How should one react when one has a belief, but knows that other people—who have roughly the same evidence as one has, and seem roughly as likely to react to it correctly—disagree? This paper argues that the disagreement of other competent inquirers often requires one to be much less confident in one’s opinions than one would otherwise be.

Richard Jeffrey regarded the version of Bayesian decision theory he floated in ‘The Logic of Decision’ and the idea of a probability kinematics—a generalisation of Bayesian conditioning to contexts in which the evidence is ‘uncertain’—as his two most important contributions to philosophy. This paper aims to connect them by developing kinematical models for the study of preference change and practical deliberation. Preference change is treated in a manner analogous to Jeffrey’s handling of belief change: not as mechanical outputs of combinations (...) of intrinsic desires plus information, but as a matter of judgement and of making up one’s mind. In the first section Jeffrey’s probability kinematics is motivated and extended to the treatment of changes in conditional belief. In the second, analogous kinematical models are developed for preference change and in particular belief-induced change that depends on an invariance condition for conditional preference. The two are the brought together in the last section in a tentative model of pratical deliberation. (shrink)

Diversity of opinion both presents problems and aff ords opportunities. Diff erences of opinion can stand in the way of reaching an agreement within a group on what decisions to take. But at the same time, the fact that the differences in question could derive from access to different information or from the exercise of diff erent judgemental skills means that they present individuals with the opportunity to improve their own opinions. This paper explores the implications for solutions to the (...) former (aggregation) problem of supposing that individuals exploit these opportunities. In particular, it argues that rational individual revision of opinion implies that aggregation problems are unstable in a certain sense and that solving them by exploiting the information embedded in individual opinion has profound implications for the conditions that we should impose on aggregation procedures. (shrink)

This article examines Becker's thesis that the hypothesis that choices maximize expected utility relative to fixed and universal tastes provides a general framework for the explanation of behaviour. Three different models of preference revision are presented and their scope evaluated. The first, the classical conditioning model, explains all changes in preferences in terms of changes in the information held by the agent, holding fundamental beliefs and desires fixed. The second, the Jeffrey conditioning model, explains them in terms of changes in (...) both the information held by the agent and changes in her prior beliefs, holding her fundamental desires fixed. The final model, that of generalized conditioning, allows for explanations in terms of changes in the values of all three variables. Key Words: preference change • decision theory • probability • desirability • attitude change. (shrink)

My aim in this paper is to develop and defend a novel answer to a question that has recently generated a considerable amount of controversy. The question concerns the normative significance of peer disagreement. Suppose that you and I have been exposed to the same evidence and arguments that bear on some proposition: there is no relevant consideration which is available to you but not to me, or vice versa. For the sake of concreteness, we might picture.

Group decisions raise a number of substantial philosophical and methodological issues. We focus on the goal of the group decision exercise itself. We ask: What should be counted as a good group decision-making result? The right decision might not be accessible to, or please, any of the group members. Conversely, a popular decision can fail to be the correct decision. In this paper we discuss what it means for a decision to be "right" and what components are required in a (...) decision process to produce happy decision-makers. Importantly, we discuss how "right" decisions can produce happy decision-makers, or rather, the conditions under which happy decision-makers and right decisions coincide. In a large range of contexts, we argue for the adoption of formal consensus models to assist in the group decision-making process. In particular, we advocate the formal consensus convergence model of Lehrer and Wagner (1981), because a strong case can be made as to why the underlying algorithm produces a result that should make each of the experts in a group happy. Arguably, this model facilitates true consensus, where the group choice is effectively each person's individual choice. We analyse Lehrer and Wagner's algorithm for reaching consensus on group probabilities/utilities in the context of complex decision-making for conservation biology. While many conservation decisions are driven by a search for objective utility/probability distributions (regarding extinction risks of species and the like), other components of conservation management primarily concern the interests of stakeholders. We conclude with cautionary notes on mandating consensus in decision scenarios for which no fact of the matter exists. For such decision settings alternative types of social choice methods are more appropriate. (shrink)

Most moral philosophers who have recently expressed sympathy with feminist or ‘care-based’ perspectives on ethical theory have thought that such perspectives can make valuable contributions to more comprehensive ethical theories. Few have thought that an ethics of care can offer a complete normative theory. However, Michael Slote is one of the ambitious few. In his recent book, The Ethics of Care and Empathy, he seeks to show that a care-based perspective can do a lot of service in first-order moral and (...) political theory as well as in metaethics. Here is a quick overview of the book's content: In Chapter 1, Slote explicates the notion of empathy that is central in his ethics of care, which he locates within the sentimentalist paradigm, stemming from philosophers such as Hume and Hutcheson. Slote's account of empathy and moral development draws substantially on work by the psychologist Martin Hoffman. Chapter 2 discusses care ethics and our obligation to help others, including both the near and the distant needy. Chapter 3 aims to show how the notion of empathy can further the case for deontology in ethics. Chapters 4 through 6 discuss the relation of care ethics to pivotal issues in political philosophy, such as autonomy, liberalism, social justice and rights. Slote maintains that autonomy …. (shrink)

Weighted averaging is a method for aggregating the totality of information, both regimented and unregimented, possessed by an individual or group of individuals. The application of such a method may be warranted by a theorem of the calculus of probability, simple conditionalization, or Jeffrey's formula for probability kinematics, all of which average in terms of the prior probability of evidence statements. Weighted averaging may, however, be applied as a method of rational aggregation of the probabilities of diverse perspectives or persons (...) in cases in which the weights cannot be articulated as the prior probabilities of statements of evidence. The method is justified by Wagner's Theorem exhibiting that any method satisfying the conditions of the Irrelevance of Alternatives and Zero Unanimity must, when applied to three or more alternatives, be weighted averaging. (shrink)

Virginia Held assesses the ethics of care as a promising alternative to the familiar moral theories that serve so inadequately to guide our lives. The ethics of care is only a few decades old, yet it is by now a distinct moral theory or normative approach to the problems we face. It is relevant to global and political matters as well as to the personal relations that can most clearly exemplify care. This book clarifies just what the ethics of care (...) is: what its characteristics are, what it holds, and what it enables us to do. It discusses the feminist roots of this moral approach and why the ethics of care can be a morality with universal appeal. Held examines what we mean by "care," and what a caring person is like. Where other moral theories demand impartiality above all, the ethics of care understands the moral import of our ties to our families and groups. It evaluates such ties, focusing on caring relations rather than simply on the virtues of individuals. The book proposes how such values as justice, equality, and individual rights can "fit together" with such values as care, trust, mutual consideration, and solidarity. In the second part of the book, Held examines the potential of the ethics of care for dealing with social issues. She shows how the ethics of care is more promising than Kantian moral theory and utilitarianism for advice on how expansive, or not, markets should be, and on when other values than market ones should prevail. She connects the ethics of care with the rising interest in civil society, and considers the limits appropriate for the language of rights. Finally, she shows the promise of the ethics of care for dealing with global problems and seeing anew the outlines of international civility. (shrink)

In many scientific, economic and policy-related problems, pieces of information from different sources have to be aggregated. Typically, the sources are not equally competent. This raises the question of how the relative weights and competences should be related to arrive at an optimal final verdict. Our paper addresses this question under a more realistic perspective of measuring the practical loss implied by an inaccurate verdict.

How should you take into account the opinions of an advisor? When you completely defer to the advisor's judgment, then you should treat the advisor as a guru. Roughly, that means you should believe what you expect she would believe, if supplied with your extra evidence. When the advisor is your own future self, the resulting principle amounts to a version of the Reflection Principle---a version amended to handle cases of information loss. When you count an advisor as an epistemic (...) peer, you should give her conclusions the same weight as your own. Denying that view---call it the ``equal weight view''---leads to absurdity: the absurdity that you could reasonably come to believe yourself to be an epistemic superior to an advisor simply by noting cases of disagreement with her, and taking it that she made most of the mistakes. Accepting the view seems to lead to another absurdity: that one should suspend judgment about everything that one's smart and well-informed friends disagree on, which means suspending judgment about almost everything interesting. But despite appearances, the equal weight view does not have this absurd consequence. Furthermore, the view can be generalized to handle cases involving not just epistemic peers, but also epistemic superiors and inferiors. (shrink)

CONSENSUS AND PHILOSOPHICAL ISSUES Various atomistic and individualistic theories of knowledge, language, ethics and politics have dominated philosophical ...

Eminent moral philosopher Michael Slote argues that care ethics presents an important challenge to other ethical traditions and that a philosophically developed care ethics should, and can, offer its own comprehensive view of the whole of morality. Taking inspiration from British moral sentimentalism and drawing on recent psychological literature on empathy, he shows that the use of that notion allows care ethics to develop its own sentimentalist account of respect, autonomy, social justice, and deontology. Furthermore, he argues that care ethics (...) gives a more persuasive account of these topics than theories offered by contemporary Kantian liberalism. The most philosophically rich and challenging exploration of the theory and practice of care to date, _The Ethics of Care and Empathy_ also shows the manifold connections that can be drawn between philosophical issues and leading ideas in the fields of psychology, education, and women's studies. (shrink)

This paper applies the theory of networks to the problem of how agents should assign weights to other agents in the Lehrer-Wagner model for consensus formation. The Lehrer- Wagner theory of consensus is introduced, and the problem of weight assignment is highlighted as one of the open prob- lems for the theory. The paper argues that the application of the theory of networks to the Lehrer-Wagner model con- stitutes an interesting and fruitful option, among others, for the problem of weight (...) assignment. (shrink)

This paper applies the theory of networks to the problem of how agents should assign weights to other agents in the Lehrer-Wagner model for consensus formation. The Lehrer- Wagner theory of consensus is introduced, and the problem of weight assignment is highlighted as one of the open prob- lems for the theory. The paper argues that the application of the theory of networks to the Lehrer-Wagner model con- stitutes an interesting and fruitful option, among others, for the problem of weight (...) assignment. (shrink)

How can the propositional attitudes of several individuals be aggregated into overall collective propositional attitudes? Although there are large bodies of work on the aggregation of various special kinds of propositional attitudes, such as preferences, judgments, probabilities and utilities, the aggregation of propositional attitudes is seldom studied in full generality. In this paper, we seek to contribute to filling this gap in the literature. We sketch the ingredients of a general theory of propositional attitude aggregation and prove two new theorems. (...) Our first theorem simultaneously characterizes some prominent aggregation rules in the cases of probability, judgment and preference aggregation, including linear opinion pooling and Arrovian dictatorships. Our second theorem abstracts even further from the specific kinds of attitudes in question and describes the properties of a large class of aggregation rules applicable to a variety of belief-like attitudes. Our approach integrates some previously disconnected areas of investigation. (shrink)