Evidence Law—What For?

My book, Foundations of Evidence Law, was published thirteen years ago. Between then and now, the book has been reviewed and discussed on multiple occasions. Most of its critics have agreed with my core insight that evidentiary rules—all of them, and not just burdens and standards of proof—allocate the risk of error in factfinding to plaintiffs, prosecutors, and defendants (civil and criminal). This insight vindicated the conventional common-law system of proof that employs different admissibility and corroboration requirements to preselect evidence for trials. If evidentiary rules allocate risk of error, who should get to decide how to allocate that risk and the resulting undeserved denial of freedom or entitlement? Why allow trial judges and jurors to allocate this risk as they deem right? Why not give this power to publicly visible and politically accountable actors such as supreme courts and legislators? Moreover, why not grant individuals constitutional rights against risks of error? These fundamental questions escaped the attention of Bentham and contemporary opponents of the common law system of proof. Bentham and his followers have argued that lawmakers will do well to abolish all evidence selection rules and let factfinders evaluate all relevant evidence. This abolitionist claim alluded to a set of virtues that included truth, simplicity, cost-savings, and uniformity. Arguably, by considering all relevant evidence, factfinders will maximize their chances to uncover the truth. Trials without evidentiary rules will also become uncomplicated and inexpensive. Finally, doing away with evidence selection rules will align the American trial system with much the rest of the world. My book has refuted the abolitionist claim by showing that these virtues are false. Bentham’s claim that augmentation of relevant information makes discovery of the truth more likely has received a near-uniform endorsement from evidence scholars. Whether this claim is correct, however, can only be determined by the principles of epistemology and logic. These principles prove that the “more information, more truth” argument is patently false. Augmentation of relevant information, without more, does not make the factfinder more informed. The factfinder becomes more informed when the information she receives is trustworthy, rather than simply relevant to her decision. Any piece of (first-order) information that factfinders receive under conditions of uncertainty consequently requires supplemental (second-order) information concerning its trustworthiness. This second-order information needs to be trustworthy as well, which calls for yet another set of supplemental (third-order) information, and so on. To avoid this infinite and fruitless inquiry, factfinders must preselect their evidence. They must take into consideration evidence likely to improve their decisions while ignoring all other evidence. Any such selection of evidence allocates the risk of error and the accompanying prospect of an undeserved denial of freedom or entitlement to one party or another. How to allocate such risks is an issue of political morality. Individual judges and jurors should have no authority to decide this issue as they deem right. Under the conventional power structure of modern democracies, such issues ought to be determined by common law precedent, statute, and constitution. The simplicity of “free proof” is also an illusion. Trials without evidentiary rules will not turn into an uncomplicated affair by themselves. They would become uncomplicated only if litigants avoid making claims with regard to evidentiary uncertainty and the consequent need to allocate the risk of error one way or another. There is, however, no rational reason for suppressing such claims. Adjudicative factfinding is not naturally simple. Falsely pretending that it is would suppress the question about the desired allocation of the risk of error, but would not make this question disappear. As far as cost is concerned, the abolitionists’ exclusive focus on the expenses generated by the evidentiary rules is wrongheaded. For reasons well familiar to any contemporary economist, cost questions should be resolved not only by what one pays, but also by what one gets in return. When an evidentiary rule helps the legal system allocate the risk of error in a socially desirable fashion, policymakers should juxtapose this benefit against the rule’s cost. If the benefit is greater than the cost, the rule becomes socially desirable even when its standalone cost is high. More fundamentally, the factfinding system would do well to reduce the cost of errors and error avoidance as a total sum. Allowing individual judges and jurors to allocate the risk of error as they deem right will not meet this target. Among the abolitionists’ claims, the uniformity argument is probably the weakest. Those who believe in this argument implicitly prefer an intellectual cartel to intellectual competition. My book theorized the Anglo-American way of dealing with evidence, uncertainty, and the risk of error. Calling this way (pejoratively) “American exceptionalism” doesn’t advance the conversation. My theory explains, justifies and commends the common law system of factfinding. Yet, it does not claim that there can be no better system. Allocation of the risk of error and the consequent prospect of denying a person her freedom or entitlement crucially depends on societal preferences and values. These preferences and values need not be universal.