§90.1Fr. 90
Θ. περὶ μουσικῆς ἀρχὰς μουσικῆς τρεῖς εἶναι λέγει, λύπην ἡδονὴν ἐνθουσιασμὸν, ὡς ἑκάστου τούτων παρατρέποντος ἐκ τοῦ συνήθους καὶ ἐγκλίνοντος τὴν φωνήν.
Fr. 90 Θ., in *On Music*, says that there are three principles of music: pain, pleasure, and enthusiasm, on the grounds that each of these diverts the voice from its usual state and inflects it.