Appropriate discounting of future utilities need not be the dictatorship of the present: A note on Chichilnisky

Positive, but non-excessive discounting of future utilities to take account of possible non-realization/survival is not the dictatorship of the present, contrary to Chichilnisky’s argument which is ingenious but contains a slip due to the improper treatment of infinity. As the probability of people existing a trillion to the power of a trillion years 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. Correspondingly, Chichilnisky’s criterion which gives the welfare of people in year infinity some extra weight over-and-above their due weight in accordance to the realization probability, is not acceptable. In an interesting paper in this journal, Chichilnisky (1996) addresses the important problem of sustainable development and comes out with some very provocative conclusions. The main result of Chichilnisky is rather neat and can be simply explained. Under the axioms that neither the present nor the future should be dictatorial (apparently reasonable, but more below), she argues that the objective function should be a combination of both the discounted sum/integral of utilities/welfares and Soc Choice Welfare (2003) 21: 113–116 DOI: 10.1007/s00355-003-0204-3 This paper is drafted during my visit to the City University of Hong Kong late in 2001 and revised during my visit to the National University of Singapore in 2002. I am particularly grateful Professors Eden Yu and Euston Quah. The motivation for writing this paper is sparked by my drafting of the theme paper on welfare economics and sustainable development, published as Ng and Wills (2002), for UNESCO and EOLSS. the welfare value of the most distant future. The objective function should be