Utilitarianism is the most prominent family of social welfare functions. We present three new axiomatic characterizations of utilitarian (that is, additively separable) social welfare functions in a setting where there is risk over both population size and the welfares of individuals. First, we...

The expectation of a sum of utilities is a core criterion for evaluating policies and social welfare under variable population and social risk. Our contribution is to show that a previously unrecognized combination of weak assumptions yields general versions of this criterion, both in...