Imitation as the principle common to the arts

Aristotle announces his subject — poetry in itself and its various kinds — and immediately establishes the foundational claim: all poetry, and all the arts, are modes of imitation. Epic poetry, tragedy, comedy, dithyrambic poetry, flute music, lyre music — all are imitations. They differ from one another in three ways: in their medium (rhythm, language, harmony, or some combination), in their objects (actions of persons of higher or lower moral type), and in their manner (narrative or dramatic, in one's own person or through characters speaking and acting).

Aristotle works through the arts systematically. Flute and lyre use only harmony and rhythm. Dancing uses rhythm alone — but even dancing imitates character, emotion, and action through rhythm. Poetry uses language alone, in prose or verse — and Aristotle notes that this art has had no general name: we use the word "poet" only for those who write in verse, which conflates the medium with the art itself. A writer of prose philosophical dialogues and a writer of epic verse are both imitators, but only the second gets the title "poet."

Some arts — tragedy and comedy — combine all three means: rhythm, harmony, and language. But they combine them differently. In dithyrambic poetry, all three are used throughout; in tragedy and comedy, they alternate. This combinatorial analysis is typical of Aristotle's method: start with the broadest category, divide by principle, arrive at the specific. Chapter 1 establishes the category (imitation), the three dimensions of difference (medium, object, manner), and the programme for what follows.