The paper investigates what type of motivation can be given for adopting a knowledge-based decision theory. KBDT seems to have several advantages over competing theories of rationality. It is commonly argued that this theory would naturally fit with the intuitive idea that being rational is doing what we take to be best given what we know, an idea often supported by appeal to ordinary folk appraisals. Moreover, KBDT seems to strike a perfect balance between the problematic extremes of subjectivist and (...) objectivist decision theory. We argue that these alleged advantages do not stand up to a closer scrutiny: KBDT inherits the same kinds of problems as alternative decision theoretic frameworks but doesn’t retain any of the respective advantages. Moreover, differently from other knowledge-action principles advanced in the literature, KBDT cannot fully explain the intuitive connections between knowledge and rational action. We conclude that the most serious challenge for knowledge-based decision theorists is to provide a substantive rationale for the adoption of such a view. (shrink)

Contextualists and Subject Sensitive Invariantists often cite the knowledge norm of assertion as part of their argument. They claim that the knowledge norms in conjunction with our intuitions about when a subject is properly asserting in low or high stakes contexts provides strong evidence that what counts as knowledge depends on practical factors. In this paper, I present new data to suggest they are mistaken in the way they think about cases involving high and low stakes and I show how (...) insensitive invariantists can explain the data. I exploit recent work done on the distinction between flouting a norm and being blamed for that violation to formulate a rigorous theory of rational expected blameworthiness that allows insensitive invariantists to explain the data cited. (shrink)

The world is said to contain crystal balls whenever the present carries news of the as-yet-undetermined parts of the future. Many philosophers believe that crystal balls are metaphysically possible. In this essay, I argue that they are not. Whether crystal balls are possible matters, for at least two reasons. The first is epistemological. According to a simple, user-friendly chance norm for credence, which I call the Present Principle, agents are rationally required to conform their credences to their expectations of the (...) present chances, deferring to the present chances as they would to an expert. I would like to defend the Present Principle since its truth would do much to simplify the relation between chance and credence. But the Present Principle is counterexample-free, and hence defensible, only if crystal balls are impossible. The second reason is decision-theoretic. The problem of crystal balls is one of the main objections to causal decision theory. But crystal ball cases can be counterexample to causal decision theory only if crystal balls are possible, and, as I argue, crystal balls are not possible. (shrink)

A knowledge-based decision theory faces what has been called the prodigality problem : given that many propositions are assigned probability 1, agents will be inclined to risk everything when betting on propositions which are known. In order to undo probability 1 assignments in high risk situations, the paper develops a theory which systematically connects higher level goods with higher-order knowledge.

The current debate about peer disagreement has so far mainly focused on the question of whether peer disagreements provide genuine counterevidence to which we should respond by revising our credences. By contrast, comparatively little attention has been devoted to the question by which process, if any, such revision should be brought about. The standard assumption is that we update our credences by conditionalizing on the evidence that peer disagreements provide. In this paper, we argue that non-dogmatist views have good reasons (...) to reject conditionalization. Instead, peer disagreements should be understood to call for a revision of our prior conditional probabilities: rather than merely adding to our original evidence, they pose a challenge to the thought that we have properly assessed the probative force of our original evidence. (shrink)

Are all epistemic notions – including evidence and rational credence – sensitive to practical considerations? A number of philosophers have argued that the answer must be ‘No’, since otherwise rational agents would be susceptible to diachronic Dutch books. After unpacking this challenge, I show how it can be resisted by appealing to an analogy between shifting stakes and memory loss. The upshot: pervasive epistemic shiftiness may be tenable after all.

The threshold view says that a person forms an outright belief P if and only if her credence for P reaches a certain threshold. Using computer simulations, I compare different versions of the threshold view to understand how they perform under time pressure in decision problems. The results illuminate the strengths and weaknesses of the various cognitive strategies in different decision contexts. A threshold view that performs well across diverse contexts is likely to be a cognitively flexible and context-dependent fusion (...) of several of the existing theories. The results of the simulations also cast doubts on the possibility of a threshold view that is both simple enough to streamline our reasoning while also allowing us to form good action-guiding beliefs. (shrink)

According to a suggestion by Williamson, outright belief comes in degrees: one has a high/low degree of belief iff one is willing to rely on the content of one’s belief in high/low-stakes practical reasoning. This paper develops an epistemic norm for degrees of outright belief so construed. Starting from the assumption that outright belief aims at knowledge, it is argued that degrees of belief aim at various levels of strong knowledge, that is, knowledge which satisfies particularly high epistemic standards. This (...) account is contrasted with and shown to be superior to an alternative proposal according to which higher degrees of outright belief aim at higher-order knowledge. In an “Appendix”, it is indicated that the logic of degrees of outright belief is closely linked to ranking theory. (shrink)

It is often thought that bets on the truth of known propositions become irrational if the losing costs are high enough. This is typically taken to count against the view that knowledge involves assigning credence 1. I argue that the irrationality of such extreme bets can be explained by considering the interactions between the agent and the bookmaker. More specifically, the agent’s epistemic perspective is altered by the fact that the bookmaker proposes that unusual type of bet. Among other things, (...) being willing to offer a bet with unnecessarily harmful losing costs is likely to undermine the baseline level of trustworthiness required for it to be rational to engage in betting exchanges. This sort of explanation does not require granting either that we assign credence lower than 1 to known propositions or that knowledge is sensitive to practical stakes. Moreover, I show that, in our ordinary lives, we frequently perform actions that we know would be disastrous if certain conditions did not obtain. This behaviour can be seen as a form of implicit extreme betting and, nevertheless, it is often rational. (shrink)