could translate τὸ τί ἦν εἶναι as, “The essence/being of what it is.” The mystery of the phrase is solved. We are nevertheless saddled with an uncharacteristically unwieldy phrase to describe a common Greek philosophical term.