Expert Evidence, Probability and Judicial Certainty in Criminal Proceedings

Abstract

This article examines the role of expert evidence within the system of proof in criminal proceedings, focusing on the relationship between probabilistic expert opinions and judicial certainty. Particular attention is paid to the judge’s internal conviction (intimate conviction) as a decisive element of fact-finding and sentencing. The article argues that the assessment of evidence is inherently probabilistic, even where this is not explicitly acknowledged in judicial reasoning, which is especially evident in the case of expert opinions that rarely provide categorical conclusions. The resulting tension between probabilistic expert findings and the legal requirement of certainty raises fundamental questions regarding the evaluation and reliability of expert evidence. Using a theoretical and comparative approach, the study explores the limits of judicial certainty, the evidentiary value of expert opinions and their potential role as new evidence (novum) in retrial proceedings. It proposes a system-based perspective on criminal proof, according to which expert evidence and judicial conviction should be assessed as interconnected elements of the criminal justice system.