De anima libri mantissa
Alexander of Aphrodisias
Alexander of Aphrodisias. Alexandri Aphrodisiensis Praeter Commentaria Scripta Minora, Pars 1. (Supplementum Aristotelicum, Volume 2. 1). Bruns, Ivo, editor. Berlin: Reimer, 1887.
ἔτι εἰ πῦρ τὸ ἐκπεμπόμενόν ἐστι, κατὰ φύσιν ἂν εἴη αὐτῷ ἡ εἰς τὸ ἄνω κίνησις.
ὥστε ἐχρῆν ἡμᾶς μὴ ὁμοίως ὁρᾶν ἄνω τε καὶ κάτω ὁρῶντας, ἀλλὰ ἄνω μὲν ῥᾷον, κάτω δὲ βιαζομένους καὶ μόγις.
ἔτι εἰ δι᾿ ἀκτίνων τὸ ὁρᾶν, ἁφή τις ἡ ὄψις ἔσται καὶ κατὰ ἁφὴν ἡ τῶν ἀκτίνων ἀντίληψις.