He thus makes slavery a humanitarian institution, and the slave a real member of the family.667 But the admission most fatal to his theory is in agreeing that the slave qua man may be a subject of friendship,668 and in advocating his manumission as a reward for good behavior. With this, the attempted distinction between him, qua slave and qua man, utterly breaks down, and the existence of natural slaves is virtually denied.669 Thus the great champion of slavery in the ancient world, by his very defense of it, repudiates its right as a natural institution. His actual conception of the relation is, indeed, not far from the ideal of Plato, a union for the best mutual service of rulers and ruled, in which the slave receives from his master a moral exchange value for his physical service.670
There is a certain economic and moral truth, also, in the attitude of Aristotle toward slavery, that, as Ruskin has observed,671 higher civilization and culture must have a foundation of menial labor, and that the only justification of such a situation is in the assumption that some are naturally fitted for the higher, and some for the lower, sphere.672
Such modern laborers are not technically slaves, but Aristotle would insist that they are in a still worse condition, since they are deprived of the humanizing and moralizing influences of a rational master. The plausibility of such a contention would be well illustrated by the wretched condition of multitudes of negroes after the Civil War, as also by the hopeless life of a large portion of the modern industrial army.
Moreover, the economic slavery of many of the common toilers today is less justifiable than the domestic slavery advocated by Aristotle, for it too often means a life of indolence and self-indulgence for the masters, instead of that Greek leisure which gave opportunity for higher activity.673