The greatly increased importance which the Darwinian theory has given to heredity should tend to make men more sensible of the first of these duties. In marriage there are not only reciprocal duties between the two partners; there are also, more than in any other act of life, plain duties to the race. The hereditary nature of insanity and of some forms of disease is an indisputable truth. The hereditary transmission of character has not, it is true, as yet acquired this position; and there is a grave schism on the subject in the Darwinian school. But that it exists to some extent few close observers will doubt, and it is in a high degree probable that it is one of the most powerful moulding influences of life. No more probable explanation has yet been given of the manner in which human nature has been built up, and of the various instincts and tastes with which we are born, than the doctrine that habits and modes of thought and feeling indulged in and produced by circumstances in former generations have gradually become innate in the race, and exhibit themselves spontaneously and instinctively and quite independently of the circumstances that originally produced them. According to this theory the same process is continually going on. Man has slowly emerged from a degraded and bestial condition. The pressure of long-continued circumstances has moulded him into his special type; but new feelings and habits, or modifications of old feelings and habits, are constantly passing not only into his life but into his nature, taking root there, and in some degree at least reproducing themselves by the force of heredity in the innate disposition of his offspring. If this be true, it gives a new and terrible importance both to the duty of self-culture and to the duty of wise selection in marriage. It means that children are likely to be influenced not only by what we do and by what we say, but also by what we are, and that the characters of the parents in different degrees and combinations will descend even to a remote posterity. It throws a not less terrible light upon the miscalculations of the past. On this hypothesis, as Mr. Galton has truly shown, it is scarcely possible to exaggerate the evil which has been brought upon the world by the religious glorification of celibacy and by the enormous development and encouragement of the monastic life. Generation after generation, century after century, and over the whole wide surface of Christendom, this conception of religion drew into a sterile celibacy nearly all who were most gentle, most unselfish, most earnest, studious, and religious, most susceptible to moral and intellectual enthusiasm, and thus prevented them from transmitting to posterity the very qualities that are most needed for the happiness and the moral progress of the race. Whenever the good and evil resulting from different religious systems come to be impartially judged, this consideration is likely to weigh heavily in the scale.[70]