Both opinions [1], methinks, are one-sided. The latter system has almost entirely disappeared from our schemes of ethics and philosophy, and is, I am inclined to think, not seldom cast out with over-fanatical zeal--(nothing assuredly is so dangerous to truth as when one-sided opinions meet with one-sided opponents). The former system has on the whole been more patiently endured, since it has the greatest capacity for warming the heart towards virtue, and has already justified its value in the case of truly great souls. Who is there that does not admire the strength of mind of a Cato, the lofty virtue of a Brutus and Aurelius, the equanimity of an Epictetus and a Seneca? But, in spite of all this, the system in question is nothing more than a beautiful aberration of the understanding, a real extreme, which in its wild enthusiasm underrates one part of our human nature, and desires to raise us into the order of ideal beings without at the same time relieving us of our humanity,--a system which runs directly contrary to all that we historically know or philosophically can explain either of the evolution of the single man or of that of the entirer race, and can in no way be reconciled with the limitations of our human soul. It is therefore here, as ever, the wisest plan to hold the balance between the two opinions, and thus reach with greater certainty the middle line of truth. But, inasmuch as a mistake has very often been committed by treating the mental powers in an exclusive way, that is, in so far as they can be considered in independence of the body, and through an intentional subordination of this same body, the aim of this present essay will be to bring into a clearer light the remarkable contributions made by the body to the workings of the soul, and the great and real influence of the animal system of sensations upon the spiritual. But this is as like the philosophy of Epicurus as the holding of virtue to be the summum bonum is stoicism. Before we seek to discover those higher moral ends which the animal nature assists us in attaining to, we must establish their physical necessity, and come to an agreement as to some fundamental conceptions.