The knowledge of the soul admittedly contributes greatly to the advance of truth in general, and, above all, to our understanding of Nature, for the soul is in some sense the principle of animal life.
AristotleSince the branch of philosophy on which we are at present engaged differs from the others in not being a subject of merely intellectual interest — I mean we are not concerned to know what goodness essentially is, but how we are to become good men, for this alone gives the study its practical value — we must apply our minds to the solution of the problems of conduct.
Aristotle