The Paradoxes of Legal Proof: A Critical Guide

58 Pages Posted: 11 Dec 2018 Last revised: 18 Feb 2019

Date Written: January 2019


For several decades, a variety of paradoxes have fascinated and frustrated legal scholars and courts discussing evidence, procedure, and legal proof. These paradoxes concern issues such as statistical evidence, burdens and standards of proof, and rules for jury verdicts. As with other types of paradoxes, the paradoxes of legal proof raise fundamental issues and assumptions. In the legal context, the issues and assumptions are not merely of theoretical interest; they also have significant practical implications at trial and, indeed, throughout the processes of civil and criminal litigation. At the same time, there remains very little agreement about any of the paradoxes, and the issues they raise remain highly contested.

This Article explores the different types of legal-proof paradoxes and the connections between them. In analyzing the structure of the paradoxes, the Article makes three contributions. First, it explains the practical significance of the paradoxes and why they raise fundamental issues for evidence law and for civil and criminal procedure. Second, it reveals the necessary connections between the different types of paradoxes and the ways in which one type of paradox has implications for the others. These unexplored connections help to explain why individual paradoxes have resisted consensus and continue to prompt discussion and disagreement—the paradoxes are too often treated as isolated problems to be “solved” without appreciating how the underlying issues relate to issues raised by the other paradoxes. Third, the analysis clarifies the primary source of confusion for each type of paradox: namely, the popular but mistaken assumption that standards of proof are probabilistic thresholds. Abandoning this spurious assumption provides a number of salutary theoretical and practical consequences, including greater clarity of the legal issues underlying the paradoxes; a better explanation of legal doctrine; and an improved understanding of the manifold litigation issues that depend on the legal-proof process.

Keywords: evidence, probability, explanation, statistical evidence, blue bus, gatecrashers, standards of proof, preponderance of evidence, beyond a reasonable doubt, conjunction paradox, verdicts

Suggested Citation

Pardo, Michael S., The Paradoxes of Legal Proof: A Critical Guide (January 2019). Boston University Law Review, Vol. 99, 2019, U of Alabama Legal Studies Research Paper No. 3293023, Available at SSRN:

Michael S. Pardo (Contact Author)

Georgetown University Law Center ( email )

600 New Jersey Avenue, NW
Washington, DC 20001
United States


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