New physical constraints emerged in the 20th century and are changing the decision criteria used until now. Two optimisation problems are equivalent: (1) maximising discounted utility with a long-run survival constraint and (2) maximising a new type of utility that treats the present and future...

We are interested in three related questions:(1) How should accounting prices be estimated?(2) How should we evaluate policy change in animperfect economy? (3) How can we check whetherintergenerational well-being will be sustainedalong a projected economic programme? We do notpresume that the...