Abstract

Prima facie, modal statements are important, but it is less than obvious what their truth conditions are; my dissertation is an exploration of the relation between possible worlds and truth conditions for modal statements. What is it in virtue of which a modal statement is true or false? Some respond via an appeal to possible worlds: possibly ${\cal A}$ iff ${\cal A}$ in at least one possible world; necessarily ${\cal A}$ iff ${\cal A}$ in every possible world. I argue that there are two crucially important objections that any worlds approach to modality must face: one having to do with whether there are any worlds, and another regarding the work worlds are supposed to do. A "worlds" account meeting these objections is developed. ;i. David Lewis, who advocates a position according to which possible worlds are "concrete" objects, admits that his view is often met with an "incredulous stare." But accounts of worlds according to which they are abstract objects that are "complete," in that they represent "everything" about different ways the world could be are also problematic. As others have argued, the assumption that abstract objects are complete in this sense leads to contradiction--with the natural conclusions that there are no such objects; I accept this result, and develop my account in terms of partial worlds. ;ii. Suppose someone, pointing at a stack of books, were to assert that any ${\cal A}$ is possible iff ${\cal A}$ appears in some book in that stack. Insofar as there is no appropriate connection between the books in the stack and the world, and modal facts seem to be determined by the world, this may seem a rather bizarre thesis. What privileges these books as ones that are relevant to modality? Arguably, unless the way other worlds are is interestingly constrained by actuality, such worlds will appear as irrelevant to modal truth. My account is developed so as to demonstrate a sense in which worlds are relevant to modal truth. Along the way, other problems, including some connected with variable domains, and individuals that do not actually exist, are addressed