Examining Assumptions about Vagueness

Abstract

I thank the commenters for their insightful remarks, from which I have learned much. In my article, I sought to explain psychiatric vagueness, which arises in borderline cases where there is no fact of the matter as to whether a diagnosis rightly can be said to apply.1 I argued “if psychiatric vagueness exists, then some of it is at least partially semantic” (Tilmes, 2022). A semantic account holds that vague utterances express different propositions since small gaps in how linguistic communities apply terms modify their referents, making their precise extension indeterminate.2 On my view, this best accommodates intuitions about the nature of conditions and explains historical changes in the application of psychiatric terms. A semantic account implies that we can sometimes settle diagnostic questions by attending to linguistic data and that some vagueness will remain so long as differences in language use do. I also argued that solely epistemic and ontic accounts—which attribute vagueness to ignorance and the world—come to implausible conclusions about psychiatric vagueness and fail to help us navigate it, respectively. It is worth clarifying my position here. First, I do not claim that all psychiatric vagueness is semantic, but only that some cases of it at least partially are. “This leaves open the possibility of vagueness having multiple sources” (Tilmes, 2022) and does not require abandoning all nonlinguistic considerations. Indeed, thinking that the borders of psychiatric conditions are affected by language need not entail rejecting concepts of etiology or kinds altogether, just as thinking that it is indeterminate when red turns to orange does not entail rejecting the notion that color is shaped by wavelengths of light. Second, I do not argue that diagnostic manuals or theories of psychiatric kinds necessarily reflect assumptions about vagueness, but that each account of vagueness lends itself more to certain approaches. For instance, if understanding psychiatric vagueness as a problem of language commits one to anti-realism, adopting a primarily semantic approach may give one reason to reject realist theories of psychiatry. Dan Stein contends that we should “side-step the Sorites paradox, and its notion that our language categories are in any way related to precise formulation in terms such as n and n + 1” (Stein, 2022). For instance, he notes that while the Diagnostic and Statistical Manual of Mental Disorders (DSM) requires symptoms of generalized anxiety disorder to last 6 months, the International Classification of Diseases, 11th edition, only stipulates that they last for several months. However, this does not solve the problem of vagueness so much