Abstract
The three sorts of soul in Aristotle’s On Soul (nutritive, animal, and cognitive) may be understood as one insofar as each must go out of itself in order to confirm itself as itself. This feature of soul, without which there would be no distinction between inside and outside at all, proves to be the underlying theme of the Nicomachean Ethics. It is at the core of both moral virtue and intellectual virtue and points as well to the principle of their union. Rationality, whether in the form of morality or of thought, is necessarily incomplete rationality, for its perfection could become manifest only in a completed structure in which neither choice nor longing to know would have any place and in which rationality would be indistinguishable from mechanical structure. It is thus not accidental that although the moral argument of the Nicomachean Ethics seems to require that the human soul be double—with a rational part that governs and an animal part that is capable of being governed by this rational part—strictly speaking the rational part, which Aristotle likens to a father, is never really present in the argument. Its absence points to the character of reason as necessarily hidden and only showing itself as a striving for rationality. Further, it is a sign of the impossibility of ever achieving an adequate structural account of the soul.