A further cause arising from the development of love is certainly of not less importance--it is the beginning of life not wholly individualistic. It is in the sexual passions we must seek the origins of all social growth. This is evident. We have seen that sexual union induces durable association between the female and the male for the object of rearing the young. Here already we find that truth, which it is the chief purpose of this book to make plain, that the individual exists for the race. This is the new and practical morality of the biological view, which regards the individual as primarily the host and servant of the seed of life. And this is really of the greatest benefit to the individual. From this service to the future arises the family and the home. The familial instinct, more or less developed, may be traced far back in the scale of life; and as it gains in strength it extends from the family into a wider social love, which in some species results in the forming of societies grouped together for mutual protection and co-operation in communal activities. A rough outline of society is thus found established already in the animal kingdom. Just as there were many different forms of sexual associations among our animal ancestors, so we may observe the two chief forms of human societies, the matriarchate and the patriarchate--or the maternal and paternal family. It is the former that is the most frequent. This is what we should expect. The female, the mother, as the natural centre of the family, the male, her servant, in the procreative act; but apart from this, we find him most frequently following personal interests; the female's love for the young is stronger and more developed than his. I lay stress upon this fact, for it shows how strongly planted in woman is the maternal instinct. I doubt if any woman can ever find true expression for her nature apart from motherhood. It is in these past histories of life's development that we may find the key for its purpose and meaning to us.