 Many phenomena appear to be indeterminate: macro-objects (clouds, mountains) appear to have imprecise boundaries; the future, it seems, might be genuinely open; on certain interpretations of quantum mechanics, some properties of a system (e.g., position and momentum, orthogonal spin components) cannot jointly have precise values. In these and other cases there are reasons to think that the indeterminacy is metaphysical, as opposed to merely semantic or epistemic. Elder (1996) suggests that determinables might be useful for purposes of making sense of “the idea that corresponding to (at least some) vague predicates there really are, in the world, vague properties” (1996: 150). Wilson (2013) more specifically argues that determinables and determinates provide the basis for an account of metaphysical indeterminacy (MI) having several advantages, including being reductive, compatible with classical logic, and such as to make systematic sense of MI in a wide range of cases, as follows: