The more, however, the art of living is developed, the more will human beings be able to minimise their own loss of happiness through this selection of love to the advantage of the race; for married people will come more and more to delight in and preserve each other’s differences; to restrain the antipathetic contradictions in themselves; to make more conscious use of the sympathetic dissimilarities in the other for the completion of their own one-sidedness; to cease from the endeavour, so hostile to happiness, of reforming the other according to their own nature. Even now, moreover, the need of sympathy in love is so awakened, so sensitive, that the blind passion aroused by external contradictions is less and less able to overmaster it. The need of sympathy is now quickly warned when it encounters the irreconcilable contradictions which show that each is on a different plane of existence; that each belongs to a different psychological period or continent or race. This perception even now checks the development of love in many cases, where the contradiction really is a conflicting incompatibility, and not the elective affinity determined by nature into which enter both primary dissimilarities and secondary similarities. The latter results in the lovers’ contradictions forming a rich harmony, both in their own life together and in the personalities of their children. When this attraction of contradictions has once missed its mark, one still often sees that it is one and the same type that a person will love a second or third time, or even oftener, with a persistence of selection which makes it true in a way that the object of love has all the time been the same woman or man.