The Oath in Islamic Criminal Procedure: Evidence Theory and a Comparative Analysis with Modern Criminal Procedure

Abstract

This study examines the conceptual framework of oath (yemîn) in Islamic procedural law, its place within the theory of evidence, and its position in comparison with modern criminal procedure. An oath—affirmed by invoking the Divine Name—serves to strengthen a statement and, under specific conditions, functions as a means of proof. Ḥanafī jurists generally treat the oath as a defensive device and a negative presumption, directing it only to the defendant; Shāfiʿī jurists, by contrast, recognize both evidentiary and defensive functions and allow it to be tendered to the plaintiff as well. The oath is not admissible in ḥadd cases or (apart from qasāmah) qiṣāṣ cases where God’s right predominates; it does, however, operate as a complementary proof in property disputes and in offenses converted into monetary liability (e.g., diyah, arsh, compensation). Procedural validity depends on conditions such as a properly filed claim, the defendant’s denial, the plaintiff’s failure to adduce evidence, and the oath’s personal performance before the judge. Refusal of the oath (nukūl) is often treated as an implied confession with adverse consequences; within the Ḥanafī school, its penal effects are debated between Abū Ḥanīfa and Abū Yūsuf–Muḥammad. In modern criminal procedure, prosecution lies with the state; oaths are merely conscientious undertakings imposed on witnesses and experts and are not evidence. Given scientific-evidentiary standards and objectivity, the oath’s probative force has effectively lapsed, and monetary penalties like diyah/arsh have no analogue under the Turkish Penal Code.