The reader will probably have gathered from the last chapter that there are four distinct motives which moral teachers may propose for the purpose of leading men to virtue. They may argue that the disposition of events is such that prosperity will attend a virtuous life, and adversity a vicious one--a proposition they may prove by pointing to the normal course of affairs, and by asserting the existence of a special Providence in behalf of the good in the present world, and of rewards and punishments in the future. As far as these latter arguments are concerned, the efficacy of such teaching rests upon the firmness with which certain theological tenets are held, while the force of the first considerations will depend upon the degree and manner in which society is organised, for there are undoubtedly some conditions of society in which a perfectly upright life has not even a general tendency to prosperity. The peculiar circumstances and dispositions of individuals will also influence largely the way in which they receive such teaching, and, as Cicero observed, "what one utility has created, another will often destroy." They may argue, again, that vice is to the mind what disease is to the body, and that a state of virtue is in consequence a state of health. Just as bodily health is desired for its own sake, as being the absence of a painful or at least displeasing state, so a well-ordered and virtuous mind may be valued for its own sake, and independently of all the external good to which it may lead, as being a condition of happiness; and a mind distracted by passion and vice may be avoided, not so much because it is an obstacle in the pursuit of prosperity, as because it is in itself essentially painful and disturbing. This conception of virtue and vice as states of health or sickness, the one being in itself a good, and the other in itself an evil, was a fundamental proposition in the ethics of Plato. It was admitted, but only to a subsidiary place, by the Stoics, and has passed more or less into all the succeeding systems. It is especially favourable to large and elevating conceptions of self-culture, for it leads men to dwell much less upon isolated acts of virtue or vice than upon the habitual condition of mind from which they spring. It is possible, in the third place, to argue in favour of virtue by offering as a motive that sense of pleasure which follows the deliberate performance of a virtuous act. This emotion is a distinct and isolated gratification following a distinct action, and may therefore be easily separated from that habitual placidity of temper which results from the extinction of vicious and perturbing impulses. It is this theory which is implied in the common exhortations to enjoy "the luxury of doing good," and though especially strong in acts of benevolence, in which case sympathy with the happiness created intensifies the feeling, this pleasure attends every kind of virtue.