There are lots of different ways in which a portion of language can end up being defective or indeterminate.

In the case of vagueness, I have argued that the source of the indeterminacy is to be found in the kind of proposition that borderline sentences express, rather than in the sentence itself.

Even though the idea that all defective sentences should receive similar diagnoses is not at all plausible, there are several phenomena that appear to bear a close relation to vagueness that one might think ought to be treated similarly. Indeterminacythat arises due to the liar paradox, in certain counterfactuals, in mathematically indeterminate statements (such as, perhaps, the continuum hypothesis), and in the open future all bear a close family resemblance to vagueness.^[190] It is natural to want to extend the non-linguistic analysis of vagueness defended here to these other examples of indeterminacy.

Problematic for this project is the existence of putative examples of genuine semantic indecision, examples that seem to call out for a linguistic explanation. The position of this book has been that vagueness is not an example of genuine semantic indecision, but that does not preclude the possibility that the phenomenon exists. In section 17.1, I will firstly consider several putative examples of semantic indecision, and outline what a non-linguistic approach to them might look like. In section 17.2, I ask whether it is possible to treat these cases completely analogously to vagueness. I raise some problems for this project and note the need for an account of semantic indecision in addition to propositional vagueness. In section 17.3, I give an account of semantic indecision in terms of my theory of propositional vagueness—one that situates it within the theory of vagueness I have been developing without compromising it.

color=black face="Times New Roman">17.1