The first caste was the priestly one, the second the warrior caste. We never find that the temporal relationships which emerge in the course of evolution are the same as those which show themselves externally in space. I beg you to note that if a spatial relationship is to become a temporal one, it occurs in the ratio of four to seven, occurs in such a way that the fourfold expands to sevenfold. Thus during the fifth root-race the four castes find their outward expression in time in the gradual training to independence of the seven sub-races. The ratio of four to seven comes from a quite specific law.