Trial by mathematics--reconsidered

Abstract

In 1970, Michael O. Finkelstein (with William B. Fairley) proposed that under some circumstances a jury in a criminal trial might be invited to use Bayes' Theorem to address the issue of the identity of the criminal perpetrator. In 1971, Laurence Tribe responded with a rhetorically powerful and wide-ranging attack on what he called 'trial by mathematics'. Finkelstein responded to Tribe's attack by further explaining, refining and defending his proposal. Although Tribe soon fell silent on the use of mathematical and formal methods to dissect or regulate uncertain factual proof in legal proceedings, the Finkelstein-Tribe exchange precipitated a decades-long debate about trial by mathematics. But that debate, which continues to this day, became generally unproductive and sterile years ago. This happened in part because two misunderstandings plagued much of the debate almost from the start. The first misunderstanding was a widespread failure to appreciate that mathematics is part of a broader family of rigorous methods of reasoning, a family of methods that is often called 'formal'. The second misunderstanding was a widespread failure to appreciate that mathematical and formal analyses (including analyses that use numbers) can have a large variety of purposes. Before any further major research project on trial by mathematics is begun, interested researchers in mathematics, probability, logic and related fields, on the one hand, and interested legal professionals, on the other hand, should try to reach agreement about the possible distinct purposes that any given mathematical or formal analysis of inconclusive argument about uncertain factual hypotheses might serve. The article lists some of those possible purposes. Language: en