Unweighted benefit–cost analysis (BCA) based on aggregate willingness to pay might be, at long last, falling into disrepute, as it is widely recognized that it exhibits a bias toward the wealthy, and as alternatives are appearing more and more practicable. However, the choice of alternatives is often framed in terms of choosing an alternative metric to willingness to pay in money, such as willingness to pay in healthy life years, or a measure of subjective well-being. It is argued in this paper that (i) a simple summation of individuals’ willingness to pay in any numeraire (e.g., money, healthy life years) is bound to generate non-transitivity issues in a similar way as money-based BCA, and (ii) a metric such as subjective well-being involves distributional value judgments that are too specific to reflect the relevant spectrum in the public debate. The “orthodox” weighted BCA method, which links BCA to an underlying social welfare function, offers more flexibility and guarantees transitive choices. Fortunately, in some relevant cases, these various methods may provide similar results, and the main options currently proposed all give greater weight to the worse off in the population than does unweighted BCA.

We highlight a new paradox for the social evaluation of risk that bears on the evaluation of individual well-being rather than social welfare, but has serious implications for social evaluation. The paradox consists in a tension between rationality, respect for individual preferences, and a principle of informational parsimony that excludes individual risk attitudes from the assessment of riskless situations. No evaluation criterion can satisfy these three principles. This impossibility result has implications for the evaluation of social welfare under risk, especially when the preferences of some individuals are not known. It generalizes existing impossibility results, while relying on very weak principles of social rationality and respect for individual preferences. We explore the possibilities opened by weakening each of our three principles and discuss the advantages and drawbacks of these different routes.

The Repugnant Conclusion is an implication of some approaches to population ethics. It states, in Derek Parfit's original formulation,

The contributors to this symposium have brought up many important points in their discussions of five chapters of the Report, and we are very grateful to them. Since the authors of the chapters would be better able to respond to many of the specific comments, we will confine ourselves here to a brief discussion of a few major issues highlighted by the contributors. We are in particular inspired by the following comments: Alina Rocha Menocal's point about the role of the state and committed elites; James Deane's description of the deep transformation of the media scene by new forms of communication; Uma Rani's emphasis on the importance of structural transformation and social care policies; and Diana Alarcon's call for paying greater attention to different levels of development and to macroeconomic policy.

In 2014, the New York Times columnist Nicholas Kristof wrote: ‘Some of the smartest thinkers on problems at home and around the world are university professors, but most of them just don't matter in today's great debates … I write this in sorrow, for I considered an academic career and deeply admire the wisdom found on university campuses. So, professors, don't cloister yourselves like medieval monks – we need you!’ At that time, a group of academics were working to launch the International Panel on Social Progress, with the aim of preparing a report analysing the current prospects for improving our societies.1 It gathered about 300 researchers from more than 40 countries and from all disciplines of the social sciences, law and philosophy.