These three motives of action have all this common characteristic, that they point as their ultimate end to the happiness of the agent. The first seeks that happiness in external circumstances; the second and third in psychological conditions. There is, however, a fourth kind of motive which may be urged, and which is the peculiar characteristic of the intuitive school of moralists and the stumbling-block of its opponents. It is asserted that we are so constituted that the notion of duty furnishes in itself a natural motive of action of the highest order, wholly distinct from all the refinements and modifications of self-interest. The coactive force of this motive is altogether independent of surrounding circumstances, and of all forms of belief. It is equally true for the man who believes and for the man who rejects the Christian faith, for the believer in a future world and for the believer in the mortality of the soul. It is not a question of happiness or unhappiness, of reward or punishment, but of a generically different nature. Men feel that a certain course of life is the natural end of their being, and they feel bound, even at the expense of happiness, to pursue it. They feel that certain acts are essentially good and noble, and others essentially base and vile, and this perception leads them to pursue the one and to avoid the other, irrespective of all considerations of enjoyment. I have recurred to these distinctions, which were more fully discussed in the last chapter, because the school of philosophy we are reviewing furnishes the most perfect of all historical examples of the power which the higher of these motives can exercise over the mind. The coarser forms of self-interest were in stoicism absolutely condemned. It was one of the first principles of these philosophers that all things that are not in our power should be esteemed indifferent; that the object of all mental discipline should be to withdraw the mind from all the gifts of fortune, and that prudence must in consequence be altogether excluded from the motives of virtue. To enforce these principles they continually dilated upon the vanity of human things, and upon the majesty of the independent mind, and they indulged, though scarcely more than other sects, in many exaggerations about the impassive tranquillity of the sage.(201) In the Roman empire stoicism flourished at a period which, beyond almost any other, seemed unfavourable to such teaching. There were reigns when, in the emphatic words of Tacitus, “virtue was a sentence of death.” In no period had brute force more completely triumphed, in none was the thirst for material advantages more intense, in very few was vice more ostentatiously glorified. Yet in the midst of all these circumstances the Stoics taught a philosophy which was not a compromise, or an attempt to moderate the popular excesses, but which was rather in its austere sanctity the extreme antithesis of all that the prevailing examples and