Title Pending 16684

What do judges know, or think they know? What do judges not know, and not know that they do not know? When and why do judges sort themselves into competing tribes? The answer is that like everyone else, judges are part of epistemic communities. Consider some illustrations. In the last two decades, there has been an extraordinary outpouring of careful historical work on two of the most fundamental questions in constitutional law: (1) whether Congress may delegate open-ended discretionary power to the executive branch (or others) and (2) whether Congress may restrict the presidents power to remove high-level officials in the executive branch. The best reading of the new evidence is that there was no robust nondelegation doctrine during the founding period, if there was a nondelegation doctrine at all. Though the issue is closer, the best reading of the new evidence is that during the founding period, the Constitution was understood to authorize Congress to restrict the presidents power of removal, even over principal officers (with important qualifications). What is remarkable is that in both contexts, no originalist on the Court has been convinced by the relevant evidence, or even seriously grappled with it. There are three plausible explanations for the apparent impotence of historical evidence in this context (and others). The first points to optimal search, and hence to simple lack of awareness of the relevant evidence. The second is Bayesian and spotlights rational updating. The third points to motivated reasoning. All three accounts offer lessons for lawyers and others seeking to marshal historical or other evidence to disrupt engrained judicial beliefs.