This Article identifies a discrepancy between law and epistemology and proposes a way to fix it. Our legal system relies on decisions of multimember tribunals, which include juries, state and federal appellate courts, and supreme courts. Members of those tribunals often disagree with each other on matters of fact. The system settles such disagreement by applying head-counting rules: the unanimity or supermajority requirement for jury verdicts and the majority rule for judges’ decisions. Under these rules, jurors can return an agreed-upon verdict even when their reasons for supporting the verdict are inconsistent with one another. Similarly, judges are authorized to deliver any decision so long as it is supported by a majority of the panel. Disagreements among judges and jurors are consequently ironed out instead of being accounted for as a factor that reduces the reliability of the final decision.
By adopting these rules, our legal system allows jurors to convict the defendant when six of them believe the incriminating account provided by one witness, while rejecting as non-credible the testimony of another prosecution witness, and the remaining six jurors form a diametrically opposite view of the two witnesses’ credibility. Moreover, the system authorizes appellate courts to determine by a narrow 2-1 majority that a violation of the accused’s constitutional trial right was “harmless beyond a reasonable doubt.” Likewise, it accords the status of an unreservedly binding precedent to a 5–4 decision of the United States Supreme Court that determines the meaning of a statutory or constitutional provision.
These rules are fundamentally incompatible with the epistemological principles of rational fact-finding. The epistemology of disagreement maintains that when a person makes a factual finding and then realizes that an equally informed, competent, and honest individual—an “epistemic peer”—arrived at a different conclusion, based on the same information, she ought to scale down her level of confidence in her own opinion. A peer’s disagreement is evidence writ large that a person cannot rationally ignore or discount. Rather, it must be given weight and cause one to revisit her original opinion.
This epistemological principle has far-reaching implications for the law. For example, a guilty verdict rendered by a jury cannot be considered unanimous when the underlying reasons contradict each other; a dissent by a single appellate judge should preclude a guilty sentence under the “beyond a reasonable doubt” standard; and a precedent laid down by a narrow majority of the Supreme Court should remain open to reconsideration.
Law and the Epistemology of Disagreements, 96 Washington University Law Review 51-103 (2018) download
THE NEW DOCTRINALISM: IMPLICATIONS FOR EVIDENCE THEORY
This Article revisits and refines the organizing principles of evidence law: case-specificity, cost-minimization and equal-best. These three principles explain and justify all admissibility and sufficiency requirements of the law of evidence. The case-specificity principle requires that factfinders base their decisions on the relative plausibility of the stories describing the parties’ entitlement-accountability relationship. The cost-minimization principle demands that factfinders minimize the cost of errors and the cost of avoiding errors as a total sum. The equal-best principle mandates that factfinders afford every person the maximal feasible protection against risk of error while equalizing that protection across the board.
The Article connects these principles to the irreducibly second-personal structure of legal doctrine (that tracks Stephen Darwall’s celebrated account of morally justified claims). Under this structure, the plaintiff’s (or the prosecutor’s) authority to extract compensation from (or impose punishment on) the defendant critically depends on the trustworthiness of the individual infringement allegations that make the defendant accountable to the plaintiff (or the prosecutor). Evidentiary rules fit into this second-personal framework only when they promote case-specificity, cost-minimization or equal-best. Reform proposals that favor different rules are fatally disconnected from that framework and are therefore ill-conceived.
Based on this observation, I criticize three powerful accounts of evidence law that rely, respectively, on economics, probability theory, and morality. These accounts include Louis Kaplow’s theory of the burden of proof; the claim made by Daniel Kahneman and Amos Tversky that factfinders’ deviations from mathematical probability are irrational; and Ronald Dworkin’s distinction between accidentally and deliberately imposed risks of error. These accounts break away from our second-personal system of entitlements and liabilities; and by doing so, they create a methodologically impermissible disconnect between rules of evidence and substantive laws.
The New Doctrinalism: Implications for Evidence Theory, 163 University of Pennsylvania Law Review 2085-2017 (2015) download
Why set up evidentiary rules rather than allow factfinders to make decisions by considering all relevant evidence? This fundamental question has been the subject of unresolved controversy among scholars and policymakers since it was raised by Bentham at the beginning of the nineteenth century. This Article offers a surprisingly straightforward answer: An economically minded legal system must suppress all evidence that brings along a negative productivity-expense balance and is therefore inefficient. Failure to suppress inefficient evidence will result in serious diseconomies of scale.
To operationalize this idea, I introduce a “signal-to-noise” method borrowed from statistics, science, and engineering. This method focuses on the range of probabilities to which evidence falling into a specified category gives rise. Specifically, it compares the average probability associated with the given evidence (the “signal”) with the margins on both sides (the “noise”). This comparison allows policymakers to determine the signal-to-noise ratio (SNR) for different categories of evidence. When the evidence’s signal overpowers the noise, the legal system should admit the evidence. Conversely, when the noise emanating from the evidence drowns the signal, the evidence is inefficient and should therefore be excluded. I call this set of rules “the SNR principle.” Descriptively, I demonstrate that this principle best explains the rules of admissibility and corroboration by which our system selects evidence for trials. Prescriptively, I argue that the SNR principle should guide the rules of evidence-selection and determine the scope of criminal defendants’ constitutional right to compulsory process.
Inefficient Evidence, 66 Alabama Law Review 423-470 (2015) download
THE DISTORTIONARY EFFECT OF EVIDENCE ON PRIMARY BEHAVIOR In this Essay, we analyze how evidentiary concerns dominate actors’ behavior. Our findings offer an important refinement to the conventional wisdom in law and economics literature, which assumes that legal rules can always be fashioned to achieve socially optimal outcomes. We show that evidentiary motivations will often lead actors to engage in socially suboptimal behavior when doing so is likely to increase their likelihood of prevailing in court. Because adjudicators must base decisions on observable and verifiable information—or, in short, evidence—rational actors will always strive to generate evidence that can later be presented in court and increase their chances of winning the case regardless of the cost they impose on third parties and society at large. Accordingly, doctors and medical institutions will often refer patients to undertake unnecessary and even harmful examinations just to create a record that they went beyond the call of duty in treating them. Owners of land and intellectual property may let harmful activities continue much longer than necessary just to gather stronger evidence concerning the harm they suffer. And even the police will often choose to allow offenders to carry out crimes in order to improve the chance of a conviction. The effect we identify is pervasive. It can be found in virtually all areas of the law. Furthermore, there is no easy way to eliminate or correct it. It should be noted, however, that the evidentiary phenomenon we discuss also has a positive side effect: it reduces adjudication costs for judges and juries and improves the accuracy of court processes. In some cases, this improvement will exceed the social cost stemming from actors’ suboptimal behavior. In other contexts, however, the social cost will far outweigh the benefit.
The Distortionary Effect of Evidence on Primary Behavior, 124 Harvard Law Review 518-548 (2010) (with Gideon Parchomovsky) download
EVIDENCE LAW ALLOCATES THE RISK OF ERROR RATHER THAN FACILITATES ASCERTAINMENT OF THE TRUTH Evidence rules are not geared towards ascertainment of the truth. Instead, they allocate the risk of error in fact-finding. This is what evidentiary rules also should be doing. How to allocate the risk of error properly is a difficult question that crucially depends on political morality. I develop three fundamental principles for allocating the risk of error: the cost-efficiency principle which applies across the board; the equality principle which applies in civil litigation; and the equal-best principle which applies in criminal trials. The cost-efficiency principle demands that fact-finders minimize the total cost of errors and error-avoidance. Under the equality principle, fact-finding procedures and decisions must not produce an unequal apportionment of the risk of error between the claimant and the defendant. This risk should be apportioned equally between the parties. The equal-best principle sets forth two conditions for justifiably convicting and punishing a defendant. The state must do its best to protect the defendant from the risk of erroneous conviction and must not provide better protection to other individuals.
The equal-best and equality principles branch into more specific evidentiary rules that respond to the "maximal individualization" criterion. Under this criterion, fact-finders can make no adverse finding against a litigant unless the evidence supporting that finding was subjected to—and survived—maximal individualized testing. The cost-efficiency principle, however, sometimes overrides this criterion on special policy grounds that call for adoption of different evidentiary rules.
This system justifies and explains the rules that control the admissibility and sufficiency of evidence.
THE ANTI-POOLING JUSTIFICATION OF THE FIFTH AMENDMENT PRIVILEGE AGAINST SELF-INCRIMINATION (THE RIGHT TO SILENCE) The right to silence has a solid consequentialist justification. The conventional perception of this right -- that it impedes the search for truth and thus helps only criminals -- is mistaken. The right to silence helps triers of fact to distinguish between innocent and guilty defendants. A guilty suspect's self-interested response to questioning can impose externalities, in the form of wrongful conviction, on innocent suspects and defendants who tell the truth but cannot corroborate their stories. Absent the right to silence, guilty suspects and defendants would make false exculpatory statements if they believed that their lies were unlikely to be exposed. Aware of these incentives, triers of fact would rationally discount the probative value of uncorroborated exculpatory statements at the expense of innocent defendants who could not corroborate their true exculpatory statements. Because the right to silence is available, innocent defendants tell the truth while guilty defendants rationally exercise the right when they fear that lying is exceedingly risky. Thus, guilty defendants do not pool with innocents by lying; and as a result, triers of fact do not wrongfully convict innocent defendants.
The Right to Silence Helps the Innocent: A Game-Theoretic Analysis of the Fifth Amendment Privilege, 114 Harvard Law Review 430 (2000) (with Daniel Seidmann) download
For my forthcoming response to the critics of this article, click HERE
THE OVERENFORCEMENT PARADIGM Overenforcement of the law occurs when the total sanction suffered by the violator of a legal rule exceeds the amount optimal for deterrence. Overenforcement sometimes generates overdeterrence that cannot be remedied through the adjustment of substantive liability standards or penalties in light of operational and expressive constraints. When that happens, the legal system can counteract the effects of overenforcement by adjusting evidentiary or procedural rules to make liability less likely (ex ante). This framework -- the overenforcement paradigm -- illuminates previously unnoticed features of various evidentiary and procedural arrangements. It also provides a useful analytical and prescriptive tool for creating balanced incentives in cases in which overenforcement is present.
Overenforcement, 93 Georgetown Law Journal 1743 (2005) (with Richard A. Bierschbach) download
MEDIATING RULES IN CRIMINAL LAW This article challenges the conventional divide between substantive criminal law theory, on the one hand, and evidence law, on the other, by exposing an important and unrecognized function of evidence rules in criminal law. Throughout the criminal law, special rules of evidence work to mediate conflicts between criminal law’s deterrence and retributivist goals. They do this by skewing errors in the actual application of the substantive criminal law to favor whichever theory has been disfavored by the substantive rule itself. The mediating potential of evidentiary rules is particularly strong in criminal law because the substantive law’s dominant animating theories – deterrence and retributivism – respond asymmetrically to the workings of those rules. We analyze the features of “mediating rules,” explore their effects across a range of substantive areas, and offer a tentative normative assessment of their role in the criminal law system.
Mediating Rules in Criminal Law, 93 Virginia Law Review 1197(2007) (with Richard A. Bierschbach) download
CONSTITUTIONAL EVIDENCE LAW This Article identifies the causes and consequences of a puzzling asymmetry in constitutional law. Of the three facets of adjudicative fact-finding—evidence, procedure, and rules of decision—only two are constitutionalized. Constitutional law regulates procedural and decisional rules—not whether the evidence that fact-finders use is adequate. Allocation of the risk of error by procedures and decisional rules—formulated as burdens of proof—is subject to constitutional scrutiny. Allocation of the risk of error by the rules of evidential adequacy, however, is free from that scrutiny. This constitutional asymmetry is puzzling because all risk-allocation impacts court decisions and, consequently, whether a person is deprived erroneously of her liberty or property. This Article explains this asymmetry in the informal constitutionalization of evidence—a phenomenon that implicates three dynamics of power and culture. First, state evidence rules generally align with the Supreme Court’s agenda for risk-allocation. Second, when those rules do deviate from the Court’s agenda to promote local interests, they do not do so overtly. Finally, a state rule’s alignment with a federal rule of evidence guarantees its constitutionality. This informal order reflects a series of implicit, but credible understandings between state courts and the Supreme Court. This Article identifies and illustrates these understandings.
Constitutional Evidence Law, 61 Vanderbilt Law Review 65-124 (2008) download
THE "BLUE CAB" EXPERIMENT: ARE FACT-FINDERS "PROBABILISTICALLY CHALLENGED"? They are not. The experiment is methodologically deficient, as is the behavioral economics' assumption that one needs to conceptualize probabilities in the Pascalian way in order to be rational. A Liberal Challenge to Behavioral Economics: The Case of Probability, 2 New York University Journal of Law & Liberty 531 (2007) (Symposium on Behavioral Law & Economics' Challenge to the Classical Liberal Program) download
TORTS AND INNOVATION This Essay exposes and analyzes a hitherto overlooked cost of the current design of tort law: its adverse effect on innovation. Tort liability for negligence, defective products, and medical malpractice is determined by reference to custom. We demonstrate that courts’ reliance on custom and conventional technologies as the benchmark of liability chills innovation and distorts its path. Specifically, the recourse to custom taxes innovators and subsidizes replicators of conventional technologies. We explore the causes and consequences of this phenomenon and propose two possible ways to modify tort law in order to make it more welcoming of innovation.
Torts and Innovation, 107 Michigan Law Review 285-315 (2008) (with Gideon Parchomovsky) download