Several philosophers have argued that interpersonal comparisons of utility are problematic or even impossible, and that this poses a problem for the thesis that pleasure is a legitimate, measurable quantity. This, in turn, is thought to pose a problem of some kind for a variety of normative ethical and axiological theories. Perhaps it is supposed to show that utilitarianism or hedonism is false, or is supposed to show that there is no genuine hedonic calculus, or that any view that presupposes (...) that pleasure and pain are morally relevant is false or untenable. Its proponents begin by noticing that interpersonal comparisons of pleasure and pain are impossible in some relevant sense. This impossibility has been exploited by different philosophers for different purposes. It is clear, however, that a great many ethical theories rely in some way on the thesis that pleasure is measurable, and that its incoherence therefore threatens a great many theories in ethics. The purpose of this paper is to survey several of the most interesting versions of this argument; then to explain several attempts to respond to the problem, and to explain why each attempt fails; then to present, explain, and defend the correct solution to the problem. (shrink)

According to several prominent philosophers, pleasure and pain come in measurable quantities. This thesis is controversial, however, and many philosophers have presented or felt compelled to respond to arguments for the conclusion that it is false. One important class of these arguments concerns the problem of aggregation, which says that if pleasure and pain were measurable quantities, then, by definition, it would be possible to perform various mathematical and statistical operations on numbers representing amounts of them. It is sometimes argued (...) that such operations cannot be sensibly applied to pleasure and pain, and that sentences expressing such operations must be false or meaningless. The purpose of this paper is to present, explain, and rebut several versions of this argument. In the first section, I present a generic version of the argument. In the second section, I present a defense of its key premise based on a case involving comparisons of relief from pain, and explain why I think it fails. In the third section, I present and rebut another defense, based on a pair of analogies with temperature. In the final section, I present a third defense, based on an analogy with spatial distances. I then present my reasons for rejecting it. Along the way, I explain my reasons for thinking that pleasure and pain are amenable to interval measurement. (shrink)