Factfinding Deconstructed Logically

Multivalent beliefs can be best understood if seen in action, as the factfinder processes evidence and evaluates proof. Before viewing them in action, though, one must dissect the stage of factfinding into two distinct phases: (1) processing each item of evidence by connecting it to a necessary fact before aggregating those connections to form a belief in the fact, and then (2) evaluating the beliefs in each of those necessary facts against the standard of proof. This fairly long chapter’s study of examples manages to lay bare our intuitive ways both of linking an evidential item to a belief through a chain of inferences and of somehow averaging the various items of evidence to produce overall beliefs in each of the elemental facts. Likewise, multivalent belief theory works well for analyzing our intuitive way of evaluating the resultant beliefs against the standard of proof. Section 5.1: The initial phase of factfinding entails the processing of the evidence. First, the factfinder should connect each item of evidence to a fact to be proved, or element, by constructing a chain of inferences. Second, the factfinder must aggregate the probative force of all the items of evidence that bear on any one element. Third, the factfinder may choose to combine the elements of claim or affirmative defense, but the better approach is to proceed directly to applying the appropriate standard of proof to each element. In sum, the factfinder should abductively construct a chain of inferences to produce a belief function for each item of evidence bearing on an element, and then weight and average them to produce for each element a composite belief function ready for applying the element-by-element standard of proof. Section 5.2: The final phase of factfinding entails evaluating the evidence as proof against some standard of proof. The preliminary topics of the burdens of proof translate readily and advantageously into the terms of belief functions, as does the standard of proof itself. First, the burden of production, which effectuates multiple process and outcome values, means that the decisionmaker or reviewer must patrol the sufficiency of the evidence to ensure that there is rationally enough of a belief to warrant the factfinder’s applying the burden of persuasion. Second, any view of the burden of persuasion that rests on probabilities should yield to a reformulation along the lines of belief functions. Third, on the key topic of the standards of proof, belief functions make indispensable contributions to understanding. For example, preponderance of the evidence is best understood as providing that the burdened party should win if and only if Bel(a) > Bel(not-a). The higher standards of proof demand a greater predominance of belief in relation to disbelief.