In the fourth chapter, Freud attempts a conjecture on the developmental history of civilization, which he supposes coincided with man learning to stand upright. This stage is followed by Freud's hypothesis from "Totem and Taboo" that human culture is bound up in an ancient Oedipal drama of brothers banding together to kill their father, and then creating a culture of rules to mediate ambivalent instinctual desires. Gradually, love of a single sexual object becomes diffused and distributed towards all of one's culture and humanity in the form of a diluted 'aim-inhibited affection'. Freud discounts the idea that this passive and non-judgmental affection for all is the pinnacle of human love and purpose. Freud notes that while love is essential for bringing people together in a civilization, at the same time society creates laws, restrictions, and taboos to try to suppress this same instinct, and Freud wonders if there may not be more than sexual desire within the term 'libido'.