From Separability to Unweighted Sum: A Case for Utilitarianism

After reviewing three basic problems of normative social choice (What information? How to obtain? Which SWF?) and two full and two partial compelling cases for utilitarianism (defined as "social welfare is the unweighted sum of individual utilities"), an argument is advanced to supplement the two partial cases to make them full. Basically, a compelling individualism-type axiom leads us to (social welfare as an) unweighted sum (of individual utilities), given the separability result already obtained in the two partial cases towards utilitarianism. Apparently compelling objections to utilitarianism are explained to be not really acceptable.