Childhood can be thought of as the overcoming of an oscillation between transgression and transcendence. Transgression injects negation, the not, into human existence: sheer facticity, the physical situation of body and world, introduces the not of materiality, "Don't touch, it burns." Desire elicits the not of lack, "I want that toy", or more ineluctably, "I want something, I don't know what." Ignorance opens up the not of fear, "What is that shadow-thing that appears to be hurling itself at me?" Finally aggression brings forth the not of moral interdiction, "Don't hit him, hitting hurts." With the not of "Thou shalt not injure" the transcendence of alterity, the constraint of the other as the limit of the child's world is introduced.