  There is a more general point here, which was explored by Koopmans (1960, 1965, 1967, 1972) in a remarkable set of publications on the idea of economic development. In such complex exercises as those involving consumption and investment over a long time horizon, it is foolish to regard any ethical principle (e.g., Classical Utilitarianism) as sacrosanct. One can never know in advance what it may run up against. A more judicious tactic than Ramsey’s would be to to play off one set of ethical assumptions against another in not-implausible worlds, see what their implications are for the distribution of well-being across generations, and then appeal to our intuitive senses before arguing over policy. Settling ex ante whether to use a positive rate to discount future well-beings could be a self-defeating  move.[1]