As the Spanish proverb says, "He who would bring home the wealth of the Indies must carry the wealth of the Indies with him." So it is in traveling: a man must carry knowledge with him, if he would bring home knowledge.
Between falsehood and useless truth there is little difference. As gold which he cannot spend will make no man rich, so knowledge which cannot apply will make no man wise.
Every man who attacks my belief diminishes in some degree my confidence in it, and therefore makes me uneasy, and I am angry with him who makes me uneasy.
