Ralph Wedgwood

Gandalf's solution to the Newcomb problem

This article proposes a new theory of rational decision, distinct from both causal decision theory (CDT) and evidential decision theory (EDT). First, some intuitive counterexamples to CDT and EDT are presented. Then the motivation for the new theory is given: the correct theory of rational decision will resemble CDT in that it will not be sensitive to any comparisons of absolute levels of value across different states of nature, but only to comparisons of the differences in value between the available options within states of nature; however, the correct theory will also resemble EDT in that it will rely on conditional probabilities (not unconditional probabilities). The new theory gives a prominent role to the notion of a “benchmark” for each state of nature, by comparison with which the value of the available options in that state of nature are measured, and so it has been called the Benchmark Theory (BT). It is argued that BT gives the right verdict on the cases that seem to be counterexamples to CDT and EDT. Finally, some objections to BT are considered and answered.

The Price of Non-reductive Moral Realism

Non-reductive moral realism is the view that there are moral properties which cannot be reduced to natural properties. If moral properties exist, it is plausible that they strongly supervene on non-moral properties- more specifically, on mental, social, and biological properties. There may also be good reasons for thinking that moral properties are irreducible. However, strong supervenience and irreducibility seem incompatible. Strong supervenience entails that there is an enormous number of modal truths (specifically, truths about exactly which non-moral properties necessitate which moral properties); and all these modal truths must be explained. If these modal truths can all be explained, then it must be a fundamental truth about the essence of each moral property that the moral property is necessarily equivalent to some property that can be specified purely in mental, social and biological terms; and this fundamental truth appears to be a reduction of the moral property in question. The best way to resist this argument is by resorting to the claim that mental and social properties are not, strictly speaking, natural properties, but are instead properties that can only be analysed in partly normative terms. Acceptance of that claim is the price of non-reductive moral realism.

Practical Reason and Desire

According to the Humean Theory of Practical Reason (HTPR), every rational action must serve some desire that the agent has (or at least would have if she rationally performed that action)—where this desire is, as I shall put it, a ‘contingent desire’, a desire that the agent is not in any way rationally required to have. Humeans typically argue for the HTPR on the basis of the following two premisses: first, the Humean Theory of Motivation (HTM), the view that all motivation of action has such contingent desire ‘at its source’; and second, the Internalism Requirement (IR), the view that ‘reasons must be capable of motivating’. This argument for the HTPR is familiar, but it has rarely been stated with sufficient precision. In this paper, I shall give a precise statement of this argument and of the HTPR. 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 support the HTPR.

Primitively Rational Belief-Forming Processes

One approach to understanding “reasons”—including both reasons for action and reasons for belief—postulates a fundamental connection between reasons and reasoning. According to this approach, there is a reason for you to φ—where φ-ing could be either an action (such as writing a letter) or an attitude (such as believing that it is snowing)—if and only if there is a possible process of sound or rational reasoning that could take you from your current state of mind to your rationally φ-ing. This approach is familiar in discussions of reasons for action. As Bernard Williams (1995, 35) put it, for there to be a reason for you to φ, there must be a “sound deliberative route” that leads from your current state of mind to your being motivated to φ. Presumably, Williams’s reference to “a sound deliberative route” comes to more or less the same thing as my own terminology of a “possible process of rational reasoning”. 1

The Fundamental Principle of Practical Reasoning

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...

Must rational intentions maximize utility

Suppose that it is rational to choose or intend a course of action if and only if the course of action maximizes some sort of expectation of some sort of value. What sort of value should this definition appeal to? According to an influential neo-Humean view, the answer is “Utility”, where utility is defined as a measure of subjective preference. According to a rival neo-Aristotelian view, the answer is “Choiceworthiness”, where choiceworthiness is an irreducibly normative notion of a course of action that is good in a certain way. The neo-Human view requires preferences to be measurable by means of a utility function. Various interpretations of what exactly a “preference” is are explored, to see if there is any interpretation that supports the claim that a rational agent’s “preferences” must satisfy the “axioms” that are necessary for them to be measurable in this way. It is argued that the only interpretation that supports the idea that the rational agent’s preferences must meet these axioms interprets “preferences” as a kind of value-judgment. But this turns out to be version of the neo-Aristotelian view, rather than the neo-Humean view. Rational intentions maximize expected choiceworthiness, not expected utility.

The internalist virtue theory of knowledge

Here is a definition of knowledge: for you to know a proposition p is for you to have an outright belief in p that is correct precisely because it manifests the virtue of rationality. This definition resembles Ernest Sosa’s “virtue theory”, except that (a) on this definition, the only virtue that must be manifested (at least to some degree) in all instances of knowledge is rationality, and (b) no reductive account of rationality is attempted—rationality is assumed to be an irreducibly normative notion. This definition is compatible with “internalism” about rationality, and with a form of “pragmatic encroachment” on the conditions of rational outright belief. An interpretation is given of this definition, and especially of the sense of ’because’ that it involves. On this interpretation, this definition entails that both safety and adherence are necessary conditions on knowledge; it supports a kind of contextualism about terms like ‘knowledge’; and it provides resources to defend safety, adherence, and contextualism, against some recent objections.