國民參與刑事審判程序的證據能力判斷：兼論鑑定證據之證據能力判斷標準

Admissibility of Evidence in the Lay Participation System of Criminal Courts: With an Attention to Scientific Evidence

刑事訴訟法並未規定「證據能力」概念之一般性要件，歷來法院實務因此甚少審酌，以致未能落實此一概念過濾證據資料的功能。惟因刑事訴訟法採取卷證併送、容許法院不先行判斷證據能力、信賴職業法官心證不受影響等制度，掩蓋了證據能力概念未能落實的問題。然而依據「國民法官法」，法院必須在準備程序中裁定證據資料有無證據能力。若仍依循既有實務的操作，讓大量的證據資料湧向國民法官法庭，將顯出審理爭點混淆、難以形成心證、審判冗長遲滯等嚴重後果，導致國民參審制度的崩潰。而在各種證據類型中，又以涉及法律以外專業知識的鑑定證據，法院最難判斷證據能力。本文結合我國憲法解釋和美國法制，探索「自然關聯性」作為證據能力要件之內涵，並釐清亦有篩選證據功能的調查必要性概念，提出明確的操作標準。就鑑定證據之證據能力，本文考察美國法制的「弗萊法則」與「道伯法則」指出：弗萊法則追求的價值，正與我國司法改革和國民參審制度之目標──增進判決一致性、正確性、避免審判冗長──相適合；道伯法則雖有其優點，但運作所必要的配套措施在我國卻不存在。因此本文主張我國可參考弗萊法則的「普遍接受」標準，建立科學證據之證據能力判準。

"This article discusses admissibility of evidence in Taiwan’s lay participation system of criminal trials, which will be implemented in 2023. Admissibility means that proffered evidence may be submitted to finders of fact and be evaluated for its probative value. Professional judges serve as a filter to screen out unqualified evidential materials. According to Taiwan’s Constitutional Court decision, the necessary element for admissibility in criminal trial is“natural relevancy”. Since this concept does not appear in statutes, nor does the Court provide its definition,“natural relevancy”is open to interpretation. So, the filter mechanism for admissibility does not function effectively and consistently in existing trials. Nevertheless, it does not seem to be a serious problem, because current criminal trials are dominated by professional judges, who take charge of everything: admissibility, probative value of evidence, and final decisions of cases. Nevertheless, the lack of a filter for unqualified evidence will be a nightmare in the lay participation system. Inadmissible evidence is not allowed to be submitted to lay judges, in case it will bias their decisions, and substantially delay the trial. Hence, professional judges will be expected to insulate lay judges from inadmissible evidence, by excluding evidence in the preliminary hearing stage. However, professional judges do not have a useful tool for excluding inadmissible evidence, because there has been no clear definition of admissibility and little discussion about this issue.After reviewing academic literature and court decisions in Taiwan and the United States, this article holds that natural relevancy should be interpreted as the minimum probative value that an evidential material has on the fact which is of consequence for determination of a case. This is the standard adopted in the Federal Rules of Evidence of the U.S., and I argue for its adoption in Taiwan as well. In addition to the general definition of natural relevancy and admissibility, this article particularly focuses on how these concepts should apply to scientific evidence. Neither legal knowledge, common sense nor experience can help professional judges decide whether scientific evidence is scientifically proved, and should be factored into court decisions. That is, some additional criteria have to be defined for the evaluation of scientific evidence, to help professional judges fulfill their tasks. This article contends that the debate concerning the“Frye test”and the“Daubert test”, in the U.S., may provide a useful reference for Taiwan’s courts."