Aristotle, Nicomachean Ethics, Book 10 51:

διὸ καὶ ἡ ἡδονὴ ἀμαυροῦται. ὀρέγεσθαι δὲ τῆσ ἡδονῆσ οἰηθείη τισ ἂν ἅπαντασ, ὅτι καὶ τοῦ ζῆν ἅπαντεσ ἐφίενται· ἡ δὲ ζωὴ ἐνέργειά τισ ἐστί, καὶ ἕκαστοσ περὶ ταῦτα καὶ τούτοισ ἐνεργεῖ ἃ καὶ μάλιστ’ ἀγαπᾷ, οἱο͂ν ὁ μὲν μουσικὸσ τῇ ἀκοῇ περὶ τὰ μέλη, ὁ δὲ φιλομαθὴσ τῇ διανοίᾳ περὶ τὰ θεωρήματα, οὕτω δὲ καὶ τῶν λοιπῶν ἕκαστοσ·