Keynes's A Treatise on Probability (Keynes, 1921) contains some quite unusual concepts, such as non-numerical probabilities and the ‘weights of the arguments’ that support probability judgements. Their controversial interpretation gave rise to a huge literature about ‘what Keynes really did mean’, also because Keynes's later views in macroeconomics ultimately rest on his ideas on uncertainty and expectations formation.

Should social preferences conform to the principles of rationality we normally expect of individuals? Should they, for instance, conform to the consistency axioms of expected utility theory? This article considers one fragment of this question.

Over the last few decades, theoretical discussions about metaphors have appeared with increasing frequency in the literature and, during the last fifteen years or so, such discussions have become more and more common in the methodology of economics. But what exactly is a metaphor? According to a tradition which dates back to Aristotle, a metaphor is the attribution to one object, A, of the name (and indirectly of the qualities) of another object, B, while this name or these qualities do not properly or normally belong to A. Thus, a metaphor is present when a term used to describe (or even to name) A is a term which is already commonly used to name B (quite a different kind of entity). Defined in such a way, one must admit that metaphors are frequently found in economics as well as in other sciences. Let us consider, for example, a term like ‘elasticity’ which is extensively used by economists. According to the ordinary dictionary definition, this word designates a property of bodies by which they recover their initial form after having been submitted to a pressure; in a less technical sense, it refers to the flexibility of some bodies or to their responsiveness to pressures.

List and Pettit have stated an impossibility theorem about the aggregation of individual opinion states. Building on recent work on the lottery paradox, this paper offers a variation on that result. The present result places different constraints on the voting agenda and the domain of profiles, but it covers a larger class of voting rules, which need not satisfy the proposition-wise independence of votes.

Discussions of altruism occur in three importantly different contexts. During the past four decades, evolutionary theory has been concerned with the possibility that forms of behaviour labelled as altruistic could emerge and could be maintained under natural selection. In these discussions, an agent A is said to act altruistically towards a beneficiary B when A's action promotes the expected reproductive success of B at expected reproductive cost to A. This sort of altruism, biological altruism, is quite different from the kind of behaviour important to debates about ethical and social issues. There the focus is on psychological altruism, a notion that is concerned with the intentions of the agent and that need have no connection with the spread of anyone's genes. Psychological altruists are people with other-directed desires, emotions or intentions (this is a rough preliminary characterization, to be refined below). Finally, in certain kinds of social scientific research, the important concept is that of behavioural altruism. From the outside, behavioural altruists look like psychological altruists, although their motives and preferences may be very different.

Radical and liberal theories of egalitarianism are distinguished, in large part, by the differing degrees to which they hold people responsible for their own well-being. The most liberal or individualistic theory calls for equality of opportunity. Once such “starting gate equality,” as Dworkin (1981a) calls it, is guaranteed, then any final outcome is justified, provided certain rules, such as voluntary trading, are observed. At the other pole, the most radical egalitarianism calls for equality of welfare (assuming that interpersonal welfare comparisons can be made, so that such equality makes sense). In between these two extremes are egalitarian proposals that equalize more than conventional opportunities, yet less than full welfare. Sen (1980) speaks of equality of basic capabilities as a goal; implementing that requires more than starting gate equality, because some will require more resources than others to attain the same capabilities. Meeting basic needs is another objective. Equality of needs fulfillment is perhaps less radical than equality of basic capabilities and more radical than equality of opportunity. Rawls (1971) takes equality of primary goods as a benchmark; he distinguishes primary goods from welfare, but includes among them goods that are more complicated than conventional resources and opportunities, all of which are supposed inputs into any conception of welfare. One could imagine proposing an egalitarianism that equalized some quite measurable outcome across populations, such as infant mortality. That would be an outcome-equalizing theory where the rate of infant mortality is a proxy, presumably, for some more complicated maximand, such as the degree of wellbeing of a population.

Over the last 40 years or so, economics has become a modelling science: a science in which models have become one of the main epistemological tools both for theoretical and applied work. But providing an account of how models work and what they do for the economist is not easy. For the philosopher of economics like me, struggling with this question, John Sutton's views on the nature and design of economic models and how they work is indeed thought provoking. Because of my own interests, my review of Sutton's book: Marshall's Tendencies: What Can Economists Know? will focus on three related issues that I found especially intriguing in his treatment of the role of models in modern economics. The first is the way that Sutton's account fits with my own reading of the history of twentieth-century economics, namely that the focus of economic explanation has moved during the last century from ‘theories’ and ‘laws’ to ‘models’ and ‘mechanisms’. The second is to understand the epistemological connotations of Sutton's ‘class of models’ view. The third is to explore what Sutton means when he says a model ‘works’. These three questions roughly coincide with the material presented in Chapters 1, 3 and 2 respectively of the book. As we shall see, Sutton gives us a practitioner account of applied economics which can fit within the standard terms used by philosophers of economics on theory-testing, but which reveals a number of novel elements for philosophical analysis.

James Griffin (1986, 1997, 2000) and Ruth Chang (1997) have argued that alternatives (and values) can be comparable when it is neither true that one is better than the other, nor true that they are exactly equal in value. The relation which holds between them has gone under various names: the alternatives are ‘roughly equal in value’ (Griffin) or ‘on a par’ (Chang). In this paper, I give a formal analysis of this relation. This analysis allows us to distinguish between two slightly different notions of ‘at least as good as’. It is argued that the distinction between these notions is important for discussions of rationality, as is the distinction between ‘rough equality’ or ‘parity’ and incomparability.

The standard, Bayesian account of rational belief and decision is often argued to be unable to cope properly with severe uncertainty, of the sort ubiquitous in some areas of policy making. This paper tackles the question of what should replace it as a guide for rational decision making. It defends a recent proposal, which reserves a role for the decision maker’s confidence in beliefs. Beyond being able to cope with severe uncertainty, the account has strong normative credentials on the main fronts typically evoked as relevant for rational belief and decision. It fares particularly well, we argue, in comparison to other prominent non-Bayesian models in the literature.

If group members aim to fulfil a collective obligation, they must act in such a way that the composition of their individual actions amounts to a group action that fulfils the collective obligation. We study a strong sense of joint action in which the members of a group design and then publicly adopt a group plan that coordinates the individual actions of the group members. We characterize the conditions under which a group plan successfully coordinates the group members’ individual actions, and study how the public adoption of a plan changes the context in which individual agents make a decision about what to do.

F. A. Hayek is uniquely responsible for his fellow economists grasping the importance of the decentralization of knowledge: as Hayek shows in his pathbreaking “The Use of Knowledge in Society,” knowledge nowhere exists as a coherent whole and to pretend otherwise is a most serious error. Hayek also shares responsibility for the popularity of a strong form of the methodological individualist research program which asserts that since collectives as such have no impact on the choices of individuals, investigators ought to purge any reliance on collectives from our analysis.

A claim that certain purely private matters should be beyond the reach of society's laws, moral rules, and other customs is central to the distinctive liberalism of John Stuart Mill. On Liberty, perhaps the most eloquent defense of individual liberty ever written, laments the hostility allegedly displayed in modern mass societies toward “the right of each individual to act [in private matters] as seems good to his judgement and inclinations” (1859, p. 271n.). In Mill's view, a free society must design its institutions with due regard for what he terms “individuality.” That is, public authority, whether in the form of law, customary opinion, or economic power, must be self-limiting so that it does not interfere with the rights of individuals to choose as they like with respect to such private concerns as religious faith, reading materials, living companions, and consumption of drugs and alcohol. Individuals and voluntary groups should be permitted to do whatever they prefer within their private spheres even if everyone else in society dislikes what they do, is annoyed by them, and actually chooses not to be around them or to befriend them (1859, pp. 276–91).

One feature of socialism that has been little discussed in the recent revival of interest in Marx is the basic form of economic organization that will characterize such a society. Marx's view, to be documented in what follows, is that socialism would not have a market economy. This prediction should be a matter of some embarrassment or consternation to twentieth-century socialists outside of the Soviet bloc who claim a Marxist heritage. Despite the fact (or perhaps because of the fact) that some socialist regimes in the first half of this century did carry out a program of (largely) abolishing the market, the abolition of markets is no longer on the agenda for developed and developing countries. On the Left, anyway, some form of market socialism seems to be the preferred alternative; Yugoslavia is often pointed to as an imperfect real world exemplar of what market socialism might be like.

G. A. Cohen proposes to eradicate inequality without loss of efficiency or freedom by relying on an egalitarian ethos requiring us to undertake socially useful occupations we would rather not take, and work hard at them, without requesting differential incentive payments. Since the ethos is not legally enforced, Cohen denies it threatens our occupational freedom. Drawing on the work of Joseph Raz, the paper argues that Cohen's proposal threatens our occupational autonomy even if it leaves our legal freedom intact. It also proposes a revised ethos which respects occupational autonomy.

Human behaviour, like everything else, has causes. Most of the time, those causes can be described as reasons. Human beings perform actions because they have reasons for performing them. They are capable of surveying the options available and then selecting one based upon those reasons. But invariably occasions arise in which the reasons known to the agent fail to single out a determinate option. When reasons cannot determine the option to select on their own, the agent must resort to some form of non-reasoned decision-making (NRDM). This paper distinguishes four different forms of NRDM – picking, randomizing, deferring and judging. Each form may be appropriate under different circumstances. The paper concludes by laying out the theoretical assumptions upon which this account of NRDM rests.

We present a new class of models of players’ reasoning in non-cooperative games, inspired by David Lewis's account of common knowledge. We argue that the models in this class formalize common knowledge of rationality in a way that is distinctive, in virtue of modelling steps of reasoning; and attractive, in virtue of being able to represent coherently common knowledge of any consistent standard of individual decision-theoretic rationality. We contrast our approach with that of Robert Aumann (1987), arguing that the former avoids and diagnoses certain paradoxes to which the latter may give rise when extended in particular ways.

In the Common Mind, Pettit argues that rational choice theory cannot provide genuine causal accounts of action. A genuine causal explanation of intentional action must track how people actually deliberate to arrive at action. And, deliberation is necessarily enculturated or situated “. . . we take human agents to reason their way to action, using the concepts that are available to them in the currency of their culture” (p. 220). When deciding how to act, “. . . people find their way to action in response to properties that they register in the options before them, properties that are valued in common with others and that can be invoked to provide at least some justification of their choices” (p. 272). That people seek to make justified decisions implies that, at times, their own goals or objectives will be modified in deliberation. Something that rational choice theory cannot allow.