slaves, slavery necessarily involves a waste of human power; for not only is slave labor less productive than free labor, but the power of masters is likewise wasted in holding and watching their slaves, and is called away from directions in which real improvement lies. From first to last, slavery, like every other denial of the natural equality of men, has hampered and prevented progress. Just in proportion as slavery plays an important part in the social organization, does improvement cease. That in the classical world slavery was so universal, is undoubtedly the reason why the mental activity which so polished literature and refined art never hit on any of the great discoveries and inventions which distinguish modern civilization. No slave holding people ever were an inventive people. In a slave holding community the upper classes may become luxurious and polished; but never inventive. Whatever degrades the laborer and robs him of the fruits of his toil, stifles the spirit of invention and forbids the utilization of inventions and discoveries even when made. To freedom alone is given the spell of power which summons the genii in whose keeping are the treasures of earth and the viewless forces of the air.
The law of human progress, what is it but the moral law? Just as social adjustments promote justice, just as they acknowledge the equality of right between man and man, just as they insure to each the perfect liberty which is bounded only by the equal liberty of every other, must civilization advance. Just as they fail in this, must advancing civilization come to a halt and recede. Political economy and social science cannot teach any lessons that are not embraced in the simple truths that were taught to poor fishermen and Jewish peasants by One who eighteen hundred years ago was crucified—the simple truths which, beneath the warpings of selfishness and the distortions of superstition, seem to underlie every religion that has ever striven to formulate the spiritual yearnings of man.