It is the mind that reasons, and that controls its own reasonings, not any technical apparatus of words and propositions. This power of judging and concluding, when in its perfection, I call the Illative Sense, and I shall best illustrate it by referring to parallel faculties, which we commonly recognize without difficulty. For instance, how does the mind fulfil its function of supreme direction and control, in matters of duty, social intercourse, and taste? In all of these separate actions of the intellect, the individual is supreme, and responsible to himself, nay, under circumstances, may be justified in opposing himself to the judgment of the whole world; though he uses rules to his great advantage, as far as they go, and is in consequence bound to use them. As regards moral duty, the subject is fully considered in the well-known ethical treatises of Aristotle.(31) He calls the faculty which guides the mind in matters of conduct, by the name of _phronesis_, or judgment. This is the directing, controlling, and determining principle in such matters, personal and social. What it is to be virtuous, how we are to gain the just idea and standard of virtue, how we are to approximate in practice to our own standard, what is right and wrong in a particular case, for the answers in fulness and accuracy to these and similar questions, the philosopher refers us to no code of laws, to no moral treatise, because no science of life, applicable to the case of an individual, has been or can be written. Such is Aristotle’s doctrine, and it is undoubtedly true. An ethical system may supply laws, general rules, guiding principles, a number of examples, suggestions, landmarks, limitations, cautions, distinctions, solutions of critical or anxious difficulties; but who is to apply them to a particular case? whither can we go, except to the living intellect, our own, or another’s? What is written is too vague, too negative for our need. It bids us avoid extremes; but it cannot ascertain for us, according to our personal need, the golden mean. The authoritative oracle, which is to decide our path, is something more searching and manifold than such jejune generalizations as treatises can give, which are most distinct and clear when we least need them. It is seated in the mind of the individual, who is thus his own law, his own teacher, and his own judge in those special cases of duty which are personal to him. It comes of an acquired habit, though it has its first origin in nature itself, and it is formed and matured by practice and experience; and it manifests itself, not in any breadth of view, any philosophical comprehension of the mutual relations of duty towards duty, or any consistency in its teachings, but it is a capacity sufficient for the occasion, deciding what ought to be done here and now, by this given person, under these given circumstances. It decides nothing hypothetical, it does not determine what a man should