Why Should I?

This chapter first answers the question of why conditional beliefs should obey the axioms and update rule of ranking theory. This includes a defense of the conditional theory of conditional belief that characterizes conditional belief in terms of belief and counterfactuals. Then the instrumentalist view of rationality, or normativity, underlying this answer is discussed. The chapter concludes with a discussion of conditional obligation and conditional belief.

Supererogation and conditional obligation

There are plenty of classic paradoxes about conditional obligations, like the duty to be gentle if one is to murder, and about “supererogatory” deeds beyond the call of duty. But little has been said about the intersection of these topics. We develop the first general account of conditional supererogation, with the power to solve familiar puzzles as well as several that we introduce. Our account, moreover, flows from two familiar ideas: that conditionals restrict quantification and that supererogation emerges from a clash between justifying and requiring reasons.

Commitment: some formal interpretations

We often use sentences that seem conditional in nature when we reason about normative issues, e.g. ‘If you have promised to do something, you should keep your promise’ and ‘If you have done something bad, you should apologize’. We seem to think that promise-making in some sense commits us to promise-keeping and that acting bad in some sense creates an obligation to apologize. It is, however, not obvious how we should symbolize such sentences in a formal language. The purpose of this essay is to investigate some different possible formalizations of different conditional obligation sentences. I consider seven different interpretations of the concept of commitment or conditional obligation and I say something about the logical properties of these different interpretations.