This chapter explores the seminal contribution to Islamic legal theory of al-Ghazālī (d. 505/1111), focusing on his defence of legal analogy (qiyās) against its detractors in al-Mustaṣfā min ʿIlm al-Uṣūl. Al-Ghazālī discusses the justifications for analogy and bases its authority on revelation, rather than reason alone. He opposes both those who deem it rationally impossible to employ analogy in legal matters (against the Baghdādī Muʿtazila and the Shīʿa) and also those who deem it rationally necessary (such as the Baṣran Muʿtazilīs). His position is thus typically an Ashʿarī one: by showing that it is neither impossible nor necessary to use analogy, reason concludes that it is possible to use analogy. This discussion of a point of legal theory is thus heavily inflected by theological debates.

This chapter presents the discussion of whether every mujtahid is correct (hal kull mujtahid muṣīb?) as found in al-Qawānīn al-Muḥkama fī l-Uṣūl of Abū al-Qāsim b. Muḥammad al-Ḥasan al-Shaftī al-Qummī (d. 1231/1816). In particular, it explores the implications of this largely legal question for theology and otherworldly salvation (i.e. soteriology). Taṣwīb theories of ijtihād (sometimes called ‘infallibilist’ theories) commonly held that in the absence of definitive evidence all suitably determined opinions are correct. Takhṭiʾa (‘fallibilist’ theories) held that the correct position was only ever one, and ijtihād was a fallible attempt to discover this one correct position. Ultimately both positions allowed for some legitimate diversity in scholarly opinion on matters of law. The implications of this legal epistemology informed Muslim ideas about the implications of holding incorrect theological beliefs.

What do purist Salafis mean when they say everyone must follow the Qur'ān and Sunna? What level of knowledge must one have in order to do this? In the case of laypeople, are they to follow scripture directly or do they perform taqlīd? In this chapter, I answer these questions in order to shed light on the rhetorical strategies used by Salafis and Traditionalists. Salafis critiques of Traditionalism have brought forward a cluster of issues in which the texts seem to go against the position of the madhhabs. The legal theory of the madhhabs is often inaccessible to lay Muslims and is based on the global demands the positions of Traditionalists scholars have taken on various issues. On the other hand, independent Salafi thinkers like Albānī bring forward simple and easy-to-understand texts. This chapter focuses on how purist Salafis critiqued the madhhabs by portraying Traditionalists as ones that follow scholars instead of the authentic teachings of the Qur'ān and Sunna. I explain how the variant definitions Salafis and Traditionalists have of taqlīd and ijtihād often leads to confusion on their practical application of Islamic law and religious authority.