If it is allowable at this point to generalize from the facts given, it must be said that the family life is essentially a device of nature for the preservation of offspring through a more or less prolonged infancy. The family group and the instincts upon which it rests were undoubtedly, therefore, instituted by natural selection. Summing up, we may say, then, the animal family group owes its existence, first, to the production of child or immature forms that need more or less prolonged care; secondly, to the prolongation of this period of immaturity in the higher animals, and especially in man; thirdly, to the development, parallel with these two causes, of parental instincts which keep male and female together for the care of the offspring. It is evident, then, that the family life rests, not upon sex attraction, but upon the fact of the child and the corresponding psychological fact of parental instinct. The family, then, has been created by the very conditions of life itself and is not a man-made institution. The Origin of the Family in the Human Species.--Two great theories of the origin of the family in the human species have in the past been more or less accepted, and these we must now examine and criticize. First, the traditional theory that the human family life was from the beginning a pure monogamy. Secondly, the so-called evolutionary theory that the human family life arose from confused if not promiscuous sex relations. The first of these theories, favored both by the Bible and Aristotle, held undisputed sway down to the middle of the nineteenth century. Then, after the publication of Darwin's _Origin of Species_ in 1859, certain social theorists began to put forward the second theory in the name of evolution. In order that we may see precisely what the origin of the human family life was, and its primitive form, we must now proceed to criticize these two theories, especially the last, which is known as the hypothesis of a primitive state of promiscuity.