Aristotle, Poetics 1452a (Full text in the Scaife Viewer)
“Reversal [peripeteia] is change to the opposite of what happened before as has been said and this is also, as we argue, according to either probability or necessity. This is what happens in Oedipus when the person who comes to relieve Oedipus and rid him of his fear about his mother is actually the one who does the opposite by revealing who he really is. This also happens in the Lynceus where while one person is dragged away to die and Danaus is following in order to kill him, it turns out that Danaus dies and the other is preserved.
Recognition [anagnôrisis] is a change from ignorance to knowledge, just as the name implies, in the direction of friendship or enmity when the matters are also pertaining to success or failure. The best recognition of all is the one which occurs at the same time as a reversal, as in Oedipus.”
Ἔστι δὲ περιπέτεια μὲν ἡ εἰς τὸ ἐναντίον τῶν πραττομένων μεταβολὴ καθάπερ εἴρηται, καὶ τοῦτο δὲ ὥσπερ λέγομεν κατὰ τὸ εἰκὸς ἢ ἀναγκαῖον, οἷον ἐν τῷ Οἰδίποδι ἐλθὼν ὡς εὐφρανῶν τὸν Οἰδίπουν καὶ ἀπαλλάξων τοῦ πρὸς τὴν μητέρα φόβου, δηλώσας ὃς ἦν, τοὐναντίον ἐποίησεν· καὶ ἐν τῷ Λυγκεῖ ὁ μὲν ἀγόμενος ὡς ἀποθανούμενος, ὁ δὲ Δαναὸς ἀκολουθῶν ὡς ἀποκτενῶν, τὸν μὲν συνέβη ἐκ τῶν πεπραγμένων ἀποθανεῖν, τὸν δὲ σωθῆναι. ἀναγνώρισις δέ, ὥσπερ καὶ τοὔνομα σημαίνει, ἐξ ἀγνοίας εἰς γνῶσιν μεταβολή, ἢ εἰς φιλίαν ἢ ἔχθραν, τῶν πρὸς εὐτυχίαν ἢ δυστυχίαν ὡρισμένων· καλλίστη δὲ ἀναγνώρισις, ὅταν ἅμα περιπετείᾳ γένηται, οἷον ἔχει ἡ ἐν τῷ Οἰδίποδι
“The best kind of recognition of all comes from the plot events themselves when the surprise comes out of probable events. This is the case in Sophokles’ Oedipus or in Iphigenia. For only these kinds of recognitions can happen without manufactured signs and necklaces. The second best kinds are from logical reasoning.”
πασῶν δὲ βελτίστη ἀναγνώρισις ἡ ἐξ αὐτῶν τῶν πραγμάτων, τῆς ἐκπλήξεως γιγνομένης δι᾿ εἰκότων, οἷον ἐν τῷ Σοφοκλέους Οἰδίποδι καὶ τῇ Ἰφιγενείᾳ· εἰκὸς γὰρ βούλεσθαι ἐπιθεῖναι γράμματα. αἱ γὰρ τοιαῦται μόναι ἄνευ τῶν πεποιημένων σημείων καὶ περιδεραίων. δεύτεραι δὲ αἱ ἐκ συλλογισμοῦ.
“[Tragedy] is vivid in both reading and the performance of the plays. And the outcome of its practice of imitation comes in shorter time: a greater density of experience is more pleasurable than if it is paced out over time. Imagine if someone wrote Sophokles’ Oedipus in the same number of epic verses as the Iliad?”
εἶτα καὶ τὸ ἐναργὲς ἔχει καὶ ἐν τῇ ἀναγνώσει καὶ ἐπὶ τῶν ἔργων· ἔτι τῷ ἐν ἐλάττονι μήκει τὸ τέλος τῆς μιμήσεως εἶναι (τὸ γὰρ ἀθροώτερον ἥδιον ἢ πολλῷ κεκραμένον τῷ χρόνῳ, λέγω δ᾿ οἷον εἴ τις τὸν Οἰδίπουν θείη τὸν Σοφοκλέους ἐν ἔπεσιν ὅσοις ἡ Ἰλιάς)·