Procedure's Magical Number Three: Psychological Bases for Standards of Decision

Abstract

So many procedural doctrines appear, after research and teaching, to trifurcate. An obvious example is that kind of standard of decision known as the standard of proof: what in theory might have been a continuum of standards divides in practice into the three distinct standards of preponderance of the evidence, clear and convincing evidence, and proof beyond a reasonable doubt. Other examples suggest both that I am not imagining the prominence of three and that more than coincidence is at work. Part I of this essay describes the role of the number three in procedure, with particular regard to standards of decision. Part II reviews the contribution of cognitive psychology toward understanding certain relevant limitations on human capabilities. Part III argues that although the number three represents more than imagination or coincidence for the proceduralist, its persistent recurrence need not lead to Pythagorean conclusions of magic. Instead, limits on our cognitive powers likely dictate this systematic structure of procedure, awareness of those limits should help us better to understand and shape that procedure, and these insights can lead to very specific suggestions for reform.