A group of the scholars of legal theory declared: “The term ‘analogy’ (qiyās) is used in its literal sense for analogical reasoning by representation (qiyās al-tamthīl) and only figuratively for analogical reasoning by subsumption (qiyās al-shumūl).” This was the view of Abū Ḥāmid al-Ghazālī, Abū Muḥammad al-Maqdisī, and others.

Another group held precisely the opposite, maintaining that the word is literal in subsumption and figurative in representation; Ibn Ḥazm and those who follow him espoused this opinion.

The overwhelming majority of scholars, however, state that the term is literal in both cases and that rational analogy embraces them alike. This is the position adopted by most writers on the principles of religion, the principles of jurisprudence, and the various rational sciences, and it is the correct view. It is likewise the stance of the majority among the followers of the four Imams and others—such as Shaykh Abū Ḥāmid, Qāḍī Abū Ṭayyib and their peers, as well as Qāḍī Abū Yaʿlā, Qāḍī Yaʿqūb, al-Ḥulwānī, Abū al-Khaṭṭāb, Ibn ʿAqīl, Ibn al-Zāghūnī, and many more—for the essence of one type of analogy is identical to that of the other; only the outward form of the inference differs.

In Arabic usage, qiyās means “to measure one thing by another.” This includes measuring a given particular against another particular that resembles it, and measuring it against a universal that encompasses it together with its counterparts, for a universal is a mental exemplar of its particulars and therefore accords with them.

The essence of analogical subsumption
Analogical subsumption is the mind’s passage from a specific, concrete case to an encompassing, shared universal that includes it and others, and then judging the particular by what necessarily follows from that universal—moving from the universal that entails to the first entailed, namely, the particular itself. Thus the reasoning travels from the specific to the general and back again: from the particular to the universal, and from that universal to the original particular, upon which the ruling is pronounced by virtue of the universal.

For this reason the proof is narrower than what it indicates, namely the ruling; the ruling follows necessarily from the existence of the proof, and what is necessitated cannot be more specific than that which necessitates it.