Organon and Categories

Six treatises Aristotle never issued as a set, put in order and given a name by other people centuries after his death.

English, a translation held here, and your language

Original title: Κατηγορίαι
First published: 350 BCE(aged 34)
Original language: Ancient Greek

Overview

What the six treatises do together is prise the form of an argument away from its subject matter. Given that all A are B and all B are C, the conclusion holds whatever A, B and C are about, and the Prior Analytics is the first surviving attempt anywhere to write down which such patterns work and why. The order they stand in is Andronicus of Rhodes's, imposed around 40 BC; the name came later, from Alexander of Aphrodisias, who by the early third century AD was calling them an organon — an instrument, and so not a part of philosophy but the tool taken up before philosophy begins. The word was a move in a quarrel with the Stoics, who held that logic was a part of philosophy. At the head stands the Categories, the oddest of them: fifteen short chapters, unusually not divided into books at all, sorting everything that can be said of a subject into ten kinds — substance, quantity, quality, relation, place, time, and four more. Its closing sections read like an editor's appendix rather than Aristotle, and some scholars doubt the whole book is his. Transmission then split the collection in two. Boethius's Latin versions of the Categories and On Interpretation were all the West had for six hundred years; the rest returned only in the twelfth century — the Topics, the Sophistical Refutations and the Prior Analytics in Boethius's own forgotten versions, the Posterior Analytics newly translated by James of Venice from Greek manuscripts in Constantinople. Kant thought nothing was left to invent. Francis Bacon disagreed loudly enough to call his own book of 1620 the Novum Organum — the new instrument, Alexander's word taken back.

Key concepts

Why does Aristotle distinguish primary substance from species and genus?

Primary substance means an individual subject; species and genera count as secondary substances because they are said of such subjects. Aristotle needs the distinction to explain why substance can mean both what bears properties and what answers the question of kind. In the Categories, this two-level account keeps the ten categories from reducing being to abstract classification.

Why distinguish what is said of a subject from what is in it?

To be said of a subject is to apply a term to it without placing that term in it as a particular feature. Aristotle uses this distinction to separate kinds of predication: a species or genus can be said of a subject, whereas a quality or quantity belongs in one. The fifteen chapters make this grammatical-looking contrast carry ontological weight.

How do contraries differ from contradiction in Aristotle's account?

Contraries oppose one another within a range, whereas contradictories divide a claim and its denial. Aristotle's distinction matters because contraries can leave room for an intermediate condition, while a contradiction cannot leave both sides true of the same subject at once. Across the Categories' fifteen chapters, opposition becomes a tool for classifying statements and qualities, not merely a verbal conflict.

What does privation add to Aristotle's account of change?

Privation names the absence of a form that a subject could possess, not just any lack. Blindness, for example, matters only in a subject for which sight belongs. The distinction lets Aristotle describe opposition without treating every difference as a contrary; in the Categories, privation gives change a structured vocabulary linking what a thing can have with what it currently lacks.

What distinguishes a quality that admits degree from one that does not?

Some qualities admit more and less, while others do not vary by degree. Aristotle uses this test to separate kinds of quality within the ten categories, rather than treating every feature as equivalent. The distinction helps explain why a property can describe a subject yet still behave differently from quantity, relation, or the other categories.

Themes of the book

What this book returns to, gathered into themes and ordered by how much of the text each one occupies.

Kinds of Being and Inference

Can an argument keep its force when its subject changes, and can anything be said without first sorting what kind of thing it is? Across six treatises and ten kinds, Aristotle makes those questions bear on both valid inference and the structure of what can be said.

Aristotle separates the pattern of an argument from the things its terms happen to discuss: if all A are B and all B are C, the conclusion holds whatever A, B, and C name. The Categories gives that formal work an ontological starting point, sorting what can be said of a subject into ten kinds, including substance, quantity, quality, and relation. The collection thereby supports a view opposed to the Stoics: logic is an instrument taken up before philosophy, not one of its parts.

logic
substance
ontology
predication
contrariety
quantity
relationality
habit
classification
change
species
genus
quality
privation
relatives
contraries
definition
truth
opposition
degree
language
categories
time
space
motion
priority
relation
possession
affirmation and negation
correlatives

Enter a dialogue

Within this work

passages held: 84
distinct concepts: 95
by passages held, corpus-wide: #194

What this book thinks together

Every arc around the wheel is one concept in this book. A ribbon joins two the text reaches for together, and its width is how many of its passages hold both. Strongest: logic with predication.

Concept co-occurrence, strongest first 8 concepts, joined by 22 pairings. 74 shared passages in all. 48 weaker pairings reach beyond these concepts and are not drawn.
Concept	Paired concept	Shared passages
logic	predication	6
ontology	substance	6
contrariety	substance	5
genus	species	5
contrariety	logic	4
logic	ontology	4
logic	substance	4
ontology	predication	4
predication	substance	4
species	substance	4
genus	substance	3
logic	metaphysics	3
metaphysics	ontology	3
ontology	species	3
contrariety	metaphysics	2
genus	metaphysics	2
genus	ontology	2
genus	predication	2
logic	species	2
metaphysics	species	2
metaphysics	substance	2
predication	species	2

Works held

The author's work in order, this book marked in place. Your-language title first, the original beneath it where the two differ; side chips show which full texts are held.

-350 Organon and Categories (Κατηγορίαι) you are here GRCEN
-330 Constitution of Athens (Ἀθηναίων Πολιτεία)
Historians use it as a source rather than as a text to interpret, which is true of nothing else under Aristotle's name. It belongs beside the Politics, as the surviving piece of the survey that fed it.
GRCEN
-330 Politics: A Treatise on Government (Πολιτικά)
Not a finished book but lectures, with shorter pieces and marginal notes worked in — and the place where the Nicomachean Ethics was heading when it closed by saying that the study of character runs on into the study of constitutions.
GRCEN
-330 The Art of Poetry (Περὶ Ποιητικῆς)
The Rhetoric is its nearest neighbour in the corpus: nowhere else does Aristotle take an art apart from the maker's side, and nowhere else does he discuss poetry at any length.
GRCEN
Economics
Aristotle treats the same ground himself in the household economics of Politics I. These three books keep their place in his corpus on the strength of the name alone; scholarship removed them without settling on anyone else.
GRCEN
Eudemian Ethics
One of three ethical treatises transmitted under Aristotle's name, alongside the Nicomachean Ethics and the Magna Moralia — the last of the three being the one whose authenticity is disputed.
GRCEN
Metaphysics
Form, matter and cause are argued out in the Physics, not here, and the works on animals and the soul are built on the framework it lays down; what this book asks is what it takes for anything to be at all. Alexander of Aphrodisias, Avicenna, Averroes and Aquinas each built a commentary on it.
GRCEN
The "Art" of Rhetoric
The published title keeps the quotation marks around Art from Freese's 1926 Loeb edition. Its subject is public life — the assembly, the court, the funeral oration — but its form is the school's, like everything else of his that survives.
GRCEN
The Nicomachean Ethics (Ἠθικὰ Νικομάχεια)
The fullest of Aristotle's ethical treatises, and the one the tradition kept: it shares three books with the Eudemian Ethics, which covers the same ground. Its last page hands the subject over to the Politics.
GRCEN

— or open another of their works