it takes before a species of plant or animal disappears in face of a better adapted species. Ideas and customs, beliefs and institutions, have always lingered just as long in face of their successors, and the competition is not less keen nor less prolonged, because it is for one or other inevitably destined to be hopeless. History, like geology, demands the use of the imagination, and in proportion as the exercise of the historic imagination is vigorously performed in thinking of the past, will be the breadth of our conception of the changes which the future has in store for us, as well as of the length of time and the magnitude of effort required for their perfect achievement[30]. This much, concerning moderation in political practice. No such considerations present themselves in the matters which concern the shaping of our own lives, or the publications of our social opinions. In this region we are not imposing charges upon others, either by law or otherwise. We therefore owe nothing to the prejudices or habits of others. If any one sets serious value upon the point of difference between his own ideal and that which is current, if he thinks that his 'experiment in living' has promise of real worth, and that if more persons could be induced to imitate it, some portion of mankind would be thus put in possession of a better kind of happiness, then it is selling a birthright for a mess of pottage to abandon hopes so rich and generous, merely in order to avoid the passing and casual penalties of social disapproval. And there is a double evil in this kind of flinching from obedience to the voice of our better selves, whether it takes the form of absolute suppression of what we think and hope, or only of timorous and mutilated presentation. We lose not only the possible advantage of the given change. Besides that, we lose also the certain advantage of maintaining or increasing the amount of conscientiousness in the world. And everybody can perceive the loss incurred in a society where diminution of the latter sort takes place. The advance of the community depends not merely on the improvement and elevation of its moral maxima, but also on the quickening of moral sensibility. The latter work has mostly been effected, when it has been effected on a large scale, by teachers of a certain singular personal quality. They do nothing to improve the theory of conduct, but they have the art of stimulating men to a more enthusiastic willingness to rise in daily practice to the requirements of whatever theory they may accept. The love of virtue, of duty, of holiness, or by whatever name we call this powerful sentiment, exists in the majority of men, where it exists at all, independently of argument. It is a matter of affection, sympathy, association, aspiration. Hence, even while, in quality, sense of duty is a stationary factor, it is constantly changing in quantity. The amount of conscience in different communities, or in the same community at