H. P. Grice and J. L. Speranza on grading

Speranza

Urmson, "On Grading"

This paper offers a model of graded modal judgment. It begins by showing why the phenomenon is so theoretically vexing: given plausible constraints on the logic of epistemic modality, it is actually impossible to model graded attitudes toward modal claims as judgments/ascriptions of probability to modalized propositions. In response to this problem, this paper considers two alternative models, on which modal operators are non-proposition-forming operators:

(1) Moss (2015), in which graded attitudes toward modal claims are represented as judgments/ascriptions of probability to a "proxy" proposition, belief in which would underwrite belief in the modal claim.

(2) A model on which graded attitudes toward modal claims are represented as judgments/ascriptions of credence to a (non-propositional) modal representation (rather than a proxy proposition).

The second model is shown to be both semantically and mathematically tractable—a feature which does not ultimately distinguish it from Moss (2015). The second model, however, is easily integrated into our ordinary understanding of the functional role of graded attitudes toward modal claims (in both cognition and normative epistemology)—something that, I argue, represents a positive contrast with the account of Moss (2015).