Proof Beyond a Reasonable Doubt Doesn’t Exist: Except as an Emergent Property of a Complex Adaptive System

The pursuit of knowledge is undergoing a transformation. Scientists and scholars are rejecting standard reductionist efforts, popularly captured by “the scientific method” and embracing the framework of complexity theory and complex adaptive systems. That framework is invaluable to understand both the law of evidence and the nature of Anglo-American legal systems. It also has significant implications for the ongoing debate over the concept of law. This Article demonstrates how “proof beyond a reasonable doubt” (BARD) does not exist in any knowable form, except as an emergent property of a complex adaptive system—the criminal process. First, what constitutes BARD will vary within any jurisdiction. BARD is a linguistically vague and indeterminate standard. Second, evidentiary and procedural regimes will differ from state to state and from country to country. Differences in such regimes will functionally affect what constitutes BARD. We demonstrate how plea bargaining, declination, and diversionary programs will affect what constitutes BARD by affecting the proportion of factually guilty and innocent defendants that proceed to trial (incidentally affecting any distribution of errors). Third, we account for and respond to how the debate surrounding BARD is imbued with a deterministic focus on solving what BARD is and should be, which has proven to be a futile quest. Scholars must embrace—not ignore—the complexity that permeates our evidentiary and procedural regimes.