Recent debates over climate change policy have made it clear that the choice of a social discount rate has enormous consequences for the amount of mitigation that will be recommended. The social discount rate determines how future costs are to be compared to present costs. Philosophers, however, have been almost unanimous in endorsing the view that the only acceptable social rate of time preference is zero, a view that, taken literally, has either absurd or extremely radical implications. The first goal (...) of this paper is to show that the standard arguments against temporal preference are much less persuasive than they are usually taken to be. The second goal is to explore two different avenues of argument that could be adopted, in order to show that temporal discounting of welfare may be permissible. The first involves simply an application of the method of reflective equilibrium, while the second involves consideration of the way that our abstract moral commitments are institutionalized. (shrink)

Many people believe that we have responsibility towards the distant future, but exactly how far this responsibility reaches and how we can find a reasonable ethical foundation for it has not been answered in any definitive manner. Future people have no power over us, they form no part of our moral community and it is unclear how we can represent them in a possible original position. All these problems can be circumvented when you take an impersonal decision criterion like maximizing (...) total or average utility. Such a sum-ranking criterion is neutral with respect to distance in time or space: my utility, my neighbour's and that of our descendants all carry the same weight. This makes future people an integral part of present decisions. Time-neutrality was defended by, among others, Sidgwick, Pigou and Ramsey. (shrink)