Indeterminacy in its various forms has been the focus of a great deal of philosophical attention in recent years. Much of this discussion has focused on the status of vague predicates such as ‘tall’, ‘bald’, and ‘heap’. It is determinately the case that a seven-foot person is tall and that a five-foot person is not tall. However, it seems difficult to pick out any determinate height at which someone becomes tall. How best to account for this phenomenon is, of course, a controversial matter. For example, some (such as Sorensen (2001) and Williamson (2002)) maintain that there is a precise height at which someone becomes tall and such apparent cases of indeterminacy merely reflects our ignorance of this fact. Others maintain that there is some genuine – and not merely epistemic – indeterminacy present is such cases and offer various accounts of how best to account for it. Supervaluationists (such as Keefe (2008)), for example, claim that the indeterminacy with respect to vague terms lies in their not having a single definite extension. Rather, each term is associated with a range of possible precise extensions or precisifications such that it is semantically unsettled which is the correct extension. One precisification of ‘tall’ might allow that anyone over five feet ten inches is tall, whereas another would only allow those over six foot to qualify; but no precisification will take someone who is five foot to be tall, and someone who is seven foot will count as tall on all precisifications. Thus – while someone who is seven foot will be determinately tall and someone who is five foot determinately not so – it will be indeterminate whether someone who stands at five foot eleven inches is tall.
Yet, it is important to stress that putative cases of indeterminacy are not limited to vague predicates of this kind. Philosophers have invoked indeterminacy in discussions of topics as diverse as moral responsibility (Bernstein (forthcoming)), identity over time (Williams (2014)), and the status of the future (Barnes and Cameron (2009)). In this paper, we focus on two areas where discussion of various kinds of indeterminacy has been commonplace: physics and fiction. We propose a new model for understanding indeterminacy across these domains and argue that it has some notable advantages when compared to earlier accounts. Treating physics and fiction cases univocally also indicates an interesting connection between indeterminacy in these two areas.