Islamic principle using reasoning/analogy is called:

Qiyas refers to the Islamic principle using reasoning or analogy to derive legal rulings when direct texts from the Quran or Hadith are not available. It plays a crucial role in Islamic jurisprudence, allowing scholars to extend the principles found in traditional sources to new situations that arise in society. By drawing analogies between established rulings and new cases, Qiyas helps ensure that Islamic law remains relevant and applicable in various contexts, addressing contemporary issues while remaining rooted in the foundational texts.

The process of Qiyas involves identifying a common underlying reason ('illa') that justifies a legal ruling in the original case and applying that reasoning to the new situation. For instance, if a ruling on the prohibition of intoxicants is established through explicit texts, scholars may use Qiyas to argue against the permissibility of substances that share similar harmful effects, even if those substances are not explicitly mentioned in the scriptures. This method thus provides a flexible yet structured approach to Islamic law, allowing for adaptation without compromising its core principles.

In contrast, other terms like Ijma (consensus of scholars), Ijtihad (independent reasoning), and Sunnah (practices of the Prophet Muhammad) serve different purposes within Islamic jurisprudence. While Ijma emphasizes collective agreement among scholars and Ijtihad focuses on personal reasoning in deriving rulings, Qiyas specifically utilizes analogy to bridge the gap between established law and new circumstances. Understanding Qiyas is essential for students of Islamic jurisprudence, as it reflects the dynamism of Islamic legal thought and its capacity to address evolving societal needs.