It is not however free from certain ethical difficulties of its own. Thus, it might seem at first as though the care and attention that a person of mature age may bestow upon his parents is but a just and reasonable return for the benefits which he himself received from these parents in his infancy and youth. Biologically however the cases are not similar. The care of parents for their young is necessary for the perpetuation of the race. The care bestowed upon the aged and infirm who are no longer able to provide adequately for themselves is of no direct value in the struggle for existence; it may even be a disadvantage in this struggle, a luxury that can only be afforded when the struggle is relaxed or when all competing individuals or races have adopted the practice. Further, from the point of view of the race, the real equivalent that is given in return for the benefits received from parents in early life lies in the corresponding benefits bestowed upon the next generation in its turn, and the double burden of maintaining and caring for both the young and the old may be definitely beyond the powers of many. [Sidenote: Satisfactory family conditions conduce to happiness in old age] Fortunately, it but rarely happens, even at the extreme end of a long life, that the old are entirely dependent upon the care and efforts of others. In a civilised society they usually remain permanently able to provide for a considerable part of their immediate needs, and the sounder and more stable is their own and the general economic condition, the more is this the case. On the whole it is perhaps rather on the psychological than on the strictly economic side that they will be in need of assistance, and here it is that the principles that have emerged from the study of the facts and tendencies with which we have been concerned in this book may prove of use. In so far as family life is able to proceed and develop on the lines which a true morality based on sound psychological principles and an adequate psychological knowledge would seem to indicate as most desirable, it should be possible for the older members of the family to participate freely in the joys and satisfactions which they may still find within the family circle and to escape the danger of being excluded from these satisfactions, by the disappointments and misunderstandings, or by the unhappiness and bitterness that the faulty development of the family so frequently, and so disastrously, brings in its train. The old tend always to live to some extent vicariously: they find a great part of their interests and their pleasures in the contemplation of the doings of others who are younger than themselves: their own lives are projected into those of their children and their grandchildren, and by means of this projection they enjoy the most natural compensation for the decline of their own personal interests and capacities. If they have found this compensation, it may well be said