And this principle is one of the innovated principles (1) in Islam. None of the early generations of the ummah, nor its leading imams, ever said that the intellect cannot deem an act good or evil, or that the goodness or badness of an act cannot be known through reason. The very controversy about this point [first emerged in the third century AH, and the dispute has persisted ever since] (2) among the jurists of the ummah as well as its scholars of hadith and kalam (3). There is hardly a single faction that is not internally divided over it, and it is likely that the majority of the community dissents on the matter. Elsewhere we have written a decisive treatment of this issue (4), clarifying the portion of truth that each side possesses.
It may further be said: Even if this question were absolutely sound, neither you (5) nor your associates possess any conclusive proof that would exclude the opposing view; your only reliance (6) and the reliance
(1) The original read uṣūl (foundations). It is supported by manuscripts S and T and may suit the context best.
(2) The text enclosed in braces is omitted in manuscript S.
(3) The issue of taḥsīn al-ʿaql wa taqbīḥuh (the rational valuation of good and evil) has been widely debated. The Mu‘tazilites and those among the followers of Abū Hanīfa, Mālik, al-Shāfi‘ī, Aḥmad and Ahl al-Ḥadīth, etc., affirm that reason can judge good and evil. The Ash‘arites and those among Mālik’s adherents, al-Thumfī, Aḥmad and others deny this. Both parties agree that beauty and ugliness—understood as an act’s being beneficial and fitting for the agent or harmful and repugnant to him—can be known by reason just as by revelation. See Ibn Taymiyya, Majmū‘ Fatāwā, vol. 8, p. 90; al-Shahrastānī, Nihāyat al-Iqdām, pp. 370–396.
(4) See the chapter on this dispute in Ibn Taymiyya, Majmū‘ Fatāwā, vol. 8, pp. 428–436.
(5) The word laka is omitted in manuscript S.
(6) See what al-Juwaynī relies on in al-Irshād, pp. 258–267: that reason does not determine an act’s moral good or evil in legal rulings, but instead acquires these valuations from the sharia’s sources, binding the believer through scriptural hearing.