Some philosophers hold that knowledge or justification is both necessary and sufficient for rational action: they endorse knowledge–action or justification–action biconditionals. This paper offers a metaphysical challenge to these biconditionals, proceeding from a familiar question: what depends on what? If you know that p iff it is rational to act on p, do you know that p partly because it is rational to act on p, or is it rational to act on p partly because you know that p. A structurally similar question arises for justification–action biconditionals. I argue that no satisfactory answer can be given: each direction of the biconditionals supports an opposite order of explanation to the one supported by the other. Given the traditional asymmetry of metaphysical explanation, the biconditionals should therefore be rejected. While knowledge might be necessary for rational action, and it might be sufficient, it cannot be both—and the same goes for justification.

Suppose someone is brought up as an orthodox Jew, and so only eats kosher, is very conservative sexually, etc. Suppose they then find out that this Judaism stuff is just all a big mistake. If they then regret all the shrimp they could have eaten, all the sex!, this makes perfect sense. Not so, however, if someone finds out that moral realism is false, and they now regret all the fun they could have had hurting people’s feeling, etc. Even if this does make sense, there’s a strong disanalogy between the moral and the religious case. This asymmetry, on a realist picture of morality, calls for explanation. This chapter tries to explain it. The discussion engages some topics familiar from objections to Robust realism—the why-be-moral challenge, the status of de-dicto moral motivation, and whether and why we should care about the moral properties, robustly realistically understood.

Moral realism is often taken to have common sense and initial appearances on its side. Indeed, by some lights, common sense and initial appearances underlie all the central positive arguments for moral realism. We offer a kind of debunking argument, taking aim at realism’s common sense standing. Our argument differs from familiar debunking moves both in its empirical assumptions and in how it targets the realist position. We argue that if natural selection explains the objective phenomenology of moral deliberation and judgement, then this undermines arguments from that phenomenology. This results in a simpler, and in some ways more direct, challenge to realism. It is also less vulnerable to the main objections that have been leveled against such arguments. If accepted, our conclusion should make a real difference to the dialectic in this area. It means that neither realism nor its denial is the default, to-be-refuted, position.

According to a prominent view in Jewish-Halakhic literature, “mitzvot (commandments) require intention.” That is, to fulfill one’s obligation in performing a commandment, one must intend to perform the act because it’s a mitzvah; one must take the fact that one’s act is a mitzvah as her reason for doing the action. I argue that thus understood, this Halakhic view faces a revised version of Thomas Hurka’s recent dilemma for structurally similar views in ethics: either it makes it a necessary condition for the act’s being a mitzvah that one has a false belief about the act’s Halakhic status, or it commits proponents of the “mitzvot require intention” view to a sort of rational failure in performing the mitzvot. The dilemma arises, however, only if we interpret this Halakhic view as requiring one to have a belief about her act’s Halakhic status in order for it to have this status. I suggest that the dilemma can be avoided by interpreting the intention requirement as requiring a make-belief, instead of a belief. Under this understanding, Halakha (or God) doesn’t care about why one performs an act of a mitzvah, but rather about how she does it; how she sees and experiences her action. This suggests another form of worship central to Judaism—worship via make-believing.

We argue that moral laws explain particular moral facts by partly metaphysically grounding them (pace Selim Berker).

I argue that specific normative supervenience facts are explanatorily prior to the general supervenience fact.

I argue that essentialist characterizations of non-naturalism face a Euthyphro challenge.