Abstract

The aim of the paper is to compare two kinds of anti-realism about possible worlds: a version of instrumentalism and fictionalism. The former is inspired by M. Eklund’s paper Fiction, indifference and ontology, according to which ontologically uncommitted truth conditions for possible-world sentences are reducible to their instrumental utility and truth conditions of their literally true interpretations. The latter is inspired by S. Yablo’s work on fictionalism, according to which whenever we engage in possible-world talk, we engage in a game of make-believe, pretending that there exist such entities as possible worlds and possiblia , which makes possible-world sentences fictionally true within the game of make-believe. Instrumentalists promise to achieve ontologically uncommitted interpretation of possible-world talk without incurring ideological costs to which fictionalists are obliged, because of their doctrine of fictional truth. Contrary to that, I argue that one needs to tell a story why one finds possible-world talk a useful device and that fictionalists’ doctrine of fictional truth can be taken as an attempt to provide such an explanation. For example, most of fictionalists — by trying to save realists’ semantics for possible-world talk — can save to some degree such features of this talk as extensionality, which is partially responsible for its instrumental utility. Instrumentalism, on the other hand, lacks means of providing such a story. Hence, we should prefer more comprehensive account of usefulness of possible-world talk, even if it generates their own difficulties connected with the relation between truth conditions of possible-world sentences within a game of make-believe and truth conditions of literary true sentences about a realm of reality to which we wish to apply possible-world analysis. Key words ANTI-REALIZM, INSTRUMENTALISM, FICTIONALISM