Περὶ δὲ τραγῳδίας λέγωμεν, ἀπολαβόντες αὐτῆς ἐκ τῶν εἰρημένων τὸν γινόμενον ὅρον τῆς οὐσίας. ἔστιν οὖν τραγῳδία μίμησις πράξεως σπουδαίας καὶ τελείας, μέγεθος ἐχούσης, ἡδυσμένῳ λόγῳ χωρὶς ἑκάστῳ τῶν εἰδῶν ἐν τοῖς μορίοις, δρώντων καὶ οὐ δι’ ἀπαγγελίας, δι’ ἐλέου καὶ φόβου περαίνουσα τὴν τῶν τοιούτων παθημάτων κάθαρσιν. λέγω δὲ ἡδυσμένον μὲν λόγον τὸν ἔχοντα ῥυθμὸν καὶ ἁρμονίαν, τὸ δὲ χωρὶς τοῖς εἴδεσι τὸ διὰ μέτρων ἔνια μόνον περαίνεσθαι καὶ πάλιν ἕτερα διὰ μέλους. ἐπεὶ δὲ πράττοντες ποιοῦνται τὴν μίμησιν, πρῶτον μὲν ἐξ ἀνάγκης ἂν εἴη τι μόριον τραγῳδίας ὁ τῆς ὄψεως κόσμος, εἶτα μελοποιία καὶ λέξις· ἐν τούτοις γὰρ ποιοῦνται τὴν μίμησιν. λέγω δὲ λέξιν μὲν αὐτὴν τὴν τῶν μέτρων σύνθεσιν, μελοποιίαν δὲ ὃ τὴν δύναμιν φανερὰν ἔχει πᾶσαν. ἐπεὶ δὲ πράξεώς ἐστι μίμησις, πράττεται δὲ ὑπό τινων πραττόντων, οὓς ἀνάγκη ποιούς τινας εἶναι κατά τε τὸ ἦθος καὶ τὴν διάνοιαν (διὰ γὰρ τούτων καὶ τὰς πράξεις εἶναί φαμεν ποιάς τινας, καὶ κατὰ ταύτας καὶ τυγχάνουσι καὶ ἀποτυγχάνουσι πάντες), ἔστιν δὲ τῆς μὲν πράξεως ὁ μῦθος ἡ μίμησις, λέγω γὰρ μῦθον τοῦτον τὴν σύνθεσιν τῶν πραγμάτων, τὰ δὲ ἤθη, καθ’ ἃ ποιούς τινας εἶναί φαμεν τοὺς πράττοντας, διάνοιαν δέ, ἐν ὅσοις λέγοντες ἀποδεικνύασί τι ἣ καὶ ἀποφαίνονται γνώμην. Ἀνάγκη οὖν πάσης τῆς τραγῳδίας μέρη εἶναι ἕξ, καθ᾿ἃ ποιά τις ἐστὶν ἡ τραγῳδία· ταῦτα δ’ ἐστὶ μῦθος καὶ ἤθη καὶ λέξις καὶ διάνοια καὶ ὄψις καὶ μελοποιία.
(Aristotle, Poet. 1449b21-1450a10)
But let us now discuss tragedy, taking up the definition of its essence which emerges from what has already been said. Tragedy, then, is mimesis of an action which is elevated, complete, and of magnitude; in language embellished by distinct forms in its sections; employing the mode of enactment, not narrative; and through pity and fear accomplishing the catharsis of such emotions. I use “embellished” for language with rhythm and melody, and “distinct forms” for the fact that some parts are conveyed through metrical speech alone, others again through song. Since actors render the mimesis, some part of tragedy will, in the first place, necessarily be the arrangement of spectacle; to which can be added lyric poetry and diction, for these are the media in which they render the mimesis. By “diction” I mean the actual composition of the metrical speech; the sense of “lyric poetry” is entirely clear. Since tragedy is mimesis of an action, and the action is conducted by agents who should have certain qualities in both character and thought (as it is these factors which allow us to ascribe qualities to their actions too, and it is in their actions that all men find success or failure), the plot is the mimesis of the action—for I use “plot” to denote the construction of events, “character” to mean that in virtue of which we ascribe certain qualities to the agents, and “thought” to cover the parts in which, through speech, they demonstrate something or declare their views. Tragedy as a whole, therefore, must have six components, which give it its qualities—namely, plot, character, diction, thought, spectacle, and lyric poetry. (tr. Stephen Halliwell)