Economists often argue that we must discount future costs and benefits because if we did not, this would have the absurd implication that we should invest nearly all our resource to benefit vast numbers of future people. Moreover, not discounting would supposedly result in what Tjalling Koopmans called the ‘paradox of the indefinitely postponed splurge’: we could never use the resources because we could always do more good by reinvesting them. This paper will attack these claims on three fronts.
First, it will question whether it is empirically true that resources invested now could benefit people for many centuries or millennia in the future. Would we be significantly better off if the ancient Greeks or Romans had had a higher investment rate? While we can benefit the distant future both through cultural legacies and by leaving an unspoiled planet, it seems doubtful that material investment has high long term payoffs.
Second, it will argue that Koopman’s paradox solves itself. Moral prescriptions must be universalisable; if it would be right for us to invest nearly all our income, it would be right for every succeeding generation in a relevantly similar position. Precisely because this would lead to perpetual impoverishment, no plausible theory could reasonably require it.
Finally, at the level of axiology—what R. M. Hare called the critical level—we should accept ‘chocolates for the well off’: that *theoretically* it could be best to impoverish ourselves for the sake of small benefits to future rich people. But since any theory that required this would have abominable results, in practice no reasonable version of consequentialism will ever tell us to do so. Instead, we will maximize long-term value by ensuring that each generation has a decent living standard, with the sufficiency view serving as our Harean prima facie principle.
