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.