At-Tawḥīdī’s 17th Night : Refutation of a Threatening Heresy, i.e. the Epistles of the Brethren in Purity. The 17th night of the Kitāb al-imtāʿ wa-l-muʾānasa written by Abū Ḥayyān at-Tawḥīdī can no longer be considered as a testimony on the authorship of the Rasāʾil Ikhwān aṣ-ṣafā, for the very epistles were already written around 307/920. Indeed, they were well-known in Andalusia in the West around the middle of the century, and among the Ismāʿīlīs in the East already at its beginning. Furthermore, we can demonstrate that their doctrine would be anachronistic out of the late third/ninth century. Then, the 17th night must be reinterpreted as the rebuttal of the Brethren in Purity’s views in a very structured manner employing different characters : the minister Ibn Saʿdān, al-Bukhārī, Zayd b. al-Rifāʿa, al-Maqdīsī, an-Nīsābūrī and al-Balkhī, in order to represent the different degrees of initiation and symbolize progression of the heresy.

Before Ṯābit b. Qurra's translation, there was a first Arabic version of Nicomachus’ Introduction to arithmetic. Full of mistakes, it was revised by an anonymous student of al-Kindī. Thanks to the part that Freudenthal and Levy have edited and translated, we are now able to identify this reviser as Aḥmad b. al-Ṭayyib al-Saraḫsī, who we also identified as the author of the Rasā᾿il Iḫwān al-Ṣafā᾿. The comparison of the gloss written by this reviser with a new fragment of Saraḫsī on one part, and with the “ Epistles of the Brethren in Purity ” on the other, corroborate Saraḫsī’s authorship of the epistles. Furthermore, studying the misunderstandings on Nicomachus’ text in this kindianised version gives a new light on al-Kindī’s attempt to unify philosophy and on the specific ontology of the Brethren in Purity.

So far thirty of the fifty-two Epistles of the Brethren in Purity (Rasāʾil Iḫwān al-Ṣafāʾ) have been edited by the Institute of Ismaili Studies. The time has come to review the project itself and ask what has already changed in the new Epistles. Unfortunately, the ambitious project of a critical edition gave birth to an inconsistent patchwork of individual editions and translations which impairs the understanding of the Rasāʾil. The precise analysis of details from both the Beirut and London editions is also the occasion to test the two theories of the Epistles: the main stream view of a syncretic doctrine resulting from a stratified redaction, and our hypothesis of a highly philosophical work written by Aḥmad b. al-Ṭayyib al-Saraḫsī.

Les Épîtres des Frères en Pureté forment une encyclopédie des sciences philosophiques (au sens hégélien du terme) composée par Aḥmad b. aṭ-Ṭayyib as-Saraḫsī vers 280/894 à partir des travaux effectués par les Frères en Pureté, héritage social du « cercle d’al-Kindī ». Le système trouve ses fondations dans l’arithmétique de Nicomaque de Gérase, est composé de la science kindienne, et s’élève sur les préoccupations politiques d’al-Ǧāḥiẓ, il n'en réalise pas moins une construction philosophique originale.
Historiquement, une fois qu'on a démontré l’unicité du rédacteur, établi qu’Abū Ḥātim puise sa réfutation d’Abū Bakr ar-Rāzī dans la doctrine rasaélienne de l’héritage scientifique des prophètes, compris que les Rasāʾil sont entièrement alimentées par le kindisme, repéré que le seul héritier d’al-Kindī apte à une telle entreprise est Aḥmad b. aṭ-Ṭayyib as-Saraḫsī, la comparaison des fragments saraḫsiens avec les épîtres révèle l’identité de style et l'existence d'éléments doctrinaux propres à ces deux seules œuvres. L’identification de surcroît d’as-Saraḫsī au réviseur de l’Introduction arithmétique de Nicomaque autorise à postuler un système philosophique fondé mathématiquement.
Préoccupées par le problème ontologique de la diversité du réel sous l’unité du Créateur, par le problème épistémologique de la divergence des méthodes et des doctrines scientifiques et religieuses malgré l’unité de la vérité et par le problème politique de la discorde entre les hommes malgré l’interdépendance de tous, les Rasāʾil Iḫwān aṣ-Ṣafā entreprennent d’unifier la multiplicité empirique des êtres, de coordonner les disciplines du savoir et de réconcilier les hommes en une communauté vertueuse au moyen de trois concepts mathématiques : par leur origine dans l’émanation des êtres à partir du Créateur exprimée au moyen de la suite arithmétique, dans leur structure par la compréhension des analogies et des puissances entre les choses que révèle le rapport harmonique, et dans leur finalité au moyen de l’abstraction géométrique des formes hors de la matière qui est constituée en modèle initiatique des âmes à la séparation d’avec le corps.

The Rasāʾil Iḫwān al-Ṣafā build a thinking on salvation preoccupied by ideological pluralism. So huge is the temptation to locate them on the map of theology of religions. But, it appears to resist to such a location. Does it indicate an inconsistent view or reveal the narrow-mindedness of our views on salvation?
To answer this question, we began by formulating the aporetic structure underlying discussions in theology of religion. Like this, we cleared three inconsistent postulates on soteriology:
1. God want salvation for all the people; 2. He indicated a path of salvation; 3. who doesn’t follow this very path cannot find salvation.
Applying this structure to Islamic context, we identified Islamic forms of exclusivism (denial of 1), pluralism (denial of 2), inclusivism (denial of 3). But the Epistles of the Brethren in Purity still slip out from our grasp and, surprisingly, they’re the only ones to reconciliate the three postulates. How can we maintain that God wants salvation for all the people if He gives it only to those who followed His path? By understanding that this path includes the human paths as parts of it. We call it the soteriological complementarism of the Brethren in Purity.
How theology of religions missed such a solution of the problem of salvation and pluralism? By its common agreement on the hidden postulate that: 4. God agrees to save only a few. The Epistles of the Brethren in Purity take the opposing view: no one will find salvation without all the others. Then salvation’s nature is revisited.

The ḥadīṯ transmitted by Abū al-Dardāʾ (d. 31/652) on the scholars, heirs of the prophets, has been quoted to back different philosophical, religious, educational or political assertions. However, its syntactic analysis shows great inconstancies that make sense if one considers its splitting by the traditionist Ibn Raǧab al-Ḥanbalī (d. 795/1393) which reveals that this ḥadīṯ is in fact a patchwork of shorter ḥadīṯs. Only the main assertion of this ḥadīṯ remains without source in the ḥadīṯ corpus. Its genealogy must be found in another framework, namely, the philosophy of the 3rd/9th century, and especially the Epistles of the Brethren in Purity which clarify its meaning: this ḥadīṯ is not first and foremost a praise of science, nor a justification of prophecy, but a religious legitimation of philosophy and a way to solve the epistemological problem of the foundation of knowledge.