Matters of which a man is to judge either belong to some definite art or science, or they do not. In the former case he is the best judge who has thorough acquaintance with that art or science, in the latter, the man whose powers have been developed and matured by education. A lame horse one would show to a farmer, not to the best and wisest man of one’s acquaintance; to the latter, one would apply in a difficult case of conduct. Experience answers to the first, a state of self-control to the latter.