The existence of morality presupposes the existence of commandments of duty, and of an authority. Among animals, as well as among human beings, we find recognized authority and can discern the principles of action which constitute the duty of any particular animal. Authority among the lower animals is based on might, which is, indeed, the universal source of authority, without which no authority can exist. Personal authority is but a particular form of the authority of circumstances; and to this authority every creature must be subject. It consists of two factors: the outer authority of the environment, and the inner authority of impulse. Duty is obedience to authority. The duty of the organism consists in action that corresponds to these two authorities, following the direction given as the resultant of the mixture of the two components. That is, that manner of life is right or moral which renders the life of the organism the fullest possible under the circumstances. The unreasoning organism is unconsciously drawn to seek this maximum, while the reasoning being seeks it through reflection. The impulse to happiness includes, therefore, for the reasoning being, the impulse to morality; or, ideally expressed, the relative morality equals the relative happiness; morality and happiness are the same thing. An authority without the means of enforcing itself is a self-contradiction. The means by which nature makes its authority felt is organic excitation. In proportion to its strength, an excitation produces sensation, in case it is not too weak to make itself felt at all. Every excitation has a definite significance and may come from without or within. Pleasant excitations are always, primarily, the feeling of the stilling of pain, though there are pains, such as, for instance, that of a wound, the toothache, headache, an aching corn, which have no corresponding feeling of pleasure. Nor is pleasure the only offspring of pain, since pain may bring forth pain. Pleasure depends, in its character as pleasure as well as in its strength, on the feeling preceding it in the organism; that is, its quality is the result, not of the degree of organic excitation, but of the order of succession of the feelings. For this reason, the same feeling which brings pleasure to one individual may bring pain to another.