The feudal system was based on inheritance of function and had two well-defined castes， the knightly， consisting originally of those whose ability to maintain a horse and equipment placed them in the rank of effective warriors， and the servile. Between these marriage was impossible Intercourse of any kind was scanty and， on the part of the superior order， contemptuous. "A boy of knightly birth was reared in ceremony. From his earliest childhood he learnt to look upon himself and his equals as of a differ-(224)-ent degree and almost of a different nature from his fellow creatures who were not of gentle condition. Heraldic pride and the distinction of degree were among his first impressions，" [3] Socially and psychologically the mediaeval nobility lived in their caste， not in the world at large.
It was the sphere of the social self； the knight looked to it and not to a general public for sympathy and recognition： he was far closer in spirit to the chivalry of hostile nations than to the commons of his own. But the plain people were out of all this， and were regarded with a contempt at least as great as that felt in our day for the Negro at the South. The whole institution of chivalry， with its attendant ideas， ideals and literature， was a thing of caste which recognized no common humanity in the lower orders of society， and whatever it did for the world in the way of developing the knightly ideal of valor， devotion and courtesy梐n ideal later transformed into that of the gentleman and now coming to pervade all classes梬as a product of caste spirit.
The feudal courts， large and small， the tournaments， festivals and military expeditions， including the crusades， were facilities of communication through which this caste， not only in single countries but throughout Europe， was enabled to have a common thought and sentiment.
Without doubt， however， the lower caste had also its unity and organization， its group traditions， customs and standards； mostly lost to us because they never achieved a literary record. This was an inarticulate caste；but it is probable that village communities were the spheres of a (225) vigorous cooperative life in which the best traits of human nature were fostered.
In India also the elaborate caste systems， although due in part to conquest， seem also to have come about by the hardening of occupation-classes. The priests， powerful because of their supposed intercourse with superhuman powers， taught their mystic traditions to their children and so built up a hereditary corporation， known， finally， as the Brahman caste. The military caste was apparently formed in a similar manner， while in industry "veneration for parental example and the need of an exact transmission of methods " [4 ] rendered all employments hereditary. In fact， says one writer， the caste system was in its origin "simply an instinctive effort for the organization of labor." [5] In the case of so intricate a caste society as that of India much may also be ascribed to the reaction of the theory upon the system. When the idea that caste is natural had become prevalent and sanctified， it tended to create caste where it would not otherwise have existed.
A settled state of society is favorable， and change hostile， to the growth of caste， because it is necessary that functions should be continuous through several generations before the principle of inheritance can become fixed. Whatever breaks up existing customs and traditions tends to abolish hereditary privilege and throw men into a rough struggle， out of which strong， coarse natures emerge as victors， to found， perhaps， a new aristocracy.