The natural law is only an ordination of man to that common end of human life and to the means toward that end. As regards the minor of this second argument, an absolute dominion over his own life would give man power to stop all his human activity, yet the common end of human life is attainable only by man's activity. The stopping, or the power of stopping, all activity cannot be a means to that end. III. The natural law cannot give man a power which is opposed to the essential needs of human nature itself; but that a man should have absolute dominion over his own life is opposed to an essential need of human nature itself, therefore the natural law cannot give such a power. Dominion over his own life implies the power in man of rebelling against the subjection which he owes to God; but human nature essentially demands that man be in subjection to God, since dominion over one's own life and subjection to God are contradictory. Again, if man had absolute dominion over his own life he could stand aloof from all influx of the natural law and avoid every duty arising from that law. A law, however, cannot give a power which nullifies itself. The objection that suicide is licit because no injury can be done a man by an act if the man is willing to submit to the act, is irrelevant. The injury in suicide is not to man at all, but to God. There is also nothing in the objection that a gratuitous gift may be renounced. Life is not a gratuitous gift; it is an onerous gift with obligations inseparably affixed thereto which forbid the destruction of the gift. IV. Destruction is an act proper to a master alone. Man cannot be master of his own life; he can have dominion of things that are outside himself, distinguishable from himself, but not of the very existence of himself, which is not really distinguishable from himself. The definition of dominion supposes relation. The offices of master, father, magistrate, are relative conditions which suppose superiority over _another_ person, not over oneself. Even God is not a superior over himself, although he has all perfection. For this reason a man cannot sell himself; he can sell only his labor. God, who should have absolute dominion over all creatures, and who has, wills to confine these creatures to certain lines of action in keeping with the creature's nature. This is the law underlying even the moral law when it touches humanity; it is the eternal law coeternal with God's decree of creation, but not necessary as God is. When this law exists in the mind of God it is the eternal law; when it exists in the minds of creatures it is the natural law, governing the free acts of intellectual creatures. When the natural law becomes a motive to the human will, obliging but not forcing it, a law through knowledge within the consciousness of a man regulating his behavior, it is called the law of conscience.