Ralph Wedgwood

Many philosophres have attempted to argue from the "Humean Theory of Motivation" (HTM) and the "Internalism Requirement" (IR) to the "Humean Theory of Practical Reason" (HTPR). This argument is familiar, but it has rarely been stated with sufficient precision. In this paper, I shall give a precise statement of this argument. I shall then rely on this statement to show two things. First, the HTPR is false: it is incompatible with some extremely plausible assumptions about weakness of will or akrasia. Second, this argument for the HTPR is invalid: even if the HTM and the IR are true, they do not provide any support whatsoever to the HTPR.

Nonreductive physicalism faces a serious objection: physicalism entails the existence of an enormous number of modal facts--specifically, facts about exactly which physical properties necessitate each mental property; and, it seems, if mental properties are irreducible, these modal facts cannot all be satisfactorily explained. The only answer to this objection is to claim that the explanations of these modal facts are themselves contingent. This claim requires rejecting "S5" as the appropriate logic for metaphysical modality. Finally, it is argued that rejecting "S5" is not too high a price to pay for nonreductive physicalism: "S5" should probably be rejected anyway.

In this book, Christopher Peacocke proposes a general theory about what it is for a thinker to be entitled to form a given belief. This theory is distinctively rationalist: that is, it gives a large role to the a priori, while insisting that the propositions or contents that can be known a priori are not in any way “true in virtue of meaning” (and without in any other way denigrating these propositions as “trivial”, or as propositions that “tell us nothing about the world”, or the like). Peacocke then applies this theory to several classical problems in epistemology — to the problem of how our sensory experiences can entitle us to form beliefs about the external world, to the problem of induction, and to the problem of what entitles us to form moral beliefs.

This paper outlines a new approach to the task of giving an account of the meaning of moral statements: a sort of "conceptual role semantics", according to which the meaning of moral terms is given by their role in practical reasoning. This role is sufficient both to distinguish the meaning of any moral term from that of other terms, and to determine the property or relation (if any) that the term stands for. The paper ends by suggesting reasons for regarding this "conceptual role semantics" approach as preferable to noncognitivism, the causal theory of reference, and noncircular conceptual analysis.

The fundamental principle of practical reasoning (if there is such a thing) must be a rule which we ought to follow in all our practical reasoning, and which cannot lead to irrational decisions. It must be a rule that it is possible for us to follow directly - that is, without having to follow any other rule of practical reasoning in order to do so. And it must be a basic principle, in the sense that the explanation of why we rationally ought to follow this rule lies purely in the structure of our rational capacities themselves (and not, for example, in empirical evidence that we merely happen to have). This fundamental principle, it is argued, requires that you decide to do something only if the basis of your decision is such that (i) it is rational for you to believe that you have given the matter enough thought, and (ii) your actual deliberation does not warrant the conclusion that the chosen option is definitely worse than some other option that you have considered. A decision formed through reasoning is rational if and only if the agent followed this rule in making the decision. The claim that this is the fundamental principle of practical reasoning conflicts with Hobbesian approaches because it implies that practical reasoning aims not only at satisfying desires, but at forming beliefs about which options are better than others. It conflicts with Kantian approaches because it implies that to think of something as a good thing to do is not just to think of it as a rational thing to choose. This account also shows how to solve some famous controversies surrounding practical reason: the key is to understand how the rationality of concluding that one option is better than another is affected by our desires, our estimates of probabilities, and our moral judgments.