How much does rationality constrain what we should believe on the basis of our evidence? According to this book, not very much. For most people and most bodies of evidence, there is a wide range of beliefs that rationality permits them to have in response to that evidence. The argument, which takes inspiration from William James' ideas in 'The Will to Believe', proceeds from two premises. The first is a theory about the basis of epistemic rationality. It's called epistemic utility theory, and it says that what it is epistemically rational for you to believe is what it would be rational for you to choose if you were given the chance to pick your beliefs and, when picking them, you were to care only about their epistemic value. So, to say which beliefs are permitted, we must say how to measure epistemic value, and which decision rule to use when picking your beliefs. The second premise is a claim about attitudes to epistemic risk, and it says that rationality permits many different such attitudes. These attitudes can show up in epistemic utility theory in two ways: in the way you measure epistemic value; and in the decision rule you use to pick beliefs. This book explores the latter. The result is permissivism about epistemic rationality: different attitudes to epistemic risk lead to different choices of prior beliefs; given most bodies of evidence, different priors lead to different posteriors; and even once we fix your attitudes to epistemic risk, if they are at all risk-inclined, there is a range of different priors and therefore different posteriors they permit.

How much does rationality constrain what we should believe on the basis of our evidence? According to this book, not very much. For most people and most bodies of evidence, there is a wide range of beliefs that rationality permits them to have in response to that evidence. The argument, which takes inspiration from William James' ideas in 'The Will to Believe', proceeds from two premises. The first is a theory about the basis of epistemic rationality. It's called epistemic utility theory, and it says that what it is epistemically rational for you to believe is what it would be rational for you to choose if you were given the chance to pick your beliefs and, when picking them, you were to care only about their epistemic value. So, to say which beliefs are permitted, we must say how to measure epistemic value, and which decision rule to use when picking your beliefs. The second premise is a claim about attitudes to epistemic risk, and it says that rationality permits many different such attitudes. These attitudes can show up in epistemic utility theory in two ways: in the way you measure epistemic value; and in the decision rule you use to pick beliefs. This book explores the latter. The result is permissivism about epistemic rationality: different attitudes to epistemic risk lead to different choices of prior beliefs; given most bodies of evidence, different priors lead to different posteriors; and even once we fix your attitudes to epistemic risk, if they are at all risk-inclined, there is a range of different priors and therefore different posteriors they permit.

Action theorists and formal epistemologists often pursue parallel inquiries regarding rationality, with the former focused on practical rationality, and the latter focused on theoretical rationality. In both fields, there is currently a strong interest in exploring rationality in relation to time. This exploration raises questions about the rationality of certain patterns over time. For example, it raises questions about the rational permissibility of certain patterns of intention; similarly, it raises questions about the rational permissibility of certain patterns of belief. While the action-theoretic and epistemic questions raised are closely related, advances in one field are not always processed by the other. This volume brings together contributions by scholars in action theory and formal epistemology working on questions regarding rationality and time so that researchers in these overlapping fields can profit from each other’s insights. This book was originally published as a special issue of the Canadian Journal of Philosophy.

Lara Buchak sets out a new account of rational decision-making in the face of risk. She argues that the orthodox view (expected utility theory) is too narrow, and suggests an alternative, more permissive theory: one that allows individuals to pay attention to the worst-case or best-case scenario, and vindicates the ordinary decision-maker.

This book gives a general theory of rational belief. Although it can be read by itself, is a sequel to the author's previous book The Value of Rationality (Oxford, 2017). It takes the general conception of rationality that was defended in that earlier book, and combines it with an account of the varieties of belief, and of what it is for these beliefs to count as "correct", to develop an account of what it is for beliefs to count as rational. According to this account, rationality comes in degrees: the degree to which one's beliefs counts as rational is determined by their distance from a corresponding probability function - where this distance is measured by those beliefs' "expected degree of incorrectness" according to the probability function; the account also involves an explanation of what determines exactly which probability function plays this role in each case, and of why this probability function should play this role. In developing and defending this account, new light is shed on several central epistemological issues. These issues include: the distinction between propositional and doxastic justification; the debates between internalism and externalism, and between foundationalism and coherentism; the significance - or lack of it - of the notion of 'evidence'; the relationship between credences, full belief, inference, and suspension of judgment; the nature of the kind of possibility that is presupposed by the relevant sort of probability; and whether rationality is "diachronic" - so that the beliefs that it is rational for us to have now depend, in part, on the beliefs that we held in the past. Finally, some suggestions are made about how this theory bears on a range of further topics, including the defeasibility of inference, scepticism, and the analysis of knowledge.

What we value, like, endorse, want, and prefer changes over the course of our lives, sometimes as a result of decisions we make--such as when we choose to become a parent or move to a new country--and sometimes as a result of forces beyond our control--such as when our political views change as we grow older. This poses a problem for any theory of how we ought to make decisions. Which values and preferences should we appeal to when we are making our decisions? Our current values? Our past ones? Our future ones? Or some amalgamation of all them? But if that, which amalgamation? In Choosing for Changing Selves, Richard Pettigrew presents a theory of rational decision making for agents who recognise that their values will change over time and whose decisions will affect those future times.

Good decisions account for risks. For example, the risk of an accident while driving in the rain makes a reasonable driver decide to slow down. While risk is a large topic in theoretical disciplines such as economics and psychology, as well as in practical disciplines such as medicine and finance, philosophy has a unique contribution to make in developing a normative theory of risk that states what risk is, and to what extent our responses to it are rational. Weirich here develops a philosophical theory of the rationality of responses to risk. He first distinguishes two types of risk: first, a chance of a bad event, and second, an act's risk in relation to its possible outcomes. He argues that this distinction has normative significance in the sense that one's attitudes towards these types of risks - and how one acts on them - are governed by different general principles of rationality. Consequently, a comprehensive account of risk must not only characterize rational responses to risk but also explain why these responses are rational. Weirich explains how, for a rational ideal agent, the expected utilities of the acts available in a decision problem explain the agent's preferences among the acts. As a result, maximizing expected utility is just following preferences among the acts. His view takes an act's expected utility, not just as a feature of a representation of preferences among acts, but also as a factor in the explanation of preferences among acts. The book's precise formulation of general standards of rationality for attitudes and for acts, and its rigorous argumentation for these standards, make it philosophical; but while mainly of interest to philosophers, its broader arguments will contribute to the conceptual foundations of studies of risk in all disciplines that study it.