290. XIX. THAT WHEN THE PARTNERS GROW OLD, IF FAVOR DOES NOT CEASE WITH THE WIFE WHEN ABILITY CEASES WITH THE MAN, THERE MAY ARISE A FRIENDSHIP EMULOUS OF CONJUGIAL FRIENDSHIP. The primary cause of the separation of minds between married partners is the lack of favor with the wife when ability and hence love ceases with the man; for in like manner as heat communicates with heat, so cold communicates with cold. That from defect of love with both partners friendship ceases, and if the destruction of private life in the home is not feared, also favor, is evident from reason and from experience. If then the man tacitly imputes the cause to himself, and the wife still perseveres in chaste favor towards him, there may result thence a friendship which, being between married partners, seems like love emulating conjugial love. That between aged partners, on the ground of their dwelling together, their dealings, and their comradeship, there is a friendship as though of conjugial love, tranquil, secure, lovely, and full of courtesy, is attested by experience.