Judgment-aggregation theory has always focused on the attainment of rational collective judgments. But so far, rationality has been understood in static terms: as coherence of judgments at a given time, defined as consistency, completeness, and/or deductive closure. This paper asks whether collective judgments can be dynamically rational, so that they change rationally in response to new information. Formally, a judgment aggregation rule is dynamically rational with respect to a given revision operator if, whenever all individuals revise their judgments in (...) light of some information (a learnt proposition), then the new aggregate judgments are the old ones revised in light of this information, i.e., aggregation and revision commute. We prove an impossibility theorem: if the propositions on the agenda are non-trivially connected, no judgment aggregation rule with standard properties is dynamically rational with respect to any revision operator satisfying some basic conditions on revision. Our theorem is the dynamic-rationality counterpart of some well-known impossibility theorems for static rationality. We also explore how dynamic rationality might be achieved by relaxing some of the conditions on the aggregation rule and/or the revision operator. Notably, premise-based aggregation rules are dynamically rational with respect to so-called premise-based revision operators. (shrink)

This is a major contribution to the theory of rational choice which will be of particular interest to philosophers and economists. The author sets out the foundations of rational choice, and then sketches a dynamic choice framework in which principles of ordering and independence follow from a number of apparently plausible conditions. However, there is potential conflict among these conditions, and when they are weakened to avoid it the usual foundations of rational choice no longer prevail. The thrust of (...) the argument is to suggest that the theory of rational choice is less deterministic than many suppose. (shrink)

Brian Skyrms constructs a theory of "dynamic deliberation" and uses it to investigate rational decision-making in cases of strategic interaction. This illuminating book will be of great interest to all those in many disciplines who use decision theory and game theory to study human behavior and thought. Skyrms begins by discussing the Bayesian theory of individual rational decision and the classical theory of games, which at first glance seem antithetical in the criteria used for determining action. In his effort (...) to show how methods for dealing with information feedback can be productively combined, the author skillfully leads us through the mazes of equilibrium selection, the Nash equilibria for normal and extensive forms, structural stability, causal decision theory, dynamic probability, the revision of beliefs, and, finally, good habits for decision. The author provides many clarifying illustrations and a handy appendix called "Deliberational Dynamics on Your Personal Computer." His powerful model has important implications for understanding the rational origins of convention and the social contract, the logic of nuclear deterrence, the theory of good habits, and the varied strategies of political and economic behavior. (shrink)

Game-theoretic solution concepts describe sets of strategy profiles that are optimal for all players in some plausible sense. Such sets are often found by recursive algorithms like iterated removal of strictly dominated strategies in strategic games, or backward induction in extensive games. Standard logical analyses of solution sets use assumptions about players in fixed epistemic models for a given game, such as mutual knowledge of rationality. In this paper, we propose a different perspective, analyzing solution algorithms as processes of (...) learning which change game models. Thus, strategic equilibrium gets linked to fixed-points of operations of repeated announcement of suitable epistemic statements. This dynamic stance provides a new look at the current interface of games, logic, and computation. (shrink)

Classical theories of epistemic rationality take an agent\\textquoteright{}s individual beliefs to be the only things that are rational or irrational. For them, rationality is wholly static. Recent work in epistemology take sets of individual beliefs and also changes of belief over time to be rational or irrational. For these theories, rationality is both static and dynamic. However, for both groups, static rationality is fundamental. In my dissertation, I argue to the contrary that, in fact, all (...) rationality is dynamic rationality. Epistemic reasons, rationality, and justi{}cation as applying only to changes of belief. This wholly dynamic view of rationality, which I call \\textquotedblleft{}Dynamicism\\textquotedblright has wide-ranging epistemological consequences. A small set of simple, elegant, and independently motivated principles of dynamic rationality can illuminate and solve otherwise interminable epistemological disputes. (shrink)

Implicit attitudes are mental states posited by psychologists to explain behaviors including implicit racial and gender bias. In this paper I investigate the belief view of the implicit attitudes, on which implicit attitudes are a kind of implicit belief. In particular, I focus on why implicit attitudes, if they are beliefs, are often resistant to updating in light of new evidence. I argue that extant versions of the belief view do not give a satisfactory account of this phenomenon. This is (...) because proponents of the belief view have focused on overly narrow explanations of recalcitrance in terms of belief storage. Expanding the focus of the belief view to the kinds of irrational and arational transitions between beliefs and other mental states provides compelling (if preliminary) explanations of recalcitrance. (shrink)

Oaksford & Chater (O&C) focus on patterns of typical adult reasoning from a probabilistic perspective. We discuss implications of extending the probabilistic approach to lifespan development, considering the role of working memory, strategy use, and expertise. Explaining variations in human reasoning poses a challenge to Bayesian rational analysis, as it requires integrating knowledge about cognitive processes.

This paper contrasts a picoeconomic approach to theexplanation of akrasia with Davidson's divided-mind approach and defends theformer in a wider context. The distinctive merits of a picoeconomic model of mindlie in the following aspects: First, it relies on a scientifically well-groundeddiscovery about motivational dynamics of animals for its explanation of preference change,which elucidates or materializes some philosophers' speculations both about thepossible mismatch between valuation and motivation and about the relevance of temporalfactors to akrasia. Second, it grounds the necessity of endogenous (...) higher-order constraints,expressible in forms of judgment, in an intrapersonal dynamic process of interactivefirst-order temporary preferences. Thus the motivational basis for the normativeconstruction of the rationality of `best judgment' can also be illuminated with this model. (shrink)

We provide a brief introduction to this special issue on social dynamics and collective rationality, and summarize the gist of the papers collected therein.

Whereas The Stag Hunt and the Evolution of Social Structure supplements Evolution of the Social Contract by examining some of the earlier work’s strategic problems in a local interaction setting, no equivalent supplement exists for The Dynamics of Rational Deliberation . In this article, I develop a general framework for modeling the dynamics of rational deliberation in a local interaction setting. In doing so, I show that when local interactions are permitted, three interesting phenomena occur: (a) the attracting deliberative equilibria (...) may fail to agree with any of the Nash equilibria of the underlying game, (b) deliberative dynamics which converged to the same deliberative outcome in The Dynamics of Rational Deliberation may lead to different deliberative outcomes here, and (c) Bayesian deliberation seems to be more likely to avoid nonstandard deliberative outcomes, contrary to the result reported in The Dynamics of Rational Deliberation , which argued in favour of the Brown–von Neumann–Nash dynamics. (shrink)

How can one knowingly choose against one's best judgment? This is both a traditional philosophical puzzle and a realistic problem in our everyday life. This dissertation is an exposition and examination of a recent work, by George Ainslie, with regard to its innovative explanation as well as rational solution of such a problem. With the help of the new Ainsliean model, I have also sought to offer some analysis of a number of issues that I believe are important to the (...) understanding of the nature of practical rationality. ;The central question for Ainslie's approach to the dynamic problem of preference change is how to justify the "bundling" idea underlying his solution of the problem by adopting a "personal rule." The bundling idea is a belief in the relation between a series of similar choices as each predicting the direction of all the later choices. Being able to think in terms of this bundling idea is a powerful means of abstaining from defection, though it requires considerable cognitive effort. I try to defend the plausibility of such a personal-rule approach. But Ainslie's own account falls short of showing the ultimate necessity of the bundling idea, viz., why the collapse of the whole sequence of choices would necessarily follow from one defection. My argument hinges on demonstrating that neither a causal consideration about the links between similar choices, nor a prudential consideration about the possible risk involved in certain actions is sufficient for understanding the necessity: we need a normative perspective instead. ;This leads to my analysis of the conditions under which a normative solution can be justified. The analysis also delineates the type of dynamic choice situations Ainslie's approach may adequately fit, or have the greatest advantage. Some underlying hypothesis about the status and role of cognition in desire and higher-level motivation is carefully discussed; and the cognitive, deliberative, and affective aspects of the adoption of a rule is explored. During my discussions, I also compare Ainslie's approach with other theories in the domain of practical reasoning, such as that of Donald Davidson's, Jon Elster's, Michael Bratman's, Edward McClennen's, and David Gauthier's, in terms of their explanatory power, or their scope of application, limits, and complementarity. ;Ainslie's motivational model of mind has apparent as well as potential implications for a group of interesting philosophical issues. They include the nature of willpower, the nature of practical rationality as well as moral rules, personal identity, autonomy, and the existentialist theme on self-creation. My conclusion is that the clarification of the metaphysical underpinnings of the Ainsliean model can help to shed some light on these issues. (shrink)

Putnam’s internal realism implies a form of conceptual relativity with respect to ontology. There can be different descriptions of the world which are based on distinct ontologies. It has been argued that this relativity forecloses any possibility of unifying our knowledge and can even lead to inconsistency. If this is true, internal realism should be abandoned because it is compatible with non-rational positions. We will argue that these objections can be dismissed if truth as idealized warranted assertibility is understood as (...) stability of a belief state under new evidence. This view of truth is still compatible with the existence of distinct belief states expressing different views on the world. This understanding of the notion of truth is a consequence of interpreting both our cognitive activities and the notion of meaning dynamically. The meaning of a sentence is no longer given in terms of (static) truth conditions but as a relation between belief sets, that is, as a kind of information change potential. (shrink)

review of McLennen's *Rationality and Dynamic Choice*. The topic is important and the discussion is powerful. Some connection with modelling and simulation would be valuable.

What I’m calling “Subjective Logic” is a new approach to logic. Fundamentally it is a theory about what sentences mean, i.e. a theory of the proposition, but it includes an account of logical consequence, the propositional connectives, probability, and the nature of truth.

Sometimes a series of choices do not serve one's concerns well even though each choice in the series seems perfectly well suited to serving one's concerns. In such cases, one has a dynamic choice problem. Otherwise put, one has a problem related to the fact that one's choices are spread out over time. This survey reviews some of the challenging choice situations and problematic preference structures that can prompt dynamic choice problems. It also reviews some proposed solutions, and (...) explains how some familiar but potentially puzzling phenomena — including, for example, self-destructive addictive behavior and dangerous environmental destruction — have been illuminated by dynamic choice theory. (shrink)

We formalise a notion of dynamic rationality in terms of a logic of conditional beliefs on (doxastic) plausibility models. Similarly to other epistemic statements (e.g. negations of Moore sentences and of Muddy Children announcements), dynamic rationality changes its meaning after every act of learning, and it may become true after players learn it is false. Applying this to extensive games, we “simulate” the play of a game as a succession of dynamic updates of the original (...) plausibility model: the epistemic situation when a given node is reached can be thought of as the result of a joint act of learning (via public announcements) that the node is reached. We then use the notion of “stable belief”, i.e. belief that is preserved during the play of the game, in order to give an epistemic condition for backward induction: rationality and common knowledge of stable belief in rationality. This condition is weaker than Aumann’s and compatible with the implicit assumptions (the “epistemic openness of the future”) underlying Stalnaker’s criticism of Aumann’s proof. The “dynamic” nature of our concept of rationality explains why our condition avoids the apparent circularity of the “backward induction paradox”: it is consistent to (continue to) believe in a player’s rationality after updating with his irrationality. (shrink)

There has been considerable philosophical debate in recent years over a thesis called epistemic permissivism. According to the permissivist, it is possible for two agents to have the exact same total body of evidence and yet differ in their belief attitudes towards some proposition, without either being irrational. However, I argue, not enough attention has been paid to the distinction between different ways in which permissivism might be true. In this paper, I present a taxonomy of forms of epistemic permissivism (...) framed as the upshot of different ways one might respond to a basic argument against the view from Roger White. I then introduce a new type of permissive view which the contemporary debate has completely ignored and which is made available when we reject a widespread and largely unexamined background commitment to static rational norms connecting beliefs and evidence in favor of dynamic norms governing processes of consideration. I show how the dynamic strategy of rejecting static norms on belief opens the door to a new kind of permissivism which is both independently attractive and especially well-placed to answer worries that have been raised against traditional permissivist views. (shrink)

Epistemic logics based on the possible worlds semantics suffer from the problem of logical omniscience, whereby agents are described as knowing all logical consequences of what they know, including all tautologies. This problem is doubly challenging: on the one hand, agents should be treated as logically non-omniscient, and on the other hand, as moderately logically competent. Many responses to logical omniscience fail to meet this double challenge because the concepts of knowledge and reasoning are not properly separated. In this paper, (...) I present a dynamic logic of knowledge that models an agent’s epistemic state as it evolves over the course of reasoning. I show that the logic does not sacrifice logical competence on the altar of logical non- omniscience. (shrink)

A dynamic epistemic logic is presented in which the single agent can reason about his knowledge stages before and after announcements. The logic is generated by reinterpreting multi agent private announcements in a single agent environment. It is shown that a knowability principle is valid for such logic: any initially true ϕ can be known after a certain number of announcements.

This paper argues that instrumental rationality is more permissive than expected utility theory. The most compelling instrumentalist argument in favour of separability, its core requirement, is that agents with non-separable preferences end up badly off by their own lights in some dynamic choice problems. I argue that once we focus on the question of whether agents’ attitudes to uncertain prospects help define their ends in their own right, or instead only assign instrumental value in virtue of the outcomes (...) they may lead to, we see that the argument must fail. Either attitudes to prospects assign non-instrumental value in their own right, in which case we cannot establish the irrationality of the dynamic choice behaviour of agents with non-separable preferences. Or they don’t, in which case agents with non-separable preferences can avoid the problematic choice behaviour without adopting separable preferences. (shrink)

In the social sciences norms are sometimes taken to play a key explanatory role. Yet norms differ from group to group, from society to society, and from species to species. How are norms formed and how do they change? This 'state-of-the-art' collection of essays presents some of the best contemporary research into the dynamic processes underlying the formation, maintenance, metamorphosis and dissolution of norms. The volume combines formal modelling with more traditional analysis, and considers biological and cultural evolution, individual (...) learning, and rational deliberation. In filling a significant gap in the current literature this volume will be of particular interest to economists, political scientists and sociologists, in addition to philosophers of the social sciences. (shrink)

Man is a rational animal, or so says Aristotle.1 But what is rationality? It is the use of reason to reach a certain level of reasonableness or unreasonableness. To be rational is to be extremely reasonable as to be irrational is to be extremely unreasonable. The varieties of rationality and distinctions about rationality are many. First of all, there is a distinction between practical and theoretical rationality. Secondly, there is a distinction between synchronic or static (...) class='Hi'>rationality and diachronic or dynamic rationality. Thirdly, there is a distinction between personal rationality and interpersonal rationality. Combinations of these kinds of rationality yield eight kinds of rationality. (shrink)

This book introduces a new approach to the issue of radical scientific revolutions, or "paradigm-shifts," given prominence in the work of Thomas Kuhn. The book articulates a dynamical and historicized version of the conception of scientific a priori principles first developed by the philosopher Immanuel Kant. This approach defends the Enlightenment ideal of scientific objectivity and universality while simultaneously doing justice to the revolutionary changes within the sciences that have since undermined Kant's original defense of this ideal. Through a modified (...) Kantian approach to epistemology and philosophy of science, this book opposes both Quinean naturalistic holism and the post-Kuhnian conceptual relativism that has dominated recent literature in science studies. Focussing on the development of "scientific philosophy" from Kant to Rudolf Carnap, along with the parallel developments taking place in the sciences during the same period, the author articulates a new dynamical conception of relativized a priori principles. This idea applied within the physical sciences aims to show that rational intersubjective consensus is intricately preserved across radical scientific revolutions or "paradigm-shifts and how this is achieved. (shrink)

This book introduces a new approach to the issue of radical scientific revolutions, or "paradigm-shifts," given prominence in the work of Thomas Kuhn. The book articulates a dynamical and historicized version of the conception of scientific a priori principles first developed by the philosopher Immanuel Kant. This approach defends the Enlightenment ideal of scientific objectivity and universality while simultaneously doing justice to the revolutionary changes within the sciences that have since undermined Kant's original defense of this ideal. Through a modified (...) Kantian approach to epistemology and philosophy of science, this book opposes both Quinean naturalistic holism and the post-Kuhnian conceptual relativism that has dominated recent literature in science studies. Focussing on the development of "scientific philosophy" from Kant to Rudolf Carnap, along with the parallel developments taking place in the sciences during the same period, the author articulates a new dynamical conception of relativized a priori principles. This idea applied within the physical sciences aims to show that rational intersubjective consensus is intricately preserved across radical scientific revolutions or "paradigm-shifts and how this is achieved. (shrink)