Qiyas in the Thought of Imam al-Ghazali and Its Impact on the Development of His Usul al-Fiqh Methodology: An Analytical Study Based on Al-Mustasfa and Shifa' al-Ghalil

Abstract

This study examines analogical reasoning (qiyās) in the thought of Imam al-Ghazālī and its role in shaping his legal-theoretical methodology, through an analytical study of his discussions in al-Mustaṣfā min ʿIlm al-Uṣūl and Shifāʾ al-Ghalīl. It aims to explore al-Ghazālī’s conception of qiyās, both linguistically and technically, identify the distinctive features of its various types, determine the conditions governing its validity, examine the methods by which the effective cause (ʿillah) is established, and clarify its role in ijtihād and the derivation of legal rulings. The study adopts a descriptive-analytical approach, supplemented by a comparative method where a comparison between al-Ghazālī’s views and those of other legal theorists is required. The study concludes that al-Ghazālī did not regard qiyās merely as a means of extending a ruling from an original case to a subsidiary case; rather, he viewed it as an integrated method of legal reasoning based on identifying the effective causes underlying legal rulings and relating them to the objectives of Islamic law (maqāṣid al-sharīʿah), while adhering to methodological constraints that prevent uncontrolled expansion in causal reasoning. The study further demonstrates that al-Ghazālī distinguished between qiyās al-dalālah (analogical reasoning by indication), qiyās al-ʿillah (causal analogy), and qiyās al-shabah (analogy based on resemblance), assigning them different degrees of evidentiary strength according to the degree of certainty and clarity with which the effective cause is established. This distinction contributed to an uṣūlī methodology that combines the precision of rational inquiry with adherence to the revealed legal text.