Common Belief and Make-Believe

On Walton's account of make-believe, unknown facts concerning the existence and nature of props can influence fictional truth. Inspired by Lewis's and Walton's discussions of import of fictional truth, I explore the shape and tenability of an alternative account that avoids such interference of unknown facts, by making fictional truth rely on participants' common beliefs about props: conditional principles of generation are only valid if they quantify over props whose existence and nature is common belief between participants of the game of make-believe. I discuss two possible objections to the proposed account that are both based on the intuition that fictional truth should be something that is objective and independent of participants' mental states.