That is why we give to children a proverb, or that which the Greeks call Chreia, to be learned by heart; that sort of thing can be comprehended by the young mind, which cannot as yet hold more. For a man, however, whose progress is definite, to chase after choice extracts and to prop his weakness by the best known and the briefest sayings and to depend upon his memory, is disgraceful; it is time for him to lean on himself. He should make such maxims and not memorize them. For it is disgraceful even for an old man, or one who has sighted old age, to have a note-book knowledge. "This is what Zeno said." But what have you yourself said? "This is the opinion of Cleanthes." But what is your own opinion? How long shall you march under another man's orders? Take command, and utter some word which posterity will remember. Put forth something from your own stock.