Judge Jack B. Weinstein argued quite some time ago that when counsel and court weigh the relevance of evidence, its probative value, and the question of undue prejudice, both reason and intuition must serve as the guide to the resolution of such questions. This position has always seemed to me to be eminently sensible. I mention this now only because a few legal scholars continue to take extreme positions on the question of the role of intuition and rational analysis in the assessment of evidence. Some legal scholars seem to assert that only intuition and ineffable common sense can serve to resolve disputes about matters such as probative value, while a few other scholars seem to go to the other extreme by suggesting that only rational analysis provides answers. My own view is that reason and rational analysis have an important role to play -- or we are justified in hoping and supposing that they play a useful role -- but that explicit rational analysis alone can only rarely provide the solution to an inferential problem. This is because any real-world assessment of evidence by the organism known as homo sapiens necessarily involves a wide variety of complex perceptual and information processing mechanisms that operate at a subconscious level, largely out of view of the mind's eye. Quite some time ago -- more than a century ago -- the "German polymath" Hermann von Helmholtz (1821-1894) uttered the dictum that perception is "unconscious inference." While there have been some occasional challenges to this hypothesis -- mainly by behaviorally-inclined psychologists who, like B.F. Skinner, seem anxious to deny the existence of "mental states" --, Helmholtz's dictum seems true: perceptual processes, processes that may not seem "rational" or "cognitive," in fact employ complex information processing procedures that seem to have a great deal of "logic" and "reason" in them. See, e.g., the many interesting recent studies of the nature of the logic that informs or underlies visual perception: Richard L. Gregory, "Knowledge in Perception and Illusion"; Daniel Kersten, "What Is the Visual System Like?"; Shimon Edelman, "Visual Perception" (including entries on "visual performance" and "visual competence" -- and much,much more).
So what? What does this stuff about the (supposed) "logic of perception" have to do with the price of tea in China -- or with the structure and nature of inference and proof in litigation?
This: The premise that there is a great deal of logic in our perceptual and subconscious processes suggests, on the one hand, that rational analysis has its uses, and, on the other hand, its limits. We must be modest in our expectations of the powers of explicit rational analysis of evidence, but we are also entitled to think, believe, or hope that rational analysis is occasionally able to bring features of inferential problems and inferential processes to the mind's eye, with the possible result, at least occasionally, that our submerged and tacit cognitive and perceptual processes work somewhat better than they otherwise would have worked.