Meta Ontology

Timothy Williamson in his article "Necessary Existents" presents a proof of the claim that everything necessarily exists using just three seemingly uncontroversial principles relating the notions of proposition with those of truth and existence. The argument, however, may be easily blocked once the distinction, introduced by R. M. Adams, between the notions of a proposition being true in a world and of (or at) a world is introduced. In this paper I defend the plausibility of the notion of a proposition's being true of a world by rejecting two criticisms of it raised by Williamson; in the final section, I present a conception of propositions, according to which they are equivalence classes of mental representations, for which at least one of the principles comes out as false.