According to the laws of his own nature each person necessarily desires that which he considers to be good, and avoids that which he considers to be evil. The more each person strives and is able to seek his own profit, that is to say, to preserve his being, the more virtue does he possess; on the other hand, in so far as each person neglects his own profit, that is to say, neglects to preserve his own being, is he impotent. No one, therefore, unless defeated by external causes and those which are contrary to his nature, neglects to seek his own profit or preserve his being. No one, I say, refuses food or kills himself from a necessity of his nature, but only when forced by external causes. The compulsion may be exercised in many ways. A man kills himself under compulsion by another when that other turns the right hand, with which the man had by chance laid hold of a sword, and compels him to direct the sword against his own heart; or the command of a tyrant may compel a man, as it did Seneca, to open his own veins, that is to say, he may desire to avoid a greater evil by a less. External and hidden causes also may so dispose his imagination and may so affect his body as to cause it to put on another nature contrary to that which it had at first, and one whose idea cannot exist in the mind; but a very little reflection will show that it is as impossible that a man, from the necessity of his nature, should endeavor not to exist, or to be changed into some other form, as it is that something should be begotten from nothing. The endeavor after self-preservation is the essence itself of a thing. If, therefore, any virtue could be conceived prior to this of self-preservation, the essence itself of the thing would be conceived as prior to itself, which (as is self-evident) is absurd. The endeavor after self-preservation is the primary and only foundation of virtue. For prior to this principle no other can be conceived, and without it no virtue can be conceived. No one endeavors to preserve his own being for the sake of another object. For if a man endeavored to preserve his being for the sake of any other object, this object would then become the primary foundation of virtue (as is self-evident), which is an absurdity. No one can desire to be happy, to act well and live well, who does not at the same time desire to be, to act, and to live, that is to say, actually to exist. II To act absolutely in conformity with virtue is nothing but acting according to the laws of our own proper nature. But only in so far as we understand do we act. Therefore, to act in conformity with virtue is nothing but acting, living, and preserving our being as reason directs, and doing so from the ground of seeking our own profit.[30]