Plato, Epinomis 991c

διειρημένων μὴ κατιδὼν ἐπεύξηταί τις ῥᾳστώνῃ παραλαβεῖν. πρὸς τούτοις δὲ τὸ καθʼ ἓν τῷ κατʼ εἴδη προσακτέον ἐν ἑκάσταις ταῖς συνουσίαις, ἐρωτῶντά τε καὶ ἐλέγχοντα τὰ μὴ καλῶς ῥηθέντα· πάντως γὰρ καλλίστη καὶ πρώτη βάσανος ἀνθρώποις ὀρθῶς γίγνεται, ὅσαι δὲ οὐκ οὖσαι προσποιοῦνται, ματαιότατος πόνος ἁπάντων. ἔτι δὲ τὴν ἀκρίβειαν τοῦ χρόνου ἡμῖν ληπτέον, ὡς ἀκριβῶς ἀποτελεῖ πάντα τὰ κατʼ

without the conditions here laid down. And besides these requirements, one must refer the particular thing to its generic form in our various discussions, questioning and disproving what has been wrongly stated; for it is rightly found to be altogether the finest and first of tests for the use of men, while any that pretend to be tests, without being so, are the vainest of all labors. And further, we must mark the exactness of time, how exactly it completes all the processes of the heavens, in order that he who is convinced of