Nozick emphasizes explanation as the proper aim of philosophy. This chapter discusses the question 'Why is there something rather than nothing?' which is not be simply dismissed as senseless, although there is a question about what it is whose existence we are trying to explain. The question of the limits of our understanding, and whether we could explain everything, may be 'somehow different', as Camacho puts it, from Nozick's title question, but their connection is clear. Here Nozick brings in his main idea, self-subsumption. There are many ways of being something but only one way of being nothing. Nozick uses this to introduce his egalitarianism, which puts all possibilities on a level, none being the 'natural' alternative. To draw out the implications of his egalitarianism Nozick introduces a 'fecundity assumption' (F), that all possibilities are realized. The most important criticisms of this discussion are those of Wedin. He accuses Nozick of not distinguishing properly between possibilities and possible worlds.