[260] Philo, Qu. De. S. Immut. p. 298, D (the same in the spurious treatise De Mundo, p. 1154, E): ἡ δὲ [ἕξις = ποιότης] ἐστὶ πνεῦμα ἀντιστρέφον ἐφ’ ἑαυτό. ἄρχεται μὲν γὰρ ἀπὸ τῶν μέσων ἐπὶ τὰ πέρατα τείνεσθαι, ψαῦσαν δὲ ἄκρας ἐπιφανείας ἀνακάμπτει πάλιν, ἄχρις ἂν ἐπὶ τὸν αὐτὸν ἀφίκηται τόπον, ἀφ’ οὗ τὸ πρῶτον ὡρμίσθη. ἕξεως ὁ συνεχὴς οὗτος δίαυλος ἄφθαρτος, κ.τ.λ. Qu. Mund. S. Incorr. 960, D [De Mundo, 1169, A]: ἡ δ’ [ἕξις] ἐστὶ πνευματικὸς τόνος. There can be no doubt that Philo is describing the Stoic teaching in these passages. The same idea is also used to explain the connection between the soul and the body. The unity of the universe is proved by the fact that the Divine Spirit pervades it. Further particulars hereafter. Conf. Alex. Aphr. De Mixt. 142, a: ἡνῶσθαι μὲν ὑποτίθεται [Χρύσιππος] τὴν σύμπασαν οὐσίαν πνεύματός τινος διὰ πάσης αὐτῆς διήκοντος, ὑφ’ οὗ συνάγεταί τε καὶ συμμένει καὶ σύμπαθές ἐστιν αὑτῷ τὸ πᾶν. (That must be the reading, the next sentence containing τῶν δὲ, κ.τ.λ. Conf. 143, b). Alex. 143, b, carefully denies the statement, that the all-penetrating Breath keeps things together. [261] Plut. Com. Not. 45. See p. 129, 3. Sen. Ep. 117, 2: Placet nostris, quod bonum est, esse corpus, quia quod bonum est, facit: quidquid facit corpus est ... sapientiam bonum esse dicunt: sequitur, ut necesse sit illam corporalem quoque dicere. Conf. p. 129, 1. [262] This is the conception of τόνος, upon which the strength of the soul depends, as well as the strength of the body. Cleanthes, in Plut. Sto. Rep. 7, 4, p. 1034: πληγὴ πυρὸς ὁ τόνος ἐστὶ κἂν ἱκανὸς ἐν τῇ ψυχῇ γένηται πρὸς τὸ ἐπιτελεῖν τὰ ἐπιβάλλοντα ἰσχὺς καλεῖται καὶ κράτος. Stob. Ecl. ii. 110: ὥσπερ ἰσχὺς τοῦ σώματος τόνος ἐστὶν ἱκανὸς ἐν νεύροις, οὕτω καὶ ἡ τῆς ψυχῆς ἰσχὺς τόνος ἐστὶν ἱκανὸς ἐν τῷ κρίνειν καὶ πράττειν καὶ μή. All properties may be classed under the same conception of tension. See p. 127, 5 and Plut. Com. Not. 49, 2, p. 1085: γῆν μὲν γὰρ ἴσασι καὶ ὕδωρ οὔτε αὑτὰ συνέχειν οὔτε ἕτερα, πνευματικῆς δὲ μετοχῇ, καὶ πυρώδους δυνάμεως τὴν ἑνότητα διαφυλάττειν· ἀέρα δὲ καὶ πῦρ αὑτῶν τ’ εἶναι δι’ εὐτονίαν ἐκτατικὰ καὶ τοῖς δυσὶν ἐκείνοις ἐγκεκραμένα τόνον παρέχειν καὶ τὸ μόνιμον καὶ οὐσιῶδες. Ps. Censorin. Fragm. c. 1, p. 75, Jahn: Initia rerum eadem elementa et principia dicuntur. Ea Stoici credunt tenorem atque materiam; tenorem, qui rarescente materia a medio tendat ad summum, eadem concrescente rursus a summo referatur ad medium. Here tenor or τόνος is made equivalent to πνεῦμα. Seneca, however, Nat. Qu. ii. 8, conf. vi. 21, endeavours to show that intentio belongs to spiritus more than to any other body.