Plato, Meno 98a

ἀγαθὰ ἐργάζονται· πολὺν δὲ χρόνον οὐκ ἐθέλουσι παραμένειν, ἀλλὰ δραπετεύουσιν ἐκ τῆς ψυχῆς τοῦ ἀνθρώπου, ὥστε οὐ πολλοῦ ἄξιαί εἰσιν, ἕως ἄν τις αὐτὰς δήσῃ αἰτίας λογισμῷ. τοῦτο δʼ ἐστίν, ὦ Μένων ἑταῖρε, ἀνάμνησις, ὡς ἐν τοῖς πρόσθεν ἡμῖν ὡμολόγηται. ἐπειδὰν δὲ δεθῶσιν, πρῶτον μὲν ἐπιστῆμαι γίγνονται, ἔπειτα μόνιμοι· καὶ διὰ ταῦτα δὴ τιμιώτερον ἐπιστήμη ὀρθῆς δόξης ἐστίν, καὶ διαφέρει δεσμῷ ἐπιστήμη ὀρθῆς δόξης. νὴ τὸν Δία, ὦ Σώκρατες, ἔοικεν τοιούτῳ τινί.

and effect all that is good; but they do not care to stay for long, and run away out of the human soul, and thus are of no great value until one makes them fast with causal reasoning. And this process, friend Meno, is recollection, as in our previous talk we have agreed. But when once they are fastened, in the first place they turn into knowledge, and in the second, are abiding. And this is why knowledge is more prized than right opinion: the one transcends the other by its trammels. Upon my word, Socrates, it seems to be very much as you say.