证明力规则的形成、功能及面临的深层挑战

Rules of Weight:Its Evolution,Function and Deeper Challenge

现代证据法的一个核心假设是,它的规则仅有可采性规则。也就是说,它们告诉法官是否可让案件事实认定者接触某一特定的证据,但它们并不打算告诉案件事实认定者如何去评价具备可采性的证据。然而,我们可以假设有这样一种规则制度,可以通过指示适用法律来帮助案件事实认定者衡量证据价值,例如,法律认为一类证据(如传闻证据)的“证据价值不高”。事实上,这种证据的证明力规则是一种源于罗马法的古老观念。但它们长期以来一直被研究证据的学者所忽视,或者在考虑时被认为是过时的,并与陪审团审判制度极不融洽。本文认为,这种对证明力规则的敌意是不合理的,应认真对待证明力规则并将其作为证据改革的可能方向。鉴于陪审团审判的案件数量现在越来越少,并且在使用陪审团时其裁量权已受到多方面的限制,因此针对证明力规则的正统观念现在看来已经过时了。另外,有理由认为这些规则可能有助于利用法庭科学来查明案件事实。法院过去对证明力规则的运用,当前其在行政裁决中发挥的作用,以及最近认知心理学方面的研究都表明证明力规则可以促使更公平、更有效且最重要的是更准确地查明案件事实。这些优点使联邦最高法院近期对行政裁决使用证明力规则的谴责更加难以得到认可。

A central assumption of modern evidence law is that its rules are rules of admissibility only.That is,they tell judges whether or not a given piece of evidence may be viewed by the factfinder,but they do not purport to tell the finder of fact how to evaluate the evidence once admitted.One can imagine,however,a system of rules that helps factfinders weigh evidence by instructing them,for instance,that the law considers a class of evidence(say,hearsay) to be of “low weight.” In fact,such rules—rules of weight—are an old idea with roots in Roman law.But they have long been ignored by evidence scholars or,when considered,judged to be anachronistic and deeply inconsistent with a system of trial by jury.This article argues that such hostility to rules of weight is unjustified and that their use should be taken seriously as a possible direction for evidence reform.Given that jury trials are now increasingly rare and that,when a jury is used,its discretion is already constrained in a number of ways,the orthodox view of rules of weight now itself seems outdated.Furthermore,there are reasons to think that such rules could be beneficial for forensic factfinding.The past use of them by courts,their current role in administrative adjudication,and recent research in cognitive psychology all suggest ways in which rules of weight could make factfinding fairer,more efficient,and,most important,more accurate.Such benefits make the Supreme Court’s recent condemnation of the use of rules of weight in the administrative context that much more difficult to justify.