 Although the weak Pareto principle is arguably one of the least contentious ones of Arrow’s conditions, Sen (1970a) offered a critique of it that applies when the aggregation rule is interpreted not as a voting method, but as a social evaluation method which a social planner can use to rank social alternatives in an order of social desirability. Here, the alternatives are understood not as coarse-grained electoral options but as more richly specified states of society. Sen showed that, in this setting, the Pareto principle conflicts with a ‘liberal’ principle, which—he suggested—a social planner ought to respect.