He who gives himself to a lover because he is a good man, and in the hope that he will be improved by his company, shows himself to be virtuous, even though the object of his affection turn out to be a villain, and to have no virtue; and if he is deceived he has committed a noble error. For he has proved that for his part he will do anything for anybody with a view to virtue and improvement, than which there can be nothing nobler.
Charmides. Lysis. Laches. Protagoras. Euthydemus. Cratylus. Phaedrus. Ion. Symposium (ed. 1892)