Secondly, this principle and this conception of pre-historic times explain to us the meaning and the origin of the oldest and strangest of social anomalies--an anomaly which is among the first things history tells us--the existence of caste nations. Nothing is at first sight stranger than the aspect of those communities where several nations seem to be bound up together--where each is governed by its own rule of law, where no one pays any deference to the rule of law of any of the others. But if our principles be true, these are just the nations most likely to last, which would have a special advantage in early times, and would probably not only maintain themselves, but conquer and kill out others also. The characteristic necessity of early society as we have seen, is strict usage and binding coercive custom. But the obvious result and inevitable evil of that is monotony in society; no one can be much different from his fellows, or can cultivate his difference. Such societies are necessarily weak from the want of variety in their elements. But a caste nation is various and composite; and has in a mode suited to early societies the constant co-operation of contrasted persons, which in a later age is one of the greatest triumphs of civilisation. In a primitive age the division between the warrior caste and the priestly caste is especially advantageous. Little popular and little deserving to be popular now-a-days as are priestly hierarchies, most probably the beginnings of science were made in such, and were for ages transmitted in such. An intellectual class was in that age only possible when it was protected by a notion that whoever hurt them would certainly be punished by heaven. In this class apart discoveries were slowly made and some beginning of mental discipline was slowly matured. But such a community is necessarily unwarlike, and the superstition which protects priests from home murder will not aid them in conflict with the foreigner. Few nations mind killing their enemies' priests, and many priestly civilisations have perished without record before they well began. But such a civilisation will not perish if a warrior caste is tacked on to it and is bound to defend it. On the contrary, such a civilisation will be singularly likely to live. The head of the sage will help the arm of the soldier.