6. Dialectics, therefore, is only one part of philosophy, but the most important. Indeed, philosophy has other branches. First, it studies nature (in physics), therein employing dialectics, as the other arts employ arithmetic, though philosophy owes far more to dialectics. Then philosophy treats of morals, and here again it is dialectics that ascertains the principles; ethics limits itself to building good habits thereon, and to propose the exercises that shall produce those good habits. The (Aristotelian) rational virtues also owe to dialectics the principles which seem to be their characteristics; for they chiefly deal with material things (because they moderate the passions). The other virtues[351] also imply the application of reason to the passions and actions which are characteristic of each of them. However, prudence applies reason to them in a superior manner. Prudence deals rather with the universal, considering whether the virtues concatenate, and whether an action should be done now, or be deferred, or be superseded by another[352] (as thought Aristotle). Now it is dialectics, or its resultant science of wisdom which, under a general and immaterial form, furnishes prudence with all the principles it needs. WITHOUT DIALECTICS LOWER KNOWLEDGE WOULD BE IMPERFECT. Could the lower knowledge not be possessed without dialectics or wisdom? They would, at least, be imperfect and mutilated. On the other hand, though the dialectician, that is, the true sage, no longer need these inferior things, he never would have become such without them; they must precede, and they increase with the progress made in dialectics. Virtues are in the same case. The possessor of natural virtues may, with the assistance of wisdom, rise to perfect virtues. Wisdom, therefore, only follows natural virtues. Then wisdom perfects the morals. Rather, the already existing natural virtues increase and grow perfect along with wisdom. Whichever of these two things precedes, complements the other. Natural virtues, however, yield only imperfect views and morals; and the best way to perfect them, is philosophic knowledge of the principles from which they depend. FOURTH ENNEAD, BOOK TWO. How the Soul Mediates Between Indivisible and Divisible Essence. OUTLINE OF THE PSYCHOLOGICAL STUDY OF IV. 7.