Abstract: A growing body of psychological and neuroscientific research links dual-process theories of cognition with moral reasoning (and implicitly to legal reasoning as well). The relevant research appears to show that at least some deontological judgments are connected with rapid, automatic, emotional processing, and that consequentialist judgments (including utilitarianism) are connected with slower, more deliberative thinking. These findings are consistent with the claim that deontological thinking is best understood as a moral heuristic – one that generally works well, but that also misfires. If this claim is right, it may have large implications for many debates in politics, morality, and law, including those involving the role of retribution, the free speech principle, religious liberty, the idea of fairness, and the legitimacy of cost-benefit analysis. Nonetheless, psychological and neuroscientific research cannot rule out the possibility that consequentialism is wrong and that deontology is right. It tells us about the psychology of moral and legal judgment, but it does no more. On the largest questions, it leaves moral and legal debates essentially as they were before.