Vagueness-Related Partial Belief and the Constitution of Borderline Cases

This chapter, specially written for a Philosophy and Phenomenological Research book symposium on the Stephen Schiffer’s The Things We Mean, is focused on Schiffer’s proposal there concerning the most central and important question about vagueness: namely, what, specifically, something’s being a borderline case of a vague expression consists in. Schiffer argues for a new kind of approach, according to which vagueness is constitutively a psychological phenomenon, grounded in a supposedly distinctive propositional attitude taken by practitioners of vague discourse: vagueness-related partial belief (VPB), contrasting in ways Schiffer details with standard partial belief (SPB). Two principal problems are raised for this proposal. First, on Schiffer’s account, VPB looks to be characteristic of a wider range of kinds of indeterminacy besides the targeted soritical vagueness. Second, there is an awkward dilemma arising over whether or why a thinker could not, as a matter of psychological contingency, adopt a VPB towards a precise proposition.

On the Characterization of Borderline Cases

This chapter was originally written for Gary Ostertag’s edition of the festschrift for Stephen Schiffer, Meanings and Other Things (Oxford University Press, 2016). It centres on Schiffer’s treatment of the characterization problem: the problem of saying what being a borderline case of a concept expressed by a vague expression consists in. While broadly sympathetic to Schiffer’s approach, the chapter takes issue with two aspects of it. Schiffer endorses Verdict Exclusion: the doctrine that a ‘polar verdict’ about a borderline case cannot be an expression of knowledge. This endorsement comes at too high a cost: among other things, it conflicts with the entitlement intuition—the intuition that there will be no point in a Sorites sequence at which it is mandatory to return neither of the polar verdicts. The chapter argues for agnosticism about Verdict Exclusion (‘Liberalism’). It also rejects Schiffer’s idea that a special genre of partial belief—vagueness-related partial belief—plays an essential role in characterizing the possession conditions for vague concepts.

Comparativism and the Measurement of Partial Belief

According to comparativism, degrees of belief are reducible to a system of purely ordinal comparisons of relative confidence. (For example, being more confident that P than that Q, or being equally confident that P and that Q.) In this paper, I raise several general challenges for comparativism, relating to (1) its capacity to illuminate apparently meaningful claims regarding intervals and ratios of strengths of belief, (2) its capacity to draw enough intuitively meaningful and theoretically relevant distinctions between doxastic states, and (3) its capacity to handle common instances of irrationality.