Book excerpt: There has been substantial debate in the legal academy centered on the questions of whether universal moral intuitions exist and, if so, whether these intuitions have a privileged normative status, a debate both reflecting and partly reinterpreting classical jurisprudential debates about the existence of “natural law” and “natural rights.” There is a strong but underappreciated homology between the debates about the nature and quality of intuitive moral reasoning, and debates, associated with the Heuristics and Biases (H&B) school on the one hand and the “Fast and Frugal” (F&F) school on the other, about the nature and quality of our capacity to make self-interested decisions (decisions requiring both factual and a-moral evaluative judgment and decision making ability. There are those in the legal academy, most prominently Cass Sunstein, who accept that people indeed often have strong moral intuitions but believe these predispositions deserve little or no normative deference because the intuitions frequently merely reflect the use of inapt rules of thumb. Others, most prominently John Mikhail, believe people readily make non-reflective moral judgments that we cannot readily explain or justify logically that are grounded in our capacity to process a quite small number of critical features of a decision situation in precisely the way that F&F theorists believe we make most judgments. I explore the degree to which some of the virtues, and, more importantly, most of the problems, in both Sunstein's and Mikhail's work are the features and shortcomings that have bedeviled the work of each of the schools on heuristic reasoning.