Abstract

Deontic modals are the topic of my dissertation. All deontic modals, yes, but justification in particular, and epistemic justification even more specifically. Deontic modals operate upon performances—they appraise performances. Positively appraised, a performance is appropriate, decent, justifiable, right, permissible, or proper; negatively appraised, inappropriate, indecent, unjustifiable, wrong, impermissible, or improper. Belief and knowledge and performances in exactly the same sense that action and intention are performances: all are products of powers that are in some sense responsive to reasons. The principal difference is the direction of fit between mind and world. Knowledge and belief the product of cognitive powers aimed at adapting mind to world, action and intention the product of conative powers aimed at adapting world to mind. All are normatively evaluable and the characteristic normative appraisal of each is deontic. Epistemology, ethics, and rational choice all investigate the nature of deontic modals, differing only insofar as the central aims are epistemic, moral, or prudential in nature. In this sense, the general theory of deontic modals is the parent to epistemology, ethics, and rational choice. My project is to develop and defend a schematic theory of justification. I achieve this end by developing and defending a general theory of deontic modalities. Riffing on two pithy turns of phrase, the deontic theory may be tersely sloganized: value first and one must do the best one can. It is a teleological theory that defines all deontic concepts from the theoretically foundational notions of ability and value. Roughly, a belief is epistemically justifiable if, and only if, it is part of an epistemically optimific belief set the agent is able to have. Roughly, an act is morally justifiably if, and only if, it is part of a morally optimific action set the agent is able to perform. My pet interest is in the former. The resultant framework is enormously fruitful, especially in epistemology.