Intertemporal Impartial Welfare Maximization: Replacing Discounting by Probability Weighting

Impartiality requires putting the welfare of future generations at par with that of our own. However, rational choice requires weighting all welfare values by the respective probabilities of realization. As the risk of non-survival of mankind is strictly positive for all time periods and as the probability of non-survival is cumulative, the probability weights operate like discount factors, though justified on a morally justifiable and completely different ground. Impartial intertemporal welfare maxirnization is acceptable though the welfare of people in the very far future has no significant effect. As the probability of people existing a trillion to the power of a trillion centuries from now is close to zero, the fact that their voice now is also close to zero should not be regarded as the dictatorship of the present, properly interpreted.