The Roman Maxim “ei incumbit probatio qui dicit, non qui negat” in Civil Law and Common Law – A Comparative Study

Abstract

The aim of this article is to analyse the significance and scope of application of the Roman legal maxim ei incumbit probatio qui dicit, non qui negat in contemporary legal systems, namely civil law and common law, with particular emphasis on Polish and English law. The starting point of the analysis is the presentation of the origins and functions of legal principles in Roman law, followed by their evolution towards the modern understanding of legal principles as norms of significant axiological and functional importance within the structure of the legal system. The analysis focuses primarily on a comparative assessment of the interpretation and implementation of the principle in Polish civil procedure and in the English procedural model based on the Civil Procedure Rules. Particular attention is devoted to the distinction between the legal (material) and evidential (formal) burden of proof, as well as to the practical mechanisms of its application in judicial proceedings, and to the role of expert evidence as one of the fundamental instruments for discharging the burden of proof in cases requiring specialised knowledge. The author argues that, despite the universal character of the Roman principle of the burden of proof, its contemporary operation is shaped by differing institutional solutions characteristic of civil law and common law systems, particularly with regard to the appointment of experts and the form of expert opinions.