Some ethicists try to settle moral disagreement by ruling out particular types of moral reasoning on the basis of cognitive scientific evidence. We argue that the cognitive science of reasoning is not well-suited to this Archimedean role. Through discussion of several influential research programs, we show that such attempts tend to either fail to be Archimedean (by assuming controversial moral views) or fail to settle disagreement (by getting caught up in unsettled debates about rationality). We speculate that these outcomes reflect a fundamental sort of normative disagreement, which can be reshuffled to the domains of morality or rationality, but cannot be avoided.
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