On the one hand, the life drives promote survival by avoiding extreme unpleasure and any threat to life. On the other hand, the death drive functions simultaneously toward extreme pleasure, which leads to death. Freud addressed the conceptual dualities of pleasure and unpleasure, as well as sex/life and death, in his discussions on masochism and sadomasochism. The tension between life drive and death drive represented a revolution in his manner of thinking.