*Men act in opposition to conscience only under immediate and strong temptation.* The great majority of the acts of bad men are conscientious, but not therefore meritorious; for merit consists not in doing right when there is no temptation to evil, but in resisting temptation. But, as has been said, it is as natural, when there is no inducement to the contrary, to act in accordance with the fitness of things, as it is to act in accordance with what we see and hear. It is the tendency so to act, that alone renders human society possible, in the absence of high moral principle. In order to live, a man must so act with reference to outward nature; still more must he so act, in order to possess human fellowship, physical comfort, transient enjoyment, of however low a type; and the most depraved wretch that walks the earth purchases his continued being and whatever pleasure he derives from it by a thousand acts in accordance with the fitness of things to one in which he violates that fitness. *Conscience*, like all the perceptive faculties, *is educated by use*. The watchmaker’s or the botanist’s eye acquires an almost microscopic keenness of vision. The blind man’s hearing is so trained as to supply, in great part, the lack of sight. The epicure’s taste can discriminate flavors whose differences are imperceptible to an ordinary palate. In like manner, the conscience that is constantly and carefully exercised in judging of the fit and the unfitting, the right and the wrong, becomes prompt, keen, searching, sensitive, comprehensive, microscopic. On the other hand, conscience, like the senses, if seldom called into exercise, becomes sluggish, inert, incapable of minute discrimination, or of vigilance over the ordinary conduct of life. Yet it is never extinct, and is never perverted. When roused to action, even in the most obdurate, it resumes its judicial severity, and records its verdict in remorseful agony.