 It is not entirely clear that the final item discussed in this section, the multiverse view of set theory proposed by Joel Hamkins, should be described as a view of the world of set theory at all: it proposes that we should consider that there are multiple different concepts of set each of which describes its own universe (and loosely we might speak of the complex of universes as a “multiverse”), but at bottom it is being questioned whether there is properly a single world of set theory at all. But the tentative list of proposed axioms he gives for relationships between universes have some of the flavor of an alternative set theory.