The difficulty which Socrates and the Socratic schools had in conceiving a man to choose deliberately what he knows to be bad for him---a difficulty which drives Aristotle into real Determinism in his account of purposed action, even while he is expressly maintaining the ``voluntariness'' and ``responsibility'' of vice---seems to be much reduced for the modern mind by the distinction between moral and prudential judgments, and the prima facie conflict between `interest' and `duty'. Being thus familiar with the conception of deliberate choice consciously opposed either to interest or to duty, we can without much difficulty conceive of such choice in conscious opposition to both. See chap. ix. §3, of this Book.