Substantive Truth in Criminal Adjudication The Necessity of Implementing the Adversarial Procedure

This article reinterprets the concept of substantive truth in criminal adjudication and examines the institutional conditions necessary for realizing fair justice. It argues that fairness in criminal proceedings rests on two interrelated dimensions. The first is epistemic: the attainment of accurate knowledge of the facts through procedures that respect and protect fundamental rights. Substantive truth, in this sense, refers to reaching reliable knowledge of the objective reality of the case. The second is normative: the imposition of criminal sanctions through conscientious moral reasoning and the correct application of law. Judicial fairness is secured only when both accurate fact-finding and normatively justified decision-making are achieved. The article further contends that truth-seeking in criminal procedure is not unlimited but arises only where grounds for criminal liability exist and must operate within established procedural and evidentiary rules. Although these rules are designed to facilitate truth-finding, they may also generate tensions and practical constraints, as reflected in legislative frameworks and judicial practice in Mongolia and other jurisdictions. Prioritizing fundamental values―human rights, morality, and ethical standards―over unrestricted truth-seeking does not undermine justice; rather, it reinforces its legitimacy. To address structural tensions between truth and procedural safeguards, the article advocates strengthening the adversarial framework of criminal proceedings. Comparative developments, including reforms in the Republic of Korea and Japan influenced by the American model, illustrate that transitions toward adversarial mechanisms are effective only when harmonized with domestic legal traditions and cultural contexts. Finally, drawing on Karl Popper’s falsification principle and Paul Feyerabend’s theory of proliferation, the article argues that structured contestation between competing arguments provides a rational and democratic method for constructing substantive judicial truth.