Plutarch, The Cleverness of Animals Moralia 961 a-b
“And here is the argument of Strato the Natural Philosopher demonstrating that it is not possible to sense anything at all without the power of thought. It is true that we may travel over letters with our sight and words fall on our ears which escape us since we are paying attention to other things. But later the mind returns, changes, and pursues each of the details which were overlooked. And this is what the saying means “the mind sees and the mind hears, but the rest is deaf and blind.” And so experiences which impact the eyes or ears do not yield understanding unless thought is present.
This is why Kleomenes the king, when a performance was applauded at a symposium and he was asked whether it seemed fine to him, he said that others should think about it, since he was worrying about the Peloponnese. From this it is necessary that all creatures who have perception also have understanding, if we are able to perceive through understanding.”
Καίτοι Στράτωνός γε τοῦ φυσικοῦ λόγος ἐστὶν ἀποδεικνύων ὡς οὐδ᾿ αἰσθάνεσθαι τὸ παράπαν ἄνευ τοῦ νοεῖν ὑπάρχει· καὶ γὰρ γράμματα πολλάκις ἐπιπορευομένους τῇ ὄψει καὶ λόγοι προσπίπτοντες τῇ ἀκοῇ διαλανθάνουσιν ἡμᾶς καὶ διαφεύγουσι πρὸς ἑτέροις τὸν νοῦν ἔχοντας· εἶτ᾿ αὖθις ἐπανῆλθε καὶ μεταθεῖ καὶ διώκει τῶν προειμένων ἕκαστον ἀναλεγόμενος· ᾗ καὶ λέλεκται: “νοῦς ὁρῇ καὶ νοῦς ἀκούει, τἄλλα κωφὰ καὶ τυφλά”
ὡς τοῦ περὶ τὰ ὄμματα καὶ ὦτα πάθους, ἂν μὴ παρῇ τὸ φρονοῦν, αἴσθησιν οὐ ποιοῦντος. διὸ καὶ Κλεομένης ὁ βασιλεύς, παρὰ πότον εὐδοκιμοῦντος ἀκροάματος, ἐρωτηθεὶς εἰ μὴ φαίνεται σπουδαῖον, ἐκέλευσεν ἐκείνους σκοπεῖν, αὐτὸς3 γὰρ ἐν Πελοποννήσῳ τὸν νοῦν ἔχειν. ὅθεν ἀνάγκη πᾶσιν, οἷς τὸ αἰσθάνεσθαι, καὶ τὸ νοεῖν ὑπάρχειν, εἰ τῷ νοεῖν αἰσθάνεσθαι πεφύκαμεν