This first part of this book is an introduction to the approach that is developed. Its first aim is to help the reader understand where the approach lies in the broad field of normative economics; the first chapter reviews the various subdomains of the field to highlight the main differences. Its main point is to show that our approach is the only one that combines various features that are scattered in various classical approaches. Fundamentally, this approach opens a working space at the intersection of social choice theory and fair allocation theory. Like the former, it constructs rankings of all possible alternatives; like the latter, it involves fairness principles about resource allocation rather than interpersonal comparisons of utility; like both theories, it puts the Pareto principle, the ideal of respecting individual preferences, first in the order of priorities. The expression “fair social choice” is often used as a name for the approach.

The second and third chapters introduce general results that appear to be common to all models that have been studied so far. These results are striking and somewhat counterintuitive. The first is that there is a tension between the Pareto principle and the deceptively simple idea that an agent who has more in all dimensions than another, such as one who consumes more of all commodities, is necessarily better off and should transfer some of the surplus to the other agent.