Epictetus, fr. 36

“The truth is an eternal thing and unseen—it does not provide us a beauty which deteriorates with time nor a freedom of speech which is vulnerable to the law. Instead, it provides us with the just and the lawful by separating and refuting injustice from them.”

Ἀθάνατον χρῆμα ἡ ἀλήθεια καὶ ἀΐδιον, παρέχει δὲ ἡμῖν οὐ κάλλος χρόνῳ μαραινόμενον οὔτε παρρησίαν ἀφαιρετὴν ὑπὸ δίκης, ἀλλὰ τὰ δίκαια καὶ τὰ νόμιμα διακρίνουσα ἀπ᾿ αὐτῶν τὰ ἄδικα καὶ ἀπελέγχουσα.

Diogenes Laertius, Epicurus 31

“[Epicureans] dismiss dialectic as being uneccessary—they believe that it is enough for natural scientists to employ the normal words for things. In his Canon, Epicurus asserts that our sensory perceptions and prior experiences and conceptions are the criteria of the truth; and Epicureans also believe that the imagined movements of thoughts are the same. He articulates his own beliefs in his Brief to Herodotus and in his Kurian Beliefs. He says, “Every perception is free of thought and receptive to no memory. Because does not move under its own power or another’s, it cannot add anything or take it away. And there is nothing capable of refuting the senses. For one related perception cannot countermand another because of their equal power nor can inequivalent senses undermine those of a different capacity, since they are not judging the same domains.

Reason depends entirely on perceptions. Different kinds of senses cannot undermine each other, since we use them all. The interdependence of the senses ensures the truth of what we perceive. Our ability to see and hear is just like our ability to feel pain. This is why we must strive to make meaning about unclear things from what actually appears before us.”

Τὴν διαλεκτικὴν ὡς παρέλκουσαν ἀποδοκιμάζουσιν· ἀρκεῖν γὰρ τοὺς φυσικοὺς χωρεῖν κατὰ τοὺς τῶν πραγμάτων φθόγγους. ἐν τοίνυν τῷ Κανόνι λέγων ἐστὶν ὁ Ἐπίκουρος κριτήρια τῆς ἀληθείας εἶναι τὰς αἰσθήσεις καὶ προλήψεις καὶ τὰ πάθη, οἱ δ᾿ Ἐπικούρειοι καὶ τὰς φανταστικὰς ἐπιβολὰς τῆς διανοίας. λέγει δὲ καὶ ἐν τῇ πρὸς Ἡρόδοτον ἐπιτομῇ καὶ ἐν ταῖς Κυρίαις δόξαις. “πᾶσα γάρ,” φησίν, “αἴσθησις ἄλογός ἐστι καὶ μνήμης οὐδεμιᾶς δεκτική· οὔτε γὰρ ὑφ᾿ αὑτῆς οὔτε ὑφ᾿ ἑτέρου κινηθεῖσα δύναταί τι προσθεῖναι ἢ ἀφελεῖν· οὐδὲ ἔστι τὸ δυνάμενον αὐτὰς διελέγξαι. οὔτε γὰρ ἡ ὁμογένεια αἴσθησις τὴν ὁμογενῆ διὰ τὴν ἰσοσθένειαν, οὔθ᾿ ἡ ἀνομογένεια τὴν ἀνομογένειαν, οὐ γὰρ τῶν αὐτῶν εἰσι κριτικαί· οὔτε μὴν λόγος, πᾶς γὰρ λόγος ἀπὸ τῶν αἰσθήσεων ἤρτηται. οὔθ᾿ ἡ ἑτέρα τὴν ἑτέραν, πάσαις γὰρ προσέχομεν. καὶ τὸ τὰ ἐπαισθήματα δ᾿ ὑφεστάναι πιστοῦται τὴν τῶν αἰσθήσεων ἀλήθειαν. ὑφέστηκε δὲ τό τε ὁρᾶν ἡμᾶς καὶ ἀκούειν, ὥσπερ τὸ ἀλγεῖν· ὅθεν καὶ περὶ τῶν ἀδήλων ἀπὸ τῶν φαινομένων χρὴ σημειοῦσθαι.

Here’s a recent piece on Greek concepts of the truth from The Conversation.

Epictetus, fr. 36

“The truth is an eternal thing and unseen—it does not provide us a beauty which deteriorates with time nor a freedom of speech which is vulnerable to the law. Instead, it provides us with the just and the lawful by separating and refuting injustice from them.”

Ἀθάνατον χρῆμα ἡ ἀλήθεια καὶ ἀΐδιον, παρέχει δὲ ἡμῖν οὐ κάλλος χρόνῳ μαραινόμενον οὔτε παρρησίαν ἀφαιρετὴν ὑπὸ δίκης, ἀλλὰ τὰ δίκαια καὶ τὰ νόμιμα διακρίνουσα ἀπ᾿ αὐτῶν τὰ ἄδικα καὶ ἀπελέγχουσα.

Diogenes Laertius, Epicurus 31

“[Epicureans] dismiss dialectic as being uneccessary—they believe that it is enough for natural scientists to employ the normal words for things. In his Canon, Epicurus asserts that our sensory perceptions and prior experiences and conceptions are the criteria of the truth; and Epicureans also believe that the imagined movements of thoughts are the same. He articulates his own beliefs in his Brief to Herodotus and in his Kurian Beliefs. He says, “Every perception is free of thought and receptive to no memory. Because does not move under its own power or another’s, it cannot add anything or take it away. And there is nothing capable of refuting the senses. For one related perception cannot countermand another because of their equal power nor can inequivalent senses undermine those of a different capacity, since they are not judging the same domains.

Reason depends entirely on perceptions. Different kinds of senses cannot undermine each other, since we use them all. The interdependence of the senses ensures the truth of what we perceive. Our ability to see and hear is just like our ability to feel pain. This is why we must strive to make meaning about unclear things from what actually appears before us.”

Τὴν διαλεκτικὴν ὡς παρέλκουσαν ἀποδοκιμάζουσιν· ἀρκεῖν γὰρ τοὺς φυσικοὺς χωρεῖν κατὰ τοὺς τῶν πραγμάτων φθόγγους. ἐν τοίνυν τῷ Κανόνι λέγων ἐστὶν ὁ Ἐπίκουρος κριτήρια τῆς ἀληθείας εἶναι τὰς αἰσθήσεις καὶ προλήψεις καὶ τὰ πάθη, οἱ δ᾿ Ἐπικούρειοι καὶ τὰς φανταστικὰς ἐπιβολὰς τῆς διανοίας. λέγει δὲ καὶ ἐν τῇ πρὸς Ἡρόδοτον ἐπιτομῇ καὶ ἐν ταῖς Κυρίαις δόξαις. “πᾶσα γάρ,” φησίν, “αἴσθησις ἄλογός ἐστι καὶ μνήμης οὐδεμιᾶς δεκτική· οὔτε γὰρ ὑφ᾿ αὑτῆς οὔτε ὑφ᾿ ἑτέρου κινηθεῖσα δύναταί τι προσθεῖναι ἢ ἀφελεῖν· οὐδὲ ἔστι τὸ δυνάμενον αὐτὰς διελέγξαι. οὔτε γὰρ ἡ ὁμογένεια αἴσθησις τὴν ὁμογενῆ διὰ τὴν ἰσοσθένειαν, οὔθ᾿ ἡ ἀνομογένεια τὴν ἀνομογένειαν, οὐ γὰρ τῶν αὐτῶν εἰσι κριτικαί· οὔτε μὴν λόγος, πᾶς γὰρ λόγος ἀπὸ τῶν αἰσθήσεων ἤρτηται. οὔθ᾿ ἡ ἑτέρα τὴν ἑτέραν, πάσαις γὰρ προσέχομεν. καὶ τὸ τὰ ἐπαισθήματα δ᾿ ὑφεστάναι πιστοῦται τὴν τῶν αἰσθήσεων ἀλήθειαν. ὑφέστηκε δὲ τό τε ὁρᾶν ἡμᾶς καὶ ἀκούειν, ὥσπερ τὸ ἀλγεῖν· ὅθεν καὶ περὶ τῶν ἀδήλων ἀπὸ τῶν φαινομένων χρὴ σημειοῦσθαι.