Plutarch, How One Becomes Aware of Progress in Virtue 75c
“For neither in music nor in grammar could someone understand that he is gaining any ground in learning if he does not chip away at ignorance in these matters but instead senses the presence of an ever constant level of ignorance; nor for a sick man, should treatment fail to effect an easing or lightening and provide no perception of the affliction yielding and harming until the opposite state unfolds when the body has regained its health in every way.
No, but just as in these categories people make no progress unless they progress by the lightening of their burden, as if on a scale they are raised in the opposite direction, they do not recognize the change.
So too in the pursuit of philosophy no change nor even the perception of change must be supposed unless the soul can cast aside and cleanse itself of stupidity—up to the acquisition of the unmixed and perfect good, it clutches to an equally unmixed evil. For in one part of time or a season, the wise person transforms from a previous abject baseness to a nearly unobtainable excess of virtue, and they suddenly depart completely from a share of wickedness which was unshakeable for so great a length of time.”
οὐδὲ γὰρ ἐν μουσικοῖς τις ἢ γραμματικοῖς ἐπιδιδοὺς ἂν γνοίη μηδὲν ἐν τῷ μανθάνειν ἀπαρύτων τῆς περὶ ταῦτα ἀμαθίας ἀλλ᾿ ἴσης ἀεὶ τῆς ἀτεχνίας αὐτῷ παρούσης, οὐδὲ κάμνοντι θεραπεία μὴ ποιοῦσα ῥᾳστώνην μηδὲ κουφισμὸν ἁμωσγέπως τοῦ νοσήματος ὑπείκοντος καὶ χαλῶντος αἴσθησιν ἂν παρέχοι διαφορᾶς, πρὶν εἰλικρινῆ τὴν ἐναντίαν ἕξιν ἐγγενέσθαι παντάπασιν ἀναρρωσθέντος τοῦ σώματος. ἀλλ᾿ ὥσπερ ἐν τούτοις οὐ προκόπτουσιν, ἂν προκόπτοντες ἀνέσει τοῦ βαρύνοντος οἷον ἐπὶ ζυγοῦ πρὸς τοὐναντίον ἀναφερόμενοι μὴ γιγνώσκωσι τὴν μεταβολήν, οὕτως ἐν τῷ φιλοσοφεῖν οὔτε προκοπὴν οὔτε τινὰ προκοπῆς αἴσθησιν ὑποληπτέον, εἰ μηδὲν ἡ ψυχὴ μεθίησι μηδ᾿ ἀποκαθαίρεται τῆς ἀβελτερίας, ἄχρι δὲ τοῦ λαβεῖν ἄκρατον τὸ ἀγαθὸν καὶ τέλειον ἀκράτῳ τῷ κακῷ χρῆται. καὶ γὰρ ἀκαρεὶ χρόνου καὶ ὥρας ἐκ τῆς ὡς ἔνι μάλιστα φαυλότητος εἰς οὐκ ἔχουσαν ὑπερβολὴν ἀρετῆς διάθεσιν μεταβαλὼν ὁ σοφός, ἧς οὐδ᾿ ἐν χρόνῳ πολλῷ μέρος ἀφεῖλε κακίας ἅμα πᾶσαν ἐξαίφνης ἐκπέφευγε.