Livro 11
[550.5] p. 90a21 Ἆρ᾿ ἔστι συμφωνεῖν τὸ ὀξὺ καὶ τὸ βαρύ; ἆρ᾿ ἔστιν ἐν ἀριθμοῖς ὁ λόγος αὐτῶν;
Δείξας ἑκάστου τῶν ἐν ἄλλοις ὑπαρχόντων τὸ τί ἐστι καὶ αἴτιον εἶναι αὐτῷ ⟨τοῦ⟩ ὑπάρχειν τινὶ καὶ ὅλως τοῦ εἶναι, ἑξῆς παράδειγμα παρατίθεται τοῦ εἰ ἔστι ζητήματος, δεικνὺς ὅτι⟨ὁ τὸ⟩ εἰ ἔστι τι ζητῶν ζητεῖ εἰ μέσον ἐστί τι αὐτοῦ ὃ αἴτιόν ἐστιν αὐτῷ τοῦ εἶναι. ὁ δὲ λόγος ὁ αὐτὸς καὶ ἐπὶ τοῦ ὅτι ἔστιν. ὁ γὰρ ζητῶν, ἆρα ἔστι συμφωνεῖν τὸ ὀξὺ καὶ τὸ βαρύ, ζητεὶ μὲν εἰ ἔστι συμφωνία ὀξέος καὶ βαρέος· ἔστι δ᾿ ὃ ζητεῖ ἇρ᾿ ἔστιν ἐν ἀριθμῷ ὁ λόγος, ὃς λόγος καὶ αἴτιος τοῦ συμφωνεῖν τὸ ὀξὺ καὶ τὸ βαρὺ γίνεται. ἐν ἀμφοτέροις μὲν οὖν, καὶ ἐν τῷ εἰ ἔστι καὶ ἐν τῷ τὸ βαρὺ γίνεται. ἐν ἀμφοτέροις μὲν οὖν, καὶ ἐν τῷ εἰ ἔστι καὶ ἐν μὲν τοῦ ὅτι ἔστι ζητοῦμεν εἰ ἔστιν αἴτιον τοῦ τὸ ἕτερον τῷ ἑτέρῳ ὑπάρχει, ἐπὶ δὲ τοῦ εἰ ἔστιν εἰ [ἔστι] τὸ αὐτὸ τοῦτο, ὃ αἴτιον ὑπάρχει, καὶ αὐτὸ τῶν ὄντων τί ἐστι καὶ αὐτό ἐστι.