This article presents a comprehensive study of one of the most contentious and methodologically complex categories in criminal procedure law-the concept of «conscience» as employed by the legislator in Part 1 of Article 17 of the Criminal Procedure Code of the Russian Federation to characterize the basis for the evaluation of evidence. The aim of the work is to theoretically overcome the doctrinal ambiguity and practical vagueness of this concept by developing its legal, functional-legal definition, which integrates insights from the philosophy of law, ethics, and procedural science. The author proposes an original concept that interprets «conscience» as a specific procedural-legal model for decision-making, synthesizing legal consciousness, professional experience, rational analysis, and moral responsibility. On this basis, the fundamental untenability and inadmissibility of replacing a judge or prosecutor with artificial intelligence, which lacks these qualities and, consequently, «conscience» as a legal category, are argued. As a key legislative conclusion, the author develops and substantiates a proposal to supplement Article 5 of the Criminal Procedure Code of the Russian Federation with a legal definition of «conscience», designed to operationalize this concept and reinforce the anthropocentric foundation of criminal justice.