Evidence, probability, and relative plausibility: A response to Aitken, Taroni, and Bozza

Abstract

A paradigm shift is occurring in legal epistemology, replacing probability theory as the best explanation of juridical proof with a form of explanationism that has come to be known as the “ relative plausibility ” theory (see Allen and Pardo, 2019a). The probabilistic paradigm saw the common law legal systems as one large probabilistic event best explainable by reference to the probability calculus. The primary suc-cesses of that approach were to offer widely accepted explanations of burdens of persuasion as probabilistic thresholds and the meaning of the legal concepts of relevance and probative value. After a remarkable burst of enthusiasm reached its apex in the latter part of the twentieth century, dif fi culties began to be perceived — irritants in the language of Thomas Kuhn — that could not easily be accommo-dated within the reigning paradigm. As Kuhn observed and predicted, painting on a much larger and more important canvas than legal epistemology, the initial reaction of the adherents to the reigning paradigm is to attempt to explain away irritants, but in this case the irritants also led to new theorizing about the object of inquiry. That initial theorizing evolved over time into an explanation of common law legal systems that preserves a place for probabilistic reasoning but is dominated by the idea that the parties create and liti-gate alternative explanations for the events under consideration. The fact- fi nder (judge or jury) weighs their various merits and decides between them, or in their light creates the fact- fi nder ’ s own explanation of what happened — and that explanation wins the day. 1