Meditations 9.8.1
Marcus Aurelius to himself
Εἰς μὲν τὰ ἄλογα ζῷα μία ψυχὴ διῄρηται, εἰς δὲ τὰ λογικὰ μία νοερὰ ψυχὴ μεμέρισται, ὥσπερ καὶ μία γῆ ἐστιν ἁπάντων τῶν γεωδῶν καὶ ἑνὶ φωτὶ ὁρῶμεν καὶ ἕνα ἀέρα ἀναπνέομεν, ὅσα ὁρατικὰ καὶ ἔμψυχα.
One soul is divided among irrational living beings; one intelligent soul is distributed among rational beings. So too there is one earth for everything earthy, and all of us who see and are alive see by one light and breathe one air.