Deliberation about what to do in any context requires reasoning about what will or would happen in various alternative situations, including situations that the agent knows will never in fact be realized. In contexts that involve two or more agents who have to take account of each others' deliberation, the counterfactual reasoning may become quite complex. When I deliberate, I have to consider not only what the causal effects would be of alternative choices that I might make, but also what other agents might believe about the potential effects of my choices, and how their alternative possible actions might affect my beliefs. Counterfactual possibilities are implicit in the models that game theorists and decision theorists have developed – in the alternative branches in the trees that model extensive form games and the different cells of the matrices of strategic form representations – but much of the reasoning about those possibilities remains in the informal commentary on and motivation for the models developed. Puzzlement is sometimes expressed by game theorists about the relevance of what happens in a game ‘off the equilibrium path’: of what would happen if what is (according to the theory) both true and known by the players to be true were instead false.

In this article, I shall suggest an approach to the justification of normative moral principles which leads, I think, to utilitarianism. The approach is based on asking what moral norms we would each endorse if we had no prior moral commitments. I argue that we would endorse norms that lead to the satisfaction of all our nonmoral values or goals. The same approach leads to a view of utility as consisting of those goals that we would want satisfied. In the second half of the article, I examine the implication of this view for several issues about the nature of utility, such as the use of past and future goals. The argument for utilitarianism is not completed here. The rest of it requires a defense of expected-utility theory, of interpersonal comparison, and of equal consideration (see Baron, 1993; Broome, 1991).

Professor Hausman has written an interesting and instructive book. Though I am by no means favourably disposed to methodology for economists, (its results seem to have been pretty disastrous), I found reading Hausman enjoyable and I came away having learned things worth learning. But not all is well, largely because Hausman is a philosopher first and an economist a poor second. There are also important questions where one would have expected philosophic help which are not asked at all.

1. Despite the plain fact that there is nothing in this world that can be proved without reliance on some assumption or another (perhaps only the assumption that the laws of logic are correct), there is an inalienable difference between an argument that begins by assuming what it is designed to establish and one that begins by assuming the contradictory of what it is designed to establish. Arguments of the first kind are uncontroversially acknowledged to be circular, or question-begging; though valid they achieve nothing. Those of the second kind conform to the classical pattern of reductio ad absurdum or indirect proof. A typical example is the proof of the irrationality of √2, which begins by assuming that for some integral m, n the identity m2/n2 = 2, and (using some trite principles of number theory) arrives at a contradiction. Nothing whatever is established or justified by arguments of the first kind, even granted the truth of all the other assumptions (if any), and the validity of the rules of inference; while the second may establish that, if those assumptions are true (and the rules of inference employed valid), then the additional assumption (that √2 is rational) is false.

The Inexact and Separate Science of Economics (ISSE) offers an overview of standard microeconomics and general equilibrium theory. These are not the whole of orthodox economics, and orthodox economics is not the whole of economics. But orthodox economics dominates the profession, and the theoretical core of microeconomics and general equilibrium theory – what I called ‘equilibrium theory’ – is central to most orthodox economics. Unlike many methodological works, which focus almost exclusively on the empirical problems of equilibrium theory and its applications, ISSE is also concerned with the structure, strategy and heuristics of equilibrium theorizing, and it attempts to link questions about theory appraisal to questions about structure and strategy. It is addressed both to philosophers interested in epistemological questions posed by the social sciences and to economists interested in reflecting on and improving their discipline. Its inspiration lies in the work of John Stuart Mill.