Aristotle’s Categories: 10-Fold Division of Being

(See here for the previous posts on the Categories: Chapter 1Chapter 2, Chapter 3)

In this fourth chapter of the Categories Aristotle introduces a second division of being, classifying “things said without combination.”  When considered in their most elemental form, if they can be, on Aristotle’s view things will be organized into these 10 types of categories.  In J.A. Ackrill’s considered opinion Aristotle arrived at these categorial classifications, “by observing that different types of answer are appropriate to different questions.” [2]  However he discovered this system of classification, he introduces them very briefly by exampling them with 2 or 3 instances.

Each of the things said without combination signify either substance (ousia)[1], or quantity (poson), or quality (posos), or relation (pros ti) or where (pou) or when (pote) or being in a position (keisthai) or having (echein) or doing (poiein) or being affected (paschein). And substance is, to speak generally, for example a man, a horse; and quantity for example, two cubits long, three cubits long; and quality is for example, white, grammatical; and relation is for example, double, half, greater; and where is for example, in the Lyceum, in the market; and when for example is yesterday, a year ago; and being in a position for example, reclining, sitting; and having for example, having shoes on, being armored; and to do for example, cutting, burning; and to be affected for example, to be cut, to be burnt.

In any affirmation though, none of the things mentioned is said by itself; rather in the combination of these with each other an affirmation comes about. Each affirmation seems either to be true or false, but none of the things said without combination is true or false, for example man, white, runs, wins (translation mine, Categories, 1b25-2a10). [3]

So we have rather straightforwardly, a classification that looks like this:

Substance (ousia) example: horse, man
Quantity (poson) example: two cubits long, three cubits long
Quality (posos) example: white, grammatical
Relation (pros ti) example: double, half, greater
Where (pou) example: in the Lyceum, in the market
When (pote) example: yesterday, a year ago
Being in a position (keisthai) example: reclining, sitting
Having (echein) example: having shoes on, being armoured
Doing (poiein) example: cutting, burning
Being affected (paschein) example: to be cut, to be cut

It should be noted that when Aristotle both earlier and in this chapter spoke of “things said without combination,” he must have intended this to mean the objects to which the words refer.  We can be confident of this because he gives as an example of one his categories, which are by definition said without combination, “in the Lyceum” which is two words in Greek.  Yet, on the supposition that Aristotle was referring to linguistic terms alone, of course using two words is an example of combination.  Thus, Aristotle must be referring to the concrete items for which these terms are merely used as designations.

It is mnemonically suggestive that 8 of the 10 categories begin with the letter p (Greek π).  This might be similar to the journalistic admonition to remember the “W questions,” i.e. who, when, why, where, what.  If so, this might cynically incline us to believe that these categories were chosen because they were easily accessible to Aristotle.

In the second half of this passage, Aristotle wants to emphasis that while these categorial uses are building blocks, they are not of any use when discussing truth or falsity.  We cannot discover the truth value of “horse.” In order to make it truth-evaluable we must say, “horse is white” or “horse is grammatical,” for example.

Some interpretative questions:

Is “in accordance with no combination” κατὰ μηδεμίαν συμπλοκὴν used by Aristotle as a circumlocution to avoid adding another predicate, i.e. things that are without combination are either, etc.?

Why does Aristotle preface his introduction with “to speak generally” ὡς τύπῳ εἰπεῖν about substance (or maybe all the categories, it seems ambigious)?  Is this just to say the examples he is about to give are not exhaustive, typical, or that we should refrain from inferring too much from limited examples?

Does Aristotle want us to understand, in the second paragraph, translating more literally, “In no affirmation is each of the things mentioned predicated of itself?”  Viz. “Horse is horse”  If this is so, what does this mean for how he intended his theory of predication to be employed, since we are excluding this meaning?



[1] Could be translated ‘being.’
[2] Aristotle’s Categories and De Interpretatione, Oxford, 1963, pg. 79
[3] Τῶν κατὰ μηδεμίαν συμπλοκὴν λεγομένων ἕκαστον ἤτοι (25)
οὐσίαν σημαίνει ἢ ποσὸν ἢ ποιὸν ἢ πρός τι ἢ ποὺ ἢ ποτὲ ἢ
κεῖσθαι ἢ ἔχειν ἢ ποιεῖν ἢ πάσχειν. ἔστι δὲ οὐσία μὲν ὡς
τύπῳ εἰπεῖν οἷον ἄνθρωπος, ἵππος· ποσὸν δὲ οἷον δίπηχυ,
τρίπηχυ· ποιὸν δὲ οἷον λευκόν, γραμματικόν· πρός τι δὲ
(2a.) οἷον διπλάσιον, ἥμισυ, μεῖζον· ποὺ δὲ οἷον ἐν Λυκείῳ, ἐν
ἀγορᾷ· ποτὲ δὲ οἷον χθές, πέρυσιν· κεῖσθαι δὲ οἷον ἀνάκειται,
κάθηται· ἔχειν δὲ οἷον ὑποδέδεται, ὥπλισται· ποιεῖν δὲ οἷον
τέμνειν, καίειν· πάσχειν δὲ οἷον τέμνεσθαι, καίεσθαι.

ἕκαστον δὲ τῶν εἰρημένων αὐτὸ μὲν καθ’ αὑτὸ ἐν οὐδεμιᾷ κατα- (5)
φάσει λέγεται, τῇ δὲ πρὸς ἄλληλα τούτων συμπλοκῇ
κατάφασις γίγνεται· ἅπασα γὰρ δοκεῖ κατάφασις ἤτοι
ἀληθὴς ἢ ψευδὴς εἶναι, τῶν δὲ κατὰ μηδεμίαν συμ-
πλοκὴν λεγομένων οὐδὲν οὔτε ἀληθὲς οὔτε ψεῦδός ἐστιν,
οἷον ἄνθρωπος, λευκόν, τρέχει, νικᾷ. (10)

Aristotle’s Categories: Predication with Genus and Differentiae

(See here for the previous posts on the Categories: Chapter 1, Chapter 2)

Aristotle’s philosophical writing, often opaque in style as well as content, can also venture into extended periods of intricate simplicity, innovating complexity and depth from a rather limited set of fixed, technical terms.  This is the case for much of the Categories, and chapter 3 certainly fits this description as well.  In this post, I will be continuing my quasi-commentary on Aristotle’s Categories, now arriving at chapter 3.

Whenever one thing is predicated of another as of a subject (ὑποκειμένου), as many things as are said of the thing being predicated, all of these will also be said of the subject. For example human is predicated of an individual human, and animal is predicated of a human. Therefore animal will be predicated of an individual human also. For an individual human is both a human and an animal.


Of the things differing in genus and not being subordinated to one another there are differentiae different in kind (τῷ εἴδει), for example, there are [distinct] differentiae of animal and of knowledge: footed, winged, water-dwelling, two-footed, and none of these is [a differentia] of knowledge. For [one kind] of knowledge does not differ from [another] knowledge by having two feet. Yet nothing prevents there being the same differentiae of the genera subordinate to each other. For the higher genera are predicated of the things said under them, so that as many differentiae as there are of the thing being predicated there will be of the subject as well (Translation mine, Categories 1b10-24). [1]

Aristotle begins this section with the confusingly worded, “Whenever one thing is predicated of another as of a subject (ὑποκειμένου), as many things as are said of the thing being predicated, all of these will also be said of the subject.”  Now the example that follows makes the concept he is addressing here rather clear.  If an individual human is a human, and if a human is an animal, then an individual human is an animal.  In this instance, using Aristotle’s terminology, the subject and the thing being predicated of is “the individual human,” while the thing being predicated is “human.”  (Keep in mind that I use quotation marks not to designate a mere linguistic term, but to clarify and distinguish the objects to which they refer.)

Aristotle next invokes language about genus and differentia (plural, genera and differentiae.)  Assuming that there are such entities we may roughly think of as “kinds of things,” designated as genera, then it follows that these things must be organized and distinguished from each other in some way.  For example, taking animal as a real genus, we can say that there are (at least) two “kinds”: birds and fish.  These two kinds of things, birds and fish, are each a species of the genus animal, and although they belong to the genus animal, birds and fish are distinguished from each other by differing in some salient way.  Possession of this differing property or properties, such as scales or feathers, is what makes the one animal (fish) differ from the other (bird).  Thus these properties are called differentiae.  Since this usage of genus is not to be confused with our modern classifications in biological nomenclature, we can freely apply the term genus to whatever level of kinds of things we wish.  With confidence in being philosophically consistent, in other words, we can also say that in addition to animal, fish is also a genus, with the differentiae of salt-water or fresh-water picking out two other species based on the difference of the type of water inhabited.  What Aristotle warns against in the second half of this text is being sloppy when it comes to distinctions made in one genus that do not apply to another, viz. knowledge and animal, where one applies two-footedness to knowledge.



[1] Ὅταν ἕτερον καθ’ ἑτέρου κατηγορῆται ὡς καθ’ ὑποκει- (10)
μένου, ὅσα κατὰ τοῦ κατηγορουμένου λέγεται, πάντα καὶ κατὰ τοῦ ὑποκειμένου ῥηθήσεται· οἷον ἄνθρωπος κατὰ τοῦ τι-
νὸς ἀνθρώπου κατηγορεῖται, τὸ δὲ ζῷον κατὰ τοῦ ἀνθρώπου·
οὐκοῦν καὶ κατὰ τοῦ τινὸς ἀνθρώπου τὸ ζῷον κατηγορηθήσε-
ται· ὁ γὰρ τὶς ἄνθρωπος καὶ ἄνθρωπός ἐστι καὶ ζῷον. (15)
τῶν ἑτερογενῶν καὶ μὴ ὑπ’ ἄλληλα τεταγμένων ἕτεραι
τῷ εἴδει καὶ αἱ διαφοραί, οἷον ζῴου καὶ ἐπιστήμης·
ζῴου μὲν γὰρ διαφοραὶ τό τε πεζὸν καὶ τὸ πτηνὸν καὶ τὸ
ἔνυδρον καὶ τὸ δίπουν, ἐπιστήμης δὲ οὐδεμία τούτων· οὐ γὰρ
διαφέρει ἐπιστήμη ἐπιστήμης τῷ δίπους εἶναι. τῶν δέ γε (20)
ὑπ’ ἄλληλα γενῶν οὐδὲν κωλύει τὰς αὐτὰς διαφορὰς εἶναι·
τὰ γὰρ ἐπάνω τῶν ὑπ’ αὐτὰ γενῶν κατηγορεῖται, ὥστε
ὅσαι τοῦ κατηγορουμένου διαφοραί εἰσι τοσαῦται καὶ τοῦ
ὑποκειμένου ἔσονται.

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.