in the absence of any verification of which sets correspond to which concrete situations, set-theory ontology cannot offer any rules concerning the existence of those entities we speak of in ordinary language. This incapacity is the source of one of the most serious charges laid at Badiou’s door (from an empiricist quarter): his set-theory ontology is a castle built in the air or an ‘ontology of a lost world’ … At the very most, set-theory ontology declares that any identity claim whatsoever concerning personal identity, or distinct events inasmuch as it is based on a well-formed formula, must separate out its ‘entity’ from a larger presupposed multiple. Such is its materialism … But then what is its function if it is not going to explain the world or sort out other discourses and their existential commitments? (2008: 94)