"Passionate mutual love while it lasts... breaks down the hard walls of the ego, producing a new being composed of two in one. Nature did not construct human beings to stand alone, since they cannot fulfil her biological purpose except with the help of another; and civilized people cannot fully satisfy their sexual instinct without love... Those who have never known the deep intimacy and the intense companionship of happy mutual love have missed the best thing that life has to give; unconsciously, if not consciously, they feel this, and the resulting disappointment inclines them towards envy, oppression and cruelty. To give due place to passionate love should be therefore a matter which concerns the sociologist, since, if they miss this experience, men and women cannot attain their full stature, and cannot feel towards the rest of the world that kind of generous warmth without which their social activities are pretty sure to be harmful."