The Structure of Proof in Modern Trials
University of Sydney, September 24-25, 2010
Workshop: 21st Century Challenges in Evidence Law: International and Comparative Perspectives
The structure of proof in modern trials cannot be ascertained solely by reference to logic, epistemology, and ontology; timeless logical, epistemological, and ontological principles alone cannot explain the features and workings of forensic proof at a particular time in a particular place. It is necessary to consider empirical fact and historical contingency. But a meaningful description of modern forensic proof – a description or account that amounts to more than a stultifying and largely-useless catalogue of contingent facts – cannot be constructed without reference to (valid) principles of logic, epistemology, and ontology. A meaningful account of proof in modern trials must rest on the interplay of timeless necessity and historical contingency – on the interplay of logic, epistemology, and ontology, on the one hand, and historical contingency, on the other hand.
In some instances the interplay of historically contingent matters and timeless necessities generates almost ineluctable implications for any system of forensic proof. For example, if a society or legal system values truthfinding to some degree, it is practically certain that (i) truthfinding cannot be the only objective of a trial (or any other legal proceeding) and (ii) the amount of time and resources that can devoted to truthfinding is limited rather than unlimited. Given the modern understanding of the character of human factual knowledge, it is almost equally certain that forensic proof can only aspire to produce probable knowledge. Furthermore, given the modern understanding of human cognition, it is practically certain that a society or legal system cannot and will not provide any legal actor (e.g., a judge, juror, or investigator) with an exhaustive set of explicit principles or rules for arriving at an optimal assessment of the probability of the truth or falsity of a factual hypothesis. (No one should expect that any legal system, whether in the near or distant future, will or can use a fully-autonomous robot or procedure to assess evidence.)
The interplay of historical contingency and timeless necessity generates further implications, many of which are little more than hints but are nevertheless useful and important. For example, the American system of forensic proof has the following striking features (among others): (i) extensive pretrial and prelitigation gathering, marshaling, and preparation of evidence; (ii) the gathering and submission of large quantities of small slivers of evidence; (iii) party domination of pretrial and trial evidentiary processes; (iv) extensive argument about evidence; and (v) the use of stories in argument about evidence. These features of American proof suggest (but do not prove) that American society or its legal system embraces the following plausible propositions – and these features of American proof suggest that the following propositions have considerable merit: (i) the deliberate search for and acquisition of relevant evidence generally improves the quality of decision making about the truth or falsity of uncertain facts; (ii) the quality of factfinding is better if there are collections of relevant fine-grained evidence than if the only available evidence is relatively coarse and undifferentiated; (iii) the quality of factfinding in adjudication depends on the quality of preadjudication evidentiary processes, and the quality of preadjudication evidentiary processes in turn depends on exploration of an “adequate” number of factual possibilities; (iv) rational argument about evidence is both possible and helpful; and (v) rational assessment of evidence requires synthesis – “holistic” thinking – as well as “analysis,” the dissection of clusters of evidence into parts. (If these last five propositions about the workings of inference seem self-evident to you, this may show that you have good sense – or that you have become acculturated into certain ways of thinking. In either case, such a reaction to the five propositions shows or suggests that the bramble-bush of real-world evidentiary processes is a good or essential source of insights into factual inference.)
The argument sketched above rests in part on the following two premises (for which support is available and some is adduced): (i) the human animal is an evolving intelligent organism and (ii) the human animal uses, should use, and must use both explicit and tacit methods of calculation and deliberation.