Plato, Phaedo 99d-e
“So it seemed to me, he said, that after these travails, since I had come away with nothing while examining reality, that I should be careful not to suffer the very thing which people who gaze at the sun during an eclipse do. For some of them go blind, I think, unless they examine the sight in water or something like that. I mulled over this sort of thing and I feared that my soul might be similarly blinded should I try to grasp these matters with my eyes and each of my other senses. That’s why it seemed right to me to retreat into ideas and use them to examine the truth of reality.”
Ἔδοξε τοίνυν μοι, ἦ δ’ ὅς, μετὰ ταῦτα, ἐπειδὴ ἀπειρήκη τὰ ὄντα σκοπῶν, | δεῖν εὐλαβηθῆναι μὴ πάθοιμι ὅπερ οἱ τὸν ἥλιον ἐκλείποντα θεωροῦντες καὶ σκοπούμενοι πάσχουσιν· διαφθείρονται γάρ που ἔνιοι τὰ ὄμματα, ἐὰν μὴ ἐν ὕδατι ἤ τινι τοιούτῳ σκοπῶνται τὴν εἰκόνα αὐτοῦ. τοιοῦτόν τι καὶ ἐγὼ διενοήθην, καὶ ἔδεισα μὴ παντάπασι τὴν ψυχὴν τυφλωθείην βλέπων πρὸς τὰ πράγματα τοῖς ὄμμασι καὶ ἑκάστῃ τῶν αἰσθήσεων ἐπιχειρῶν ἅπτεσθαι αὐτῶν. ἔδοξε δή μοι χρῆναι εἰς τοὺς λόγους καταφυγόντα ἐν ἐκείνοις | σκοπεῖν τῶν ὄντων τὴν ἀλήθειαν.
While reading this the other day, I discovered I was not the only one: