We consider collective decisions under uncertainty, when agents have "generalized Hurwicz" preferences, a broad class allowing many different ambiguity attitudes, including subjective expected utility preferences. We consider sequences of acts that are “almost-objectively uncertain” in the...

In this study, we develop a model of social choice over lotteries, where people’s psychological characteristics are mutable, their preferences may be incomplete, and incomplete or noisy interpersonal comparisons of well-being are possible. Formally, we suppose individual preferences are...

We adopt an ‘epistemic’ interpretation of social decisions: there is an objectively correct choice, each voter receives a ‘noisy signal’ of the correct choice, and the social objective is to aggregate these signals to make the best possible guess about the correct choice. One epistemic...

`Relative Utilitarianism' (RU) is a version of classical utilitarianism, where each person's utility function is rescaled to range from zero to one. As a voting system, RU is vulnerable to preference exaggeration by strategic voters. The Groves-Clarke Pivotal Mechanism elicits truthful...

The Clarke Pivotal Voting Mechanism (CPVM) elicits truthful revelation of utility functions by requiring any `pivotal' voter to pay a monetary `Clarke tax'. This neglects wealth effects and gives disproportionate power to rich voters. We propose to replace the `Clarke tax' with a lottery,...

Some social choice models assume that precise interpersonal comparisons of utility (either ordinal or cardinal) are possible, allowing a rich theory of distributive justice. Other models assume that absolutely no interpersonal comparisons are possible, or even meaningful; hence all...

Given a set of propositions with unknown truth values, a `judgement aggregation rule' is a way to aggregate the personal truth-valuations of a set of jurors into some `collective' truth valuation. We introduce the class of `quasimajoritarian' judgement aggregation rules, which includes majority...

Let S be a set of logically related propositions, and suppose a jury must decide the truth/falsehood of each member of S. A `judgement aggregation rule' (JAR) is a rule for combining the truth valuations on S from each juror into a collective truth valuation on S. Recent work has shown that...

Given a bargaining problem, the `relative utilitarian' (RU) solution maximizes the sum total of the bargainer's utilities, after having first renormalized each utility function to range from zero to one. We show that RU is `optimal' in two very different senses. First, RU is the maximal element...