Scientific reasoning is—and ought to be—conducted in accordance with the axioms of probability. This Bayesian view—so called because of the central role it accords to a theorem first proved by Thomas Bayes in the late eighteenth ...

What role, if any, does formal logic play in characterizing epistemically rational belief? Traditionally, belief is seen in a binary way - either one believes a proposition, or one doesn't. Given this picture, it is attractive to impose certain deductive constraints on rational belief: that one's beliefs be logically consistent, and that one believe the logical consequences of one's beliefs. A less popular picture sees belief as a graded phenomenon.

Normative requirements are often overlooked, but they are central features of the normative world. Rationality is often thought to consist in acting for reasons, but following normative requirements is also a major part of rationality. In particular, correct reasoning – both theoretical and practical – is governed by normative requirements rather than by reasons. This article explains the nature of normative requirements, and gives examples of their importance. It also describes mistakes that philosophers have made as a result of confusing (...) normative requirements with reasons. (shrink)

Allow me to rehearse a familiar scenario. We all know that which ends you have has something to do with what you ought to do. If Ronnie is keen on dancing but Bradley can’t stand it, then the fact that there will be dancing at the party tonight affects what Ronnie and Bradley ought to do in different ways. In short, (HI) you ought, if you have the end, to take the means. But now trouble looms: what if you have (...) dreadful, murderous ends? Ought you to take the means to them? Seemingly not. But fortunately, an assumption made by deontic logics1 comes to the rescue. Since ‘‘ought’’, according to this assumption, is a sentential operator, HI must really be ambiguous. It could be read either as (Narrow) You have the end ! O(you take the means) or as (Wide) O(you have the end ! you take the means). Now if Narrow is true, then you really ought to take the means to your murderous ends. But this doesn’t follow from Wide. All that follows from Wide is that you ought to either take the means to these ends or else give them up. Conclusions: (1) Since HI is on some reading true, but Narrow isn’t, Wide is true. (2) Wide accounts for the relationship between your ends and what you ought to do. This elegant scenario repeats itself in many other domains in which it seems like something can have a bearing on what some particular agent ought to do. Does what you know affect what you ought to do? Do your beliefs about what you ought to do affect what you ought to do? Do your promises affect what you ought to do? Do your beliefs affect what you ought to believe? On each of these counts, the intuitive answer is ‘‘yes’’. And so each of these questions leaves something for the moral philosopher or the epistemologist to investigate. On each count, it seems that what we all know, is that (Account) you ought, if p, to do A. But on each count, the Narrow-scope reading of the ‘‘ought’’ in this claim yields unintuitive consequences. So since Account is true, it must be true on the Wide-scope reading.. (shrink)

This paper is a response to ‘Why Be Rational?’ by Niko Kolodny. Kolodny argues that we have no reason to satisfy the requirements of rationality. His argument assumes that these requirements have a logically narrow scope. To see what the question of scope turns on, this comment provides a semantics for ‘requirement’. It shows that requirements of rationality have a wide scope, at least under one sense of ‘requirement’. Consequently Kolodny's conclusion cannot be derived.

Overview of fundamental work in deontic logic.

Several years ago I came across a marvelous little paper in which Hector-Neri Castaneda shows that standard versions of act utilitarian l ism are formally incoherent. I was intrigued by his argument. It had long seemed to me that I had a firm grasp on act utilitarianism. Indeed, it had often seemed to me that it was the clearest and most attractive of normative theories. Yet here was a simple and relatively uncontrover sial argument that showed, with only some trivial (...) assumptions, that the doctrine is virtually unintelligible. The gist of Castaneda's argument is this: suppose we understand act utilitarianism to be the view that an act is obligatory if and only if its utility exceeds that of each alternative. Suppose it is obligatory for a certain person to perform an act with two parts - we can call it 'A & B'. Then, obviously enough, it is also obligatory for this person to perform the parts, A and B. If act utilitarianism were true, we appar ently could infer that the utility of A & B is higher than that of A, and higher than that of B (because A & B is obligatory, and the other acts are alternatives to A & B). (shrink)

Recently, much attention has been paid to ‘rational requirements’ and, especially, to what I call ‘rational requirements of formal coherence as such’. These requirements are satisfied just when our attitudes are formally coherent: for example, when our beliefs do not contradict each other. Nevertheless, these requirements are puzzling. In particular, it is unclear why we should satisfy them. In light of this, I explore the conjecture that there are no requirements of formal coherence. I do so by trying to construct (...) a theory of error for the idea that there are such requirements. (shrink)

Formally-inclined epistemologists often theorize about ideally rational agents--agents who exemplify rational ideals, such as probabilistic coherence, that human beings could never fully realize. This approach can be defended against the well-know worry that abstracting from human cognitive imperfections deprives the approach of interest. But a different worry arises when we ask what an ideal agent should believe about her own cognitive perfection (even an agent who is in fact cognitively perfect might, it would seem, be uncertain of this fact). Consideration (...) of this question reveals an interesting feature of the structure of our epistemic ideals: for agents with limited information, our epistemic ideals turn out to conflict with one another. (shrink)

Bayesian decision theory can be viewed as the core of psychological theory for idealized agents. To get a complete psychological theory for such agents, you have to supplement it with input and output laws. On a Bayesian theory that employs strict conditionalization, the input laws are easy to give. On a Bayesian theory that employs Jeffrey conditionalization, there appears to be a considerable problem with giving the input laws. However, Jeffrey conditionalization can be reformulated so that the problem disappears, and (...) in fact the reformulated version is more natural and easier to work with on independent grounds. (shrink)

Bayesianism is a collection of positions in several related fields, centered on the interpretation of probability as something like degree of belief, as contrasted with relative frequency, or objective chance. However, Bayesianism is far from a unified movement. Bayesians are divided about the nature of the probability functions they discuss; about the normative force of this probability function for ordinary and scientific reasoning and decision making; and about what relation (if any) holds between Bayesian and non-Bayesian concepts.

Niko Kolodny has argued that some (local) rational requirements are narrow-scope requirements. Against this, I argue here that all (local) rational requirements are wide-scope requirements. I present a new objection to the narrow-scope interpretations of the four specific rational requirements which Kolodny considers. His argument for the narrow-scope interpretations of these four requirements rests on a false assumption, that an attitude which puts in place a narrow-scope rational requirement somewhere thereby puts in place a narrow-scope rational requirement everywhere. My argument (...) against Kolodny is analogous to arguments which use holism about reasons to defend moral particularism. (shrink)

Handbook of the History of Logic, vol. 10, eds. Dov Gabbay, Stephan Hartmann, and John Woods, forthcoming.

Bayesian confirmation theory—abbreviated to in these notes—is the predominant approach to confirmation in late twentieth century philosophy of science. It has many critics, but no rival theory can claim anything like the same following. The popularity of the Bayesian approach is due to its flexibility, its apparently effortless handling of various technical problems, the existence of various a priori arguments for its validity, and its injection of subjective and contextual elements into the process of confirmation in just the places where (...) critics of earlier approaches had come to think that subjectivity and sensitivity to context were necessary. (shrink)

Offers a conciliatory solution to one of the central contemporary debates in the theory of rationality, the debate about the proper formulation of rational requirements. Introduces a novel conception of the “symmetry problem” for wide scope rational requirements, and sketches a theory of rational commitment as a response.

Some irrational states can be avoided in more than one way. For example, if you believe that you ought to A you can avoid akrasia by intending to A or by dropping the belief that you ought to A. This supports the claim that some rational requirements are wide-scope. For instance, the requirement against akrasia is a requirement to intend to A or not believe that you ought to A. But some writers object that this Wide-Scope view ignores asymmetries between (...) the different ways of avoiding irrationality. In this paper I defend the Wide-Scope view against recent objections of this sort from Mark Schroeder and Niko Kolodny. I argue that once we are clear about what the Wide-Scope view is committed to—and, importantly, what it is not—we can see that Schroeder and Kolodny’s objections fail. (shrink)

Much contemporary epistemology is informed by a kind of confirmational holism, and a consequent rejection of the assumption that all confirmation rests on experiential certainties. Another prominent theme is that belief comes in degrees, and that rationality requires apportioning one's degrees of belief reasonably. Bayesian confirmation models based on Jeffrey Conditionalization attempt to bring together these two appealing strands. I argue, however, that these models cannot account for a certain aspect of confirmation that would be accounted for in any adequate (...) holistic confirmation theory. I then survey the prospects for constructing a formal epistemology that better accommodates holistic insights. (shrink)

It often seems that what one ought to do depends on what contingent ends one has adopted and the means to pursuing them. Imagine, for example, that you are applying for jobs, and a particularly attractive one comes your way. It offers excellent colleagues in a desirable location, the pay is good, and acquiring a job like this is one of your ends. If practicing your job talk is a means to getting the job, the following seems true: (1) If (...) you want1 to get the job, then you ought to practice your job talk. Let us call conditional ought sentences that purport to express an end in the antecedent and a means to the end in the consequent end-given oughts. Some end-given oughts run into the problem of detachment; i.e., some end-given oughts seem true, and yet we do not think the consequent by itself, detached from the conditional, is true even if the antecedent is true. Consider a case where you want revenge on Bill for some slight offense. You happen to have the opportunity to poison Bill’s drink while he is away, which is the only thing that would lead to his demise. What of: (2) If you want to kill Bill, then you ought to poison his drink. (2) runs up against the problem of detachment because of the following modus ponens argument: • If you want to kill Bill, then you ought to poison his drink. • You want to kill Bill. • Therefore, you ought to poison his drink. In fact, you ought not poison Bill’s drink. You ought to avoid him and seek counseling. (shrink)

Instrumental rationality prohibits one from being in the following state: intending to pass a test, not intending to study, and believing one must intend to study if one is to pass. One could escape from this incoherent state in three ways: by intending to study, by not intending to pass, or by giving up one’s instrumental belief. However, not all of these ways of proceeding seem equally rational: giving up one’s instrumental belief seems less rational than giving up an end, (...) which itself seems less rational than intending the means. I consider whether, as some philosophers allege, these “asymmetries” pose a problem for the wide-scope formulation of instrumental rationality. I argue that they do not. I also present an argument in favor of the wide-scope formulation. The arguments employed here in defense of the wide-scope formulation of instrumental rationality can also be employed in defense of the wide-scope formulations of other rational requirements. (shrink)

You are irrational when you are akratic. On this point most agree. Despite this agreement, there is a tremendous amount of disagreement about what the correct explanation of this data is. Narrow-scopers think that the correct explanation is that you are violating a narrow-scope conditional requirement. You lack an intention to x that you are required to have given the fact that you believe you ought to x. Wide-scopers disagree. They think that a conditional you are required to make true (...) is false. You aren’t required to have any particular attitudes. You’re just required to intend to x or not believe you ought to x. Wide-scope accounts are symmetrical insofar as they predict that you are complying with the relevant requirement just so long as the relevant conditional is true. Some narrow-scopers object to this symmetry. However, there is disagreement about why the symmetry is objectionable. This has led wide-scopers to defend their view against a number of different symmetry objections. I think their defenses in the face of these objections are, on the whole, plausible. Unfortunately for them, they aren’t defending their view against the best version of the objection. In this paper I will show that there is a symmetry objection to wide-scope accounts that both hasn’t been responded to and is a serious problem for wide-scope accounts. Moreover, my version of the objection will allow us to see that there is at least one narrow-scope view that has been seriously underappreciated in the literature. (shrink)

I argue that given standard deontic logic, wide-scope rational requirements entail narrow-scope rational requirements. In particular, the widely-embraced Enkratic Principle entails that if a particular combination of attitudes is rationally forbidden, it is also rationally forbidden to believe that that combination of attitudes is required.

You are irrational when you are akratic. On this point most agree. Despite this agreement, there is a tremendous amount of disagreement about what the correct explanation of this data is. Narrow-scopers think that the correct explanation is that you are violating a narrow-scope conditional requirement. You lack an intention to x that you are required to have given the fact that you believe you ought to x. Wide-scopers disagree. They think that a conditional you are required to make true (...) is false. You aren’t required to have any particular attitudes. You’re just required to intend to x or not believe you ought to x. Wide-scope accounts are symmetrical insofar as they predict that you are complying with the relevant requirement just so long as the relevant conditional is true. Some narrow-scopers object to this symmetry. However, there is disagreement about why the symmetry is objectionable. This has led wide-scopers to defend their view against a number of different symmetry objections. I think their defenses in the face of these objections are, on the whole, plausible. Unfortunately for them, they aren’t defending their view against the best version of the objection. In this paper I will show that there is a symmetry objection to wide-scope accounts that both hasn’t been responded to and is a serious problem for wide-scope accounts. Moreover, my version of the objection will allow us to see that there is at least one narrow-scope view that has been seriously underappreciated in the literature. (shrink)

This article discusses some of the ways in which natural language can express modal information – information which is, to a first approximation, about what could be or must be the case, as opposed to being about what actually is the case. It motivates, explains, and raises problems for Angelika Kratzer's influential theory of modal auxiliaries, and introduces a new approach to one important debate about the relationships between modality, evidentiality, context change, and imperative force.

This volume brings together Nicholas Wolterstorff's essays on epistemology written between 1983 and 2008.