First published in 1982, Ellery Eells' original work on rational decision making had extensive implications for probability theorists, economists, statisticians and psychologists concerned with decision making and the employment of Bayesian principles. His analysis of the philosophical and psychological significance of Bayesian decision theories, causal decision theories and Newcomb's paradox continues to be influential in philosophy of science. His book is now revived for a new generation of readers and presented in a fresh twenty-first-century series livery, including a specially (...) commissioned preface written by Brian Skyrms, illuminating its continuing importance and relevance to philosophical enquiry. (shrink)

Predictable polarization is everywhere: we can often predict how people’s opinions, including our own, will shift over time. Extant theories either neglect the fact that we can predict our own polarization, or explain it through irrational mechanisms. They needn’t. Empirical studies suggest that polarization is predictable when evidence is ambiguous, that is, when the rational response is not obvious. I show how Bayesians should model such ambiguity and then prove that—assuming rational updates are those which obey the value (...) of evidence—ambiguity is necessary and sufficient for the rationality of predictable polarization. The main theoretical result is that there can be a series of such updates, each of which is individually expected to make you more accurate, but which together will predictably polarize you. Polarization results from asymmetric increases in accuracy. This mechanism is not only theoretically possible, but empirically plausible. I argue that cognitive search—searching a cognitively accessible space for a particular item—often yields asymmetrically ambiguous evidence, I present an experiment supporting its polarizing effects, and I use simulations to show how it can explain two of the core causes of polarization: confirmation bias and the group polarization effect. (shrink)

Commentators typically neglect the distinct nature and role of hope in Kant’s system, and simply lump it together with the sort of Belief that arises from the moral proof. Kant himself is not entirely innocent of the conflation. Here I argue, however, that from a conceptual as well as a textual point of view, hope should be regarded as a different kind of attitude. It is an attitude that we can rationally adopt toward some of the doctrines that are not (...) able to be proved from within the bounds of mere reason – either theoretical or practical. This does not mean that hope is unconstrained; there are rational limits, as we shall see. In fact one of my central claims here is that a crucial difference between knowledge, rational Belief, and rational hope is that they are governed by different modal constraints; section II discusses those constraints and the kind of modality involved. In section III, I return to Religion and offer what I take to be Kant’s account of the main objects of rational hope in that text – namely, “alleged outer experiences (miracles)”;a “supposed inner experience(effect of grace)”;and a future collective experience (the construction of a truly ethical society). (shrink)

It is valuable for inquiry to have researchers who are committed advocates of their own theories. However, in light of pervasive disagreement, such a commitment is not well explained by the idea that researchers believe their theories. Instead, this commitment, the rational attitude to take toward one’s favored theory during the course of inquiry, is what I call endorsement. Endorsement is a doxastic attitude, but one which is governed by a different type of epistemic rationality. This inclusive epistemic rationality (...) is sensitive to reasons beyond those to think the particular proposition in question is true. Instead, it includes extrinsic epistemic reasons, which concern the health of inquiry more generally. Such extrinsic reasons include the distribution of cognitive labor that a researcher will contribute to by endorsing a particular theory. Recognizing endorsement and inclusive epistemic rationality thus allows us to smooth a tension between individual rationality and collective rationality. It does so by showing how it can be epistemically rational to endorse a theory on the basis of the way this endorsement will benefit collective inquiry. I provide a decision theoretic treatment for inclusive epistemic rationality and endorsement which illustrates how this can be accomplished. (shrink)

Closure for justification is the claim that thinkers are justified in believing the logical consequences of their justified beliefs, at least when those consequences are competently deduced. Many have found this principle to be very plausible. Even more attractive is the special case of Closure known as Single-Premise Closure. In this paper, I present a challenge to Single-Premise Closure. The challenge is based on the phenomenon of rational self-doubt – it can be rational to be less than fully (...) confident in one's beliefs and patterns of reasoning. In rough outline, the argument is as follows: Consider a thinker who deduces a conclusion from a justified initial premise via an incredibly long sequence of small competent deductions. Surely, such a thinker should suspect that he has made a mistake somewhere. And surely, given this, he should not believe the conclusion of the deduction even though he has a justified belief in the initial premise. (shrink)

Game theory has proved a useful tool in the study of simple economic models. However, numerous foundational issues remain unresolved. The situation is particularly confusing in respect of the non-cooperative analysis of games with some dynamic structure in which the choice of one move or another during the play of the game may convey valuable information to the other players. Without pausing for breath, it is easy to name at least 10 rival equilibrium notions for which a serious case can (...) be made that here is the “right” solution concept for such games. (shrink)

It is widely held that Bayesian decision theory is the final word on how a rational person should make decisions. However, Leonard Savage--the inventor of Bayesian decision theory--argued that it would be ridiculous to use his theory outside the kind of small world in which it is always possible to "look before you leap." If taken seriously, this view makes Bayesian decision theory inappropriate for the large worlds of scientific discovery and macroeconomic enterprise. When is it correct to use (...) Bayesian decision theory--and when does it need to be modified? Using a minimum of mathematics, Rational Decisions clearly explains the foundations of Bayesian decision theory and shows why Savage restricted the theory's application to small worlds. The book is a wide-ranging exploration of standard theories of choice and belief under risk and uncertainty. Ken Binmore discusses the various philosophical attitudes related to the nature of probability and offers resolutions to paradoxes believed to hinder further progress. In arguing that the Bayesian approach to knowledge is inadequate in a large world, Binmore proposes an extension to Bayesian decision theory--allowing the idea of a mixed strategy in game theory to be expanded to a larger set of what Binmore refers to as "muddled" strategies. Written by one of the world's leading game theorists, Rational Decisions is the touchstone for anyone needing a concise, accessible, and expert view on Bayesian decision making. (shrink)

This is a paperback edition of a major contribution to the field, first published in hard covers in 1977. The book outlines a general theory of rational behaviour consisting of individual decision theory, ethics, and game theory as its main branches. Decision theory deals with a rational pursuit of individual utility; ethics with a rational pursuit of the common interests of society; and game theory with an interaction of two or more rational individuals, each pursuing his (...) own interests in a rational manner. (shrink)

According to Bayesian epistemology, rational learning from experience is consistent learning, that is learning should incorporate new information consistently into one's old system of beliefs. Simon M. Huttegger argues that this core idea can be transferred to situations where the learner's informational inputs are much more limited than Bayesianism assumes, thereby significantly expanding the reach of a Bayesian type of epistemology. What results from this is a unified account of probabilistic learning in the tradition of Richard Jeffrey's 'radical probabilism'. (...) Along the way, Huttegger addresses a number of debates in epistemology and the philosophy of science, including the status of prior probabilities, whether Bayes' rule is the only legitimate form of learning from experience, and whether rational agents can have sustained disagreements. His book will be of interest to students and scholars of epistemology, of game and decision theory, and of cognitive, economic, and computer sciences. (shrink)

SummaryNeither an infant one week old nor a snail is a rational creature. If the infant survives long enough, he will probably become rational, while this is not true of the snail. If we like, we may say of the infant from the start that he is a rational creature because he will probably become rational if he survives, or because he belongs to a species with this capacity. Whichever way we talk, there remains the difference, (...) with respect to rationality, between the infant and the snail on one hand, and the normal adult person on the other; this difference is discussed here.The difference consists, it is argued, in the having of propositional attitudes such as belief, desire, intention and shame. This raises the question how to tell when a creature has propositional attitudes; snails, we may agree, do not, but how about dogs or chimpanzees? The question is not empirical; the question is what sort of empirical evidence is relevant to deciding when a creature has propositional attitudes.It is next contended that language is a necessary concomitant of any of the propositional attitudes. This idea is not new, but there seem to be few arguments in its favor in the literature; one is attempted here.Crucial to the considerations advanced is the idea that belief depends on having the concept of objective truth, and that this comes only with language.RéuméNi un bébé d'une semaine, ni un serpent ne sont des créatures rationnelles. Si le bébé survit assez longtemps, il deviendra probablement rationnel, mais ce n'est pas vrai pour le serpent. Sil'on veut, on peut dire d'emblee du bébé qu'il est une créature rationnelle parce qu'il le deviendra s'il survit ou parce qu'il appartient à une espèce qui possède cette faculté. Quoi qu'on dise, la différence subsiste, en ce qui concerné la rationalité, entre le bébé et le serpent d'une part, la per‐sonne adulte normale de lcar;autre, et c'est cette différence qui sera discutée ici.La différence consiste, selon l'auteur, en une capacityé d'avoir des attitudes propositionnelles telles que la croyance, le désir, l'intention et la honte. Ceci pose la question de savoir quand on peut dire qu'une créature a des attitudes propositionnelles; on peut se mettre d'accord sur le fait que les serpents n'en ont pas, mais qu'en est‐il des chiens et des chimpanzés? La question n'est pas empirique, elle est de savoir quelle donnée empirique va décider si oui ou non une créature a des attitudes propositionnelles.L'auteur prétend que les attitudes propositionnelles s'accompagnent nécessairement du langage. Cette idèe n'est pas nouvelle, mais il semble qu'il y a peu d'arguments qui la soutiennent dans la littérature. On en trouvera un ici, où l'on montre qu'un élément crucial de a croyance dépend de l'acquisition du concept de vérité objective, qui ne se développe qu'avec le langage.ZusammenfassungWeder ein eine Woche altes Kind noch eine Schlange sind rationale Wesen. Wenn das Kind lange genug überlebt, wird es sich wahrscheinlich zu einem vernünftigen Wesen entwickeln, wäh‐rend das für die Schlange nicht zutrifft. Wenn wir wollen, können wir vom Kind sagen, dass es von Anfang an cin rationales Wesen ist, weil es im Fallc des Ubcrlebens vernünftig werden wird oder weil es zu einer Spezies mit dieser Fähigkeit gehört. Wie auch immer wir das ausdrücken, bleibt bezüglich der Rationalität der Unterschied zwischen dem Kind und der Schlange einerseits und der erwachsenen Person andererseits zurück. Dieser Unterschied wird hier diskutiert.Es wird argumentiert, dass der Unterschied in der Fähigkeit besteht, psychologische Haltun‐gen wie Glauben, Begierden, Absichten und Scham zu haben. Damit erhebt sich die Frage, wie man entscheiden kann, wann ein Wesen solchc Einstellungcn hat; Schlangen, wird man zugeben, haben keine; wie steht es aber mit Hunden Oder Schimpansen? Die Frage ist keine empirische, sondern betrifft die Frage, welche Art von empirischen Belegen für den Entscheid relevant ist, ob ein Wesen derartige Einstellungen hat.Es wird die These aufgestellt, dass Sprachen ein notwendiger Begleitumstand einer jeglichen propositionalen Haltung ist. Der Gedanke ist zwar nicht neu, aber es finden sich wenige Argu‐mente zu seiner Stützung in der Literatur; eines wird hier ausgeführt.Entscheidend für die vorgelegten Betrachtungen ist die Auffassung, wonach Glaube vom Begriff der objektiven Wahrheit abhängt, und dieser kommt erst mit der Sprache. (shrink)

Whereas Bayesians have proposed norms such as probabilism, which requires immediate and permanent certainty in all logical truths, I propose a framework on which credences, including credences in logical truths, are rational because they are based on reasoning that follows plausible rules for the adoption of credences. I argue that my proposed framework has many virtues. In particular, it resolves the problem of logical omniscience.

In past years, the traditional Bayesian theory of rational decision making, based on subjective calculations of expected utility, has faced powerful attack from philosophers such as David Lewis and Brian Skyrms, who advance an alternative causal decision theory. The test they present for the Bayesian is exemplified in the decision problem known as 'Newcomb's paradox' and in related decision problems and is held to support the prescriptions of the causal theory. As well as his conclusions, the concepts and methods (...) of Professor Eells introduces in the course of his analyses have extensive implications, not solely for probability theorists narrowly conceived, but for economists, statisticians and psychologists concerned with decision making and the employment of Bayesian principles. They and their students will, in addition, find the early chapters of great use as a background and introduction to the subject as a whole. (shrink)

It is widely held that Bayesian decision theory is the final word on how a rational person should make decisions. However, Leonard Savage--the inventor of Bayesian decision theory--argued that it would be ridiculous to use his theory outside the kind of small world in which it is always possible to "look before you leap." If taken seriously, this view makes Bayesian decision theory inappropriate for the large worlds of scientific discovery and macroeconomic enterprise. When is it correct to use (...) Bayesian decision theory--and when does it need to be modified? Using a minimum of mathematics, Rational Decisions clearly explains the foundations of Bayesian decision theory and shows why Savage restricted the theory's application to small worlds. The book is a wide-ranging exploration of standard theories of choice and belief under risk and uncertainty. Ken Binmore discusses the various philosophical attitudes related to the nature of probability and offers resolutions to paradoxes believed to hinder further progress. In arguing that the Bayesian approach to knowledge is inadequate in a large world, Binmore proposes an extension to Bayesian decision theory--allowing the idea of a mixed strategy in game theory to be expanded to a larger set of what Binmore refers to as "muddled" strategies. Written by one of the world's leading game theorists, Rational Decisions is the touchstone for anyone needing a concise, accessible, and expert view on Bayesian decision making. (shrink)

Scott Sturgeon presents an original account of mental states and their dynamics. He develops a detailed story of coarse- and fine-grained mental states, a novel perspective on how they fit together, an engaging theory of the rational transitions between them, and a fresh view of how formal methods can advance our understanding in this area. In doing so, he addresses a deep four-way divide in literature on epistemic rationality. Formal epistemology is done in specialized languages--often seeming a lot more (...) like mathematics than Plato--and so can alienate philosophers who are drawn to more traditional work on thought experiments in epistemic rationality. Conversely, informal epistemology appears to be a lot more like Plato than mathematics and, as such, it tends to deter philosophers drawn to formal models of the phenomena. Similarly, the epistemology of coarse-grained states boils down everything to a discussion of rational belief--making the area appear a lot more like foundations of knowledge than anything useful for the theory rational decision, such as decision-making under uncertainty. The Rational Mind unifies work in all of these areas for the first time. (shrink)

Public discussions of political and social issues are often characterized by deep and persistent polarization. In social psychology, it’s standard to treat belief polarization as the product of epistemic irrationality. In contrast, we argue that the persistent disagreement that grounds political and social polarization can be produced by epistemically rational agents, when those agents have limited cognitive resources. Using an agent-based model of group deliberation, we show that groups of deliberating agents using coherence-based strategies for managing their limited resources (...) tend to polarize into different subgroups. We argue that using that strategy is epistemically rational for limited agents. So even though group polarization looks like it must be the product of human irrationality, polarization can be the result of fully rational deliberation with natural human limitations. (shrink)

Probabilism is the view that a rational agent's credences should always be probabilistically coherent. It has been argued that Probabilism follows, given the assumption that an epistemically rational agent ought to try to have credences that represent the world as accurately as possible. The key claim in this argument is that the goal of representing the world as accurately as possible is best served by having credences that are probabilistically coherent. This essay shows that this claim is false. (...) In certain cases, the goal of having accurate credences is best served by being probabilistically incoherent. Assuming that an epistemically rational agent ought to try to have credences that are as accurate as possible, it follows that in certain cases a rational agent ought to have probabilistically incoherent credences. (shrink)

A theory of rational belief should get the cases right. It should also reach its verdicts using the right theoretical assumptions. Leading theories seem to predict the wrong things. With only one exception, they don't accommodate principles that we should use to explain these verdicts. We offer a theory of rational belief that combines an attractive picture of epistemic desirability with plausible principles connecting desirability to rationality. On our view, it's rational to believe when it's sufficiently likely (...) that you'd know because believing when it's sufficiently likely that you'd know minimises expected objective epistemic undesirability. (shrink)

Belief polarization is said to occur when two people respond to the same evidence by updating their beliefs in opposite directions. This response is considered to be “irrational” because it involves contrary updating, a form of belief updating that appears to violate normatively optimal responding, as for example dictated by Bayes' theorem. In light of much evidence that people are capable of normatively optimal behavior, belief polarization presents a puzzling exception. We show that Bayesian networks, or Bayes nets, can simulate (...) rational belief updating. When fit to experimental data, Bayes nets can help identify the factors that contribute to polarization. We present a study into belief updating concerning the reality of climate change in response to information about the scientific consensus on anthropogenic global warming. The study used representative samples of Australian and U.S. participants. Among Australians, consensus information partially neutralized the influence of worldview, with free-market supporters showing a greater increase in acceptance of human-caused global warming relative to free-market opponents. In contrast, while consensus information overall had a positive effect on perceived consensus among U.S. participants, there was a reduction in perceived consensus and acceptance of human-caused global warming for strong supporters of unregulated free markets. Fitting a Bayes net model to the data indicated that under a Bayesian framework, free-market support is a significant driver of beliefs about climate change and trust in climate scientists. Further, active distrust of climate scientists among a small number of U.S. conservatives drives contrary updating in response to consensus information among this particular group. (shrink)

Over the course of the past several decades, Kant scholars have made significant headway in showing that emotions play a more significant role in Kant's ethics than has traditionally been assumed. Closer attention has been paid to the Metaphysics of Morals (MS) where Kant provides important insights about the value of moral sentiments and the role they should play in our lives. One particularly important discussion occurs in sections 34 and 35 of the Doctrine of Virtue where Kant claims we (...) have a duty to use sympathetic feelings "as a means of promoting active and rational benevolence" (MS 6:457). Kant labels this the "duty of humanity," and he suggests that nature has implanted sympathetic feelings in us "to do what the representation of duty alone might not accomplish" (ibid.). Commentators have rightly highlighted these remarks as prime evidence that feelings do play a positive role in Kant's ethics after all. (shrink)

To understand something involves some sort of commitment to a set of propositions comprising an account of the understood phenomenon. Some take this commitment to be a species of belief; others, such as Elgin and I, take it to be a kind of cognitive policy. This paper takes a step back from debates about the nature of understanding and asks when this commitment involved in understanding is epistemically appropriate, or ‘acceptable’ in Elgin’s terminology. In particular, appealing to lessons from the (...) lottery and preface paradoxes, it is argued that this type of commitment is sometimes acceptable even when it would be rational to assign arbitrarily low probabilities to the relevant propositions. This strongly suggests that the relevant type of commitment is sometimes acceptable in the absence of epistemic justification for belief, which in turn implies that understanding does not require justification in the traditional sense. The paper goes on to develop a new probabilistic model of acceptability, based on the idea that the maximally informative accounts of the understood phenomenon should be optimally probable. Interestingly, this probabilistic model ends up being similar in important ways to Elgin’s proposal to analyze the acceptability of such commitments in terms of ‘reflective equilibrium’. (shrink)

We ordinarily suppose that there is a difference between having and failing to exercise a rational capacity on the one hand, and lacking a rational capacity altogether on the other. This is crucial for our allocations of responsibility. Someone who has but fails to exercise a capacity is responsible for their failure to exercise their capacity, whereas someone who lacks a capacity altogether is not. However, as Gary Watson pointed out in his seminal essay ’Skepticism about Weakness of (...) Will’, the idea of an unexercised capacity is much more difficult to make sense of than it initially appears. The aim of ’Rational Capacities’ is to provide the needed explication of this idea. (shrink)

The present paper investigates the first step of rational belief acquisition. It, thus, focuses on justificatory relations between perceptual experiences and perceptual beliefs, and between their contents, respectively. In particular, the paper aims at outlining how it is possible to reason from the content of perceptual experiences to the content of perceptual beliefs. The paper thereby approaches this aim by combining a formal epistemology perspective with an eye towards recent advances in philosophy of cognition. Furthermore the paper restricts its (...) focus, it concentrates on the case of color perception and perceptual beliefs about color. (shrink)

The question I consider is this: -/- The Question: Can two people–who are, and realize they are, intellectually virtuous to about the same degree–both be rational in continuing knowingly to disagree after full disclosure (by each to the other of all the relevant evidence they can think of) while at the same time thinking that the other may well be rational too? -/- I distinguish two kinds of rationality–internal and external–and argue in section 1 that, whichever kind we (...) have in mind, the answer to The Question is ‘yes’ (though that positive answer is less wholehearted in the case of external rationality). Then, in section 2, I briefly make some more general remarks about when discovering a disagreement provides a defeater and when it doesn't. In the final section, I consider an important objection to the answer given in section 1 to The Question. (shrink)

I argue that rationally persuading another to do something for their own good is sometimes (objectionably) paternalistic. Rational persuasion may express, and be guided by, the motive of distrust in the other’s capacity to gather or weigh evidence, and may intrude on the other’s deliberative activities in ways that conflict with respecting their agency and autonomy. I also examine factors that make a difference to whether (and when) the provision of reasons is respectful.

According to epistemological disjunctivism (ED), in paradigmatic cases of perceptual knowledge, a subject, S, has perceptual knowledge that p in virtue of being in possession of reasons for her belief that p which are both factive and reflectively accessible to S. It has been argued that ED is better placed than both knowledge internalism and knowledge externalism to undercut underdetermination-based skepticism. I identify several principles that must be true if ED is to be uniquely placed to attain this goal. After (...) that, I use those principles to formulate a diachronic skeptical argument. This argument yields the counterintuitive conclusion that understanding a global skeptical hypothesis is all it takes for a rational subject to lose all her perceptual knowledge of the world. Next, I show that a popular Austinian move must reject one or another of the principles that underlie ED. I close by delineating a novel strategy that can block the diachronic skeptical argument while preserving all the principles. The key idea is that perceptual knowledge is grounded in primitive, perceptual and recognitional abilities. This view sheds new light on some puzzling features of global skepticism that have been noted by Descartes and Hume, among others. (shrink)

J. Howard Sobel has long been recognized as an important figure in philosophical discussions of rational decision. He has done much to help formulate the concept of causal decision theory. In this volume of essays Sobel explores the Bayesian idea that rational actions maximize expected values, where an action's expected value is a weighted average of its agent's values for its possible total outcomes. Newcomb's Problem and The Prisoner's Dilemma are discussed, and Allais-type puzzles are viewed from the (...) perspective of causal world Bayesianism. The author establishes principles for distinguishing options in decision problems, and studies ways in which perfectly rational causal maximizers can be capable of resolute choices. Sobel also views critically Gauthier's revisionist ideas about maximizing rationality. This collection will be a desideratum for anyone working in the field of rational choice theory, whether in philosophy, economics, political science, psychology or statistics. Howard Sobel's work in decision theory is certainly among the most important, interesting and challenging that is being done by philosophers. (shrink)

Real-world agents do not know all consequences of what they know. But we are reluctant to say that a rational agent can fail to know some trivial consequence of what she knows. Since every consequence of what she knows can be reached via chains of trivial cot be dismissed easily, as some have attempted to do. Rather, a solution must give adequate weight to the normative requirements on rational agents’ epistemic states, without treating those agents as mathematically ideal (...) reasoners. I’ll argue that agents can fail to know trivial consequences of what they know, but never determinately. Such cases are epistemic oversights on behalf of the agent in question, and the facts about epistemic oversights are always indeterminate facts. As a result, we are never in a position to assert that such-and-such constitutes an epistemic oversight for agent i (for we may rationally assert only determinate truths). I then develop formal epistemic models according to which epistemic accessibility relations are vague. Given these models, we can show that epistemic oversights always concern indeterminate cases of knowledge. (shrink)