(_a_) We are capable of acting without a motive, and we do so act in numberless instances. It was a common saying among the Schoolmen, that an ass, at equal distances from two equal bundles of hay, would starve to death for lack of a motive to choose either. But have we any motive whatever in the many cases in which we choose—sometimes after the vain endeavor to discover a ground of preference—between two equally valuable, beautiful, or appetizing objects, between two equally pleasant routes to the same terminus, or between two equally agreeable modes of passing a leisure day or hour? Yet this choice, made without motive, may be a fruitful cause of motives that shall have a large influence in the future. Thus, on the route which one chooses without any assignable reason, he may encounter persons or events that shall modify his whole plan of life. The instances are by no means few, in which the most decisive results have ensued upon a choice thus made entirely without motive. (_b_) Motives of equal strength act differently on different temperaments. The same motive, when it stands alone, with no opposing motive, has not the same effect on different minds. There is in the will of every human being a certain reluctance to action—in some greater, in others less—corresponding to the _vis inertiæ_ in inanimate substances; and as the impulse which will move a wooden ball may not suffice to move a leaden ball, so the motive which will start into action a quick and sensitive temperament, may produce no effect on a person of more sluggish nature. Thus, among men utterly destitute of honesty, some are tempted by the most paltry opportunities for theft or fraud; others, not one whit more scrupulous, have their cupidity aroused only by the prospect of some substantial gain. So, too, some sincerely benevolent persons are moved to charitable actions by the slightest needs and sufferings; others, equally kind and generous, have their sympathies excited only on grave occasions and by imperative claims. Motives, then, have not a determinate and calculable strength, but a power which varies with the previous character of the person to whom they are addressed. Moreover, the greater or less susceptibility to motives from without is not a difference produced by education or surroundings; for it may be traced in children from the earliest development of character. Nor can it be hereditary; for it may be found among children of the same parents, and not infrequently between twins nurtured under precisely the same care, instruction, and discipline.