Aristotle's 10 Categories

Crucial Clarification: While they are often listed as ten, it's more accurate to think of them as "The Categories," a title of one of Aristotle's works. The number ten is a result of his analysis, not a predetermined list.

The Categories are, fundamentally, the most general kinds or classes into which things that exist can be divided. They are the fundamental ways of being something. They answer the question: "What kind of thing are we talking about when we say something 'is'?"

The Ten Categories (with Definitions and Examples)

Aristotle's list, from his work Categories, is as follows:

1. Substance (οὐσία, ousia)

Definition: The most fundamental category. It is what exists in its own right, independently, and is the subject to which all other categories attach. It is what a thing is.

Examples: A particular human (e.g., Socrates), a particular horse, a particular tree. (These are "primary substances.") The species "human" or the genus "animal" are "secondary substances.")

2. Quantity (ποσόν, poson)

Definition: The measurable aspect of a substance—how much or how many it is.

Examples: Two-feet long, number of pages, one gallon, continuous (like a line) or discrete (like a number).

3. Quality (ποιόν, poion)

Definition: The character or property of a substance—what kind it is.

Examples: White, knowledgeable, grammatical, sweet, square.

4. Relation (πρός τι, pros ti)

Definition: How one substance stands in relation to another.

Examples: Double, half, larger than, master, knowledge (of something), father.

5. Place (ποῦ, pou)

Definition: Where the substance is located.

Examples: In the marketplace, in the Lyceum, on Earth.

6. Time (πότε, pote)

Definition: When the substance exists or an event occurs.

Examples: Yesterday, last year, tomorrow.

7. Position (κεῖσθαι, keisthai)

Definition: The posture or arrangement of the parts of a substance. How it is situated.

Examples: Sitting, standing, lying down, bent.

8. State (ἔχειν, echein)

Definition: The condition a substance is in, often involving an external object. It's a temporary, acquired characteristic.

Examples: Shod (wearing shoes), armed, dressed.

9. Action (ποιεῖν, poiein)

Definition: What the substance is doing (the act of producing a change in something else).

Examples: Cutting, burning, speaking.

10. Affection (πάσχειν, paschein)

Definition: What is being done to the substance (the reception of a change from something else). It is the passive counterpart to Action.

Examples: Being cut, being burned, being spoken to.

A Handy Mnemonic

A handy way to remember them is through a medieval mnemonic phrase where the first letters correspond to the categories: S (Substance), Q (Quantity), Q (Quality), R (Relation), P (Place), T (Time), P (Position), S (State), A (Action), A (Affection) — resulting in the phrase:

"Socrates' Quality Quenches Reality's Perplexing Temporal Paradox, Sparking Astute Analysis."

Why They Are Important

The importance of the Categories cannot be overstated. They were foundational for over two millennia of Western philosophy, science, and logic.

1. Foundation for Logic and Predication: The Categories provide the basic structure for how we make true statements about the world. In a sentence like "Socrates is wise," Socrates is the substance (the subject), and wise is a quality (the predicate). The Categories map the logical structure of language onto the ontological structure of reality.
2. Answer to Parmenides: Pre-Socratic philosophers like Parmenides argued that change was an illusion. Aristotle's Categories provide a framework to explain change and multiplicity. A substance (Socrates) can remain the same while its qualities change (he becomes tanned), his place changes (he walks to the agora), or his state changes (he puts on a cloak).
3. The Basis of Ontology (the study of being): Aristotle shifted the question from "What is Being?" to "What does it mean to be a certain kind of thing?" The Categories are the answer. They are a taxonomy of existence itself, distinguishing the fundamental what-it-is (Substance) from the nine accidental ways it can be.
4. Framework for Scientific Inquiry: For Aristotle, to know something scientifically is to understand its essential and accidental qualities. The Categories provide the schema for classifying and defining objects of study, which was crucial for the development of natural philosophy (early science) and metaphysics.
5. Influence on History: The Categories were central to Neo-Platonic and Scholastic philosophy, most famously in the work of Thomas Aquinas. They shaped medieval thought about theology, nature, and logic.

A Simple Analogy

Think of the Categories like the fields in a database:

• Substance is the unique primary key (e.g., Product ID: #SOCRATES).
• The other nine categories are the various data fields you can fill in about that primary key:
  • Quantity: Weight = 165 lbs
  • Quality: Hair Color = None (bald)
  • Place: Location = Athens
  • Action: Current Activity = Debating
  • ...and so on.

The substance is the fundamental entry to which all other information is attached. Without it, the other data points would be meaningless. This is precisely Aristotle's point about reality.

In summary, Aristotle's Categories are a revolutionary attempt to create a logical and ontological framework for understanding the world, language, and thought itself. They are the bedrock of his entire philosophical system.