There is no man, however wise, who has not at some period of his youth said things, or even lived in a way which was so unpleasant to him in later life that he would gladly, if he could, expunge it from his memory. But he shouldn't regret this entirely, because he cannot be certain that he has indeed become a wise man - so far as any of us can be wise - unless he has passed through all the fatuous or unwholesome incarnations by which that ultimate stage must be reached. I know there are young people . . . whose teachers have instilled in them a nobility of mind and moral refinement from the very beginning of their schooldays. They perhaps have nothing to retract when they look back upon their lives; they can, if they choose, publish a signed account of everything they have ever said or done; but they are poor creatures, feeble descendants of doctrinaires, and their wisdom is negative and sterile. We cannot be taught wisdom, we have to discover it for ourselves by a journey which no one can undertake for us, an effort which no one can spare us.