instincts seldom—perhaps never—appear in isolation, but always mingle with each other in different, very varying proportions, and so make themselves unrecognizable to us. Sadism, long since known to us as a component-instinct of sexuality, would represent a particularly strong admixture of the instinct of destruction into the love impulse; while its counterpart, masochism, would be an alliance between sexuality and the destruction at work within the self, in consequence of which the otherwise imperceptible destructive trend became directly evident and palpable. The assumption of the existence of a death instinct or a destruction instinct has roused opposition even in analytical circles; I know that there is a great tendency to ascribe all that is dangerous and hostile in love rather to a fundamental bipolarity in its own nature. The conceptions I have summarized here I first put forward only tentatively, but in the course of time they have won such a hold over me that I can no longer think in any other way. To my mind they are theoretically far more fruitful than any others it is possible to employ; they provide us with that simplification, without either ignoring or doing violence to the facts, which is what we strive after in scientific work. I know that we have always had before our eyes manifestations of the destruction instinct fused with erotism, directed outwards and inwards in sadism and masochism; but I can no longer understand how we could have overlooked the universality of non-erotic aggression and destruction, and could have omitted to give it its due significance in our interpretation of life. (It is true that the destructive trend that is directed inwards, when it is not erotically tinged, usually eludes our perceptions.) I can remember my own defensive attitude when the idea of an instinct of destruction first made its appearance in psycho-analytical literature and how long it took until I became accessible to it. That others should have shown the same resistance, and still show it, surprises me less. Those who love fairy-tales do not like it when people speak of the innate tendencies in mankind towards aggression, destruction and, in addition, cruelty. For God has made them in his own image, with his own perfections; no one wants to be reminded how hard it is to reconcile the undeniable existence—in spite of all the protestations of Christian Science—of evil with His omnipotence and supreme goodness. The devil is, in fact, the best way out in acquittal of God; he can be used to play the same economic rôle of outlet as Jews in the world of Aryan ideals. But even so, one can just as well hold God responsible for the existence of the devil as for the evil he personifies. In view of these difficulties, it is expedient for every man to make humble obeisance on suitable occasions in honour of the high-minded nature of men; it will assist him to become universally beloved and much shall be forgiven unto him on account of it.[20]