場所：Online Seminar in Zoom（下記参照）
タイトル：Treating future people impartially implies avoiding future lives with low well-being (jointly with Geir B. Asheim and Stéphane Zuber)
要旨：It has been claimed that climate policies can be evaluated by the Pareto principle. However, climate policies lead to different identities and different numbers of future people. Even if one assumes that the number of future people is infinitely countable independently of policy choice, the problem is that there exists no natural one-to-one correspondence between the components of the compared alternatives. We use this non-existence as a motivation for insisting on impartiality in the sense of Strong anonymity. Strong anonymity is incompatible with Strong Pareto. The paper re-examines this incompatibility and investigates how far a Paretian principle can be extended without contradicting Strong anonymity. We show that Strong anonymity combined with four rather innocent axioms has two consequences: (i) There is sensitivity for a person's well-being if and only if a co-finite set of people are more than an ε (>0) better than this person, and (ii) adding people to the population cannot have positive social value.