Evidence and Proof, Doctrinal Issues In

The “New Evidence Scholarship”

Some law professors in English-speaking countries and continental Europe subscribe to the so-called “new evidence” scholarship, which argues that legal studies should include the processes by which humans do or ought to reason about and reach conclusions concerning the weight and meaning of evidence. Law should tap the rich vein of information in disciplines such as logic, philosophy, and psychology that have been studying the matter for years.

This new scholarship partly returns to the beliefs of the renowned American evidence scholar John Henry Wigmore (1863–1943). In The Principles of Judicial Proof (1913), he set forth an elaborate system of logic for analyzing evidence. His approach proved too complex for practical use, but several of the new scholars purported to make it more accessible. Some of their approaches developed in connection with the analysis of intelligence data in national security matters.

Probability

Part of the new evidence debate is whether probability theory should be included in evidence courses and in trials. Scholars agree that some notion of probability is necessarily involved in any deliberation about what to conclude from evidence. English law requires civil plaintiffs' verdicts to be based on “the balance of probabilities.” American law uses “preponderance of the evidence” instead. Both standards mean the essential facts must be proved more probable than not. In criminal cases, the standard is “beyond a reasonable doubt.” This does not require certitude either—only a very high order of probability. Furthermore, U.S. evidence rules declare evidence relevant if it has any tendency to make a matter of consequence to the litigation “more probable or less probable than it would be without the evidence” (Federal Rules of Evidence [FRE] 401).

Thus, fact finders necessarily consider probability. A jury may have to assess the probability that one who writes a love letter (introduced in evidence in a murder trial against the writer) might kill the spouse of the object of his love. Or the probability that the defendant's attempted suicide in jail while awaiting trial indicates consciousness of guilt of the charged offense. Or the probability that two different couples would have the same ten identical characteristics shown to be possessed by both the couple at the scene of the robbery and the couple on trial for the robbery.

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