The factors favouring this conspicuous rise of the Ismailis were no doubt manifold. The progressive dismemberment of the ‘Abbasid empire and the political disarray of the ‘Abbasid Caliphate itself were moving towards a climax. The political upheavals, internal wars, devastation and economic dislocation caused widespread discontent and unrest, and Ismailis have sometimes been interpreted as essentially a social revolutionary movement arousing the oppressed to revolt against the established powers and institutions. Specific local conditions evidently in some instances lent the Ismailis such a character. But the appeal of its message to so many others who did not belong to the oppressed and would not benefit from their revolt must warn against any generalisation of this interpretation. The decline of authority and respect which the ‘Abbasid Caliphs, the representative heads of Sunni Islam, could command, naturally strengthened the hand of the traditional opposition, particularly the Shi‘a. The other major branches of the Shi‘a, the Imamiyya and the Zaydiyya, who had been well established for over a century before the Ismailiyya, indeed also benefited to some extent from the situation to consolidate their position. Yet their gains were modest in comparison with the almost meteoric rise of the fortunes of the Ismailiyya, who for some time seemed close to overthrowing the ‘Abbasid Caliphate and restoring the universal empire of Islam on its own terms.
The superior centrally directed organisation of the secret Ismaili missionary activity evidently furthered its quick expansion throughout the Islamic world. But the devotion and success of the Ismaili missionaries must have been due in large part to the intrinsic appeal of the message itself. Ismaili teaching from its beginnings offered a comprehensive and coherent view of God, the universe and the meaning of history. While its core embodied general Islamic and Shi‘i tenets and ideals, it integrated some of the Hellenistic spiritual and intellectual heritage, which, though mostly condemned or shunned by more conservative Sunni scholars, had indubitably become part of Islamic civilisation. The anti-Ismaili polemicists might well accuse Ismaili missionaries of trying to insinuate themselves amongst people of the most varied backgrounds by deceptively catering to their particular beliefs and sentiments. In fact, however, Ismaili doctrine did not borrow indiscriminately but rather selected what it found congenial to its basic convictions and amalgamated it into a coherent synthesis of its own.
The Ismaili view of prophecy and the Imamate was based on belief in the permanent need of mankind for a divinely guided, impeccable leader and teacher to govern it justly and to direct it soundly in religion. In the absence of a prophet, this was the function of the Imam. The Imamate thus was part of the prophetic chain which spans the history of man from the beginning to the end. This belief about the significance of the Imamate was part of the heritage which the Ismailis carried on from the earlier Shi‘a, but transformed it into its own cyclical but ultimately teleological view of history. The religious evolution of man according to this view is consummated in seven eras, each one inaugurated by a Messenger Prophet or Enunciator (Natiq). In the first six eras, the Messenger Prophets, Adam, Noah, Abraham, Moses, Jesus, and Muhammad, each brought and proclaimed a revealed message, a scripture containing in its apparent and exoteric (Zahir) aspect, a religious law. Each one was succeeded by his Legatee (wasi), or Silent One (samit), whose task it was to reveal the inner, esoteric (batin) truths which lay concealed in the Scripture and the Law to the few who were capable and deserving of receiving them.
These esoteric truths were, in contrast to the changeable nature of the Law, eternal and unchanging throughout all eras. The Legatee in turn was followed by seven Imams who guarded the true meaning of the Scripture in both its exoteric and esoteric aspects. The seventh Imam in each era then rose in rank to become the Messenger Prophet of the next era and revealed a new scripture abrogating the previous one. This pattern would change only in the seventh, final era. Its Messenger Prophet, the Expected Qa’im or Mahdi, was not to reveal a new religious law but to make public fully and without restriction the esoteric truths which had so far been revealed only imperfectly, upon initiation and under the seal of secrecy, to the few truly faithful followers of the Imams. He would thus inaugurate before the end of the world an era of pure spiritual knowledge unshackled by the Law.
The esoteric truths (haqa’iq) which the divinely guided members of the prophetic chain dispensed were essentially gnostic. They were based on revelation and transcended human reason, though they gave the rational soul its perfection and thus led man to his ‘second creation’ (khalq thani). The human intellect could not reach them by its own independent efforts. Only by initially turning to the guidance of the Prophets and the Imams could man partake of the divine support (ta’yid) through which their teaching would become a salvatory revelation.
In concord with the prophetic nature of all religious knowledge, Ismaili theology was revelational, rather than rational, in its very core. Classical Ismaili doctrine conceived of God and the principles of the spiritual and physical worlds in Neoplatonic terms. God was the unknowable absolute One who could not be comprehended or described by reason. He transcended the Universal Intellect, the first principle of the spiritual world of which He was the source, without being Himself Intellect as the Aristotelian tradition maintained. Following the via negationis, Ismaili doctrine removed all attributes and names from God and described Him as transcending being and non-being. While the Ismailis adopted these concepts from Neoplatonic tradition, they also introduced certain characteristic changes in the Neoplatonic cosmology giving it a more Islamic character. Thus it described the Universal Intellect not as proceeding from the One by emanation but as brought forth through His divine Order (amr) or Word (kalima) in the act of primordial, extra-temporal Origination (ibda‘).
The Order was, however, addressed to the whole universe, and the Intellect contained the forms of all things in the spiritual and physical worlds which were, thus, originated all at once (daf‘atan wahidatan) in the ibda‘. They were all directly related to God in their origination, though they were manifested only gradually in the process of emanation and causation proceeding from the Intellect in accordance with the divine ordination (taqdir). The Intellect was called the First Originated Being (al-mubda‘ al-awwal), since the Order, though logically prior to it, became united with it in existence. God, by His primordial act could be called the Originator (al-mubdi‘).
The Qur’anic origin of the term ibda‘
God is described in the Holy Qur’an (ii,117 and vi, 101) as badi‘ al-samawati wa’l-ard and of the divine amr, which was, moreover, identified with the creative imperative kun, ‘is evident’. At the terminological level, this Islamisation was carried further by the equation of the Universal Intellect with the Qur’anic Pen (qalam), Throne (‘arsh) and the Decree (qada’) and similar equations in respect to the other principles of the spiritual world. More significantly, however, these changes reflected the volitional nature, the liberty of the act of creation as conceived in the Holy Qur’an and Islamic tradition in contrast to the emanational doctrine of the philosophers. With the same motive, Ismaili theology expressly denied, against the philosophic tradition, that God is the first cause (‘illa). The first cause of the world was rather His Order or Word which became united with the Universal Intellect. God could only be called causator causae causarum (mu‘ill ‘illat al-‘ilal).
The attractiveness of Neoplatonic theology to Ismaili thought was in part no doubt due to its rigorous affirmation of the unity, the perfect oneness, of God and His absolute transcendence. Affirmation of the unity of God (tawid) and of His transcendence and otherness in relation to all created being (tanzih) were indeed fundamental principles of Islam and, in one way or another, present in all Islamic theology. Neoplatonism and Ismaili teachings carried these principles to their ultimate limit. Abu Ya‘qub al-Sijistani, the earliest of the Neoplatonic Ismaili authors whose theological works have largely been preserved, discussed the views of various Muslim theological schools on God’s transcendence.2 He rejected even the most radically anti-anthropomorphist doctrine of the rationalist Mu‘tazila who were commonly accused of going too far in their negation and metaphorical interpretation of the divine attributes and thus of committing ta‘til, denudation of the Divine Essence. Yet Abu Ya‘qub viewed their ta‘til as merely a hidden form of tashbih, ascription of similarity with the creation to God, since the mere repudiation of all similarity with the physical nature of man assimilated Him to the spiritual beings. The negation of any similarity of God with creature must thus be complemented with a negation of this negation which in effect removes from Him any similarity with the intelligible beings of the spiritual world. In this paradoxical double negation, Abu Ya‘qub reaffirmed the suprarational nature of Ismaili theology. It was in this transcendence vis-á-vis reason itself, in the necessarily revelational basis of the Neoplatonic concept of the One, that the Ismaili writers recognised its essential affinity to their own point of view. Characteristically, Ismaili theology did not attempt to offer a proof of God, that first concern of any rational theology. A rational proof of what is beyond reason and being was evidently futile. Nor was there any need for it, for God, Abu Ya‘qab affirmed, is more certain than everything certain (athbatu min kulli thabit). This was a certainty which becomes evident to the human mind only by revelation.
Rational theology had in the early centuries of Islam been represented most consistently and conspicuously by the school of the Mu‘tazila. During the first decades of the fifth century AH / eleventh century CE, it was systematically reformulated on the basis of a different tradition, by the philosopher who was to influence Eastern Islamic thought, including scholastic theology, most profoundly for many centuries to come: Ibn Sina (d. 428 AH /1027 CE). Ibn Sina himself related how his father had been converted to Ismailis teachings and how he used to hear his father and his brother discuss philosophical and scientific questions according to the Ismailis’ views. They invited him to join their discussions but he felt unable to accept their views. He thus must have been thoroughly acquainted with Ismaili thought but he turned away from it to the more pure Peripatetic tradition represented in Islam prior to him especially by al-Farabi. Aristotle and al-Farabi were indeed his chief teachers. Though he held the Theology ascribed to Aristotle (which actually consisted of extracts from the Enneads of Plotinus) to be authentic, he did not follow it in those aspects which the Ismailis found most congenial to their thought.
God in Ibn Sina’s theology does not transcend being. Ibn Sina described Him as the Necessary Being (wajib al-wujud). This concept was indeed the basis of his proof of the existence of God which argued from the essential contingency of the world for the need of an ultimate, necessary cause. Nor did God in Ibn Sina’s view transcend reason. He described Him as in essence an intellect , intellecting and intelligible (‘aql, ‘aaqil, ma‘qul). God was in this respect similar to the principles of the spiritual world which Ibn Sina also defined as pure intellects. In agreement with the philosophical tradition, he described God as the First Cause. Affirming the thesis that one can proceed only from One, he held that God brought forth the First Intellect by necessity, not by act of volition.
Viewing God as in principle intelligible, Ibn Sina discoursed freely on His nature, His attributes, and on the spiritual world in purely rational terms, without recourse to scriptural arguments or religious symbolism. His theology resembled in this respect that of the Mu‘tazila, despite the many points of conflict between him and them; and al-Ghazali, in his criticism of Ibn Sina’s philosophy, could maintain that his view of the divine attributes basically agreed with the Mu‘tazili ta‘til. Reason, in his view, has indeed no need of prophetic guidance in attaining knowledge about the divine. There was, to be sure, a place for prophethood and for mysticism in Ibn Sina’s philosophy and his belief in Islam was certainly sincere. But prophecy belonged to the same realm as reason. The knowledge of the prophets came from the same source as for every human mind, the Tenth, or Active Intellect, who was the Giver of Forms (wahibal-suwar); though their contact with it was more intimate and thus their knowledge more immediate and universal. They were able to translate this knowledge into images and symbols which appealed to the heart of the majority of men, while theology, expounding the same truths in real terms without metaphors, was beyond the capacity of the minds of most of them.
The rational metaphors of Ibn Sina, forcefully and coherently argued in the context of his philosophical system, confronted the Ismaili prophetic theology with a grave challenge. There is no record, however, of any direct Ismaili response, critical discussion or refutation of it for over a century. Nasir-i-Khusraw in Kitab Jami‘ al-hikmatayn (composed in 463 AH /1070 CE) in which he set forth a concordance of the twin wisdoms, Greek philosophy and Ismaili theosophy, did not take note of the views of Ibn Sina and the Muslim Peripatetics in general, though his presentation of Ismaili teachings clearly confirmed its scriptural, prophetic origins. Sometime later, the need of the human mind for a divinely guided teacher (mu‘allim) and the inadequacy of reason were restated in ardent, though tedious, argumentation in the Four Chapters (Fusul -i arba‘a) ascribed to Hasan-i Sabbah, the founder of the Nizari branch of the Ismailis. The thesis of divinely guided teaching (ta‘lim), though obviously rooted in earlier Ismaili and Shi‘i thought, become so central in Nizari doctrine that the followers of Hasan-i Sabbah’s “New Summons” (da‘wa jadida) came to be known as the Ta‘limiyya. As if to underline the specific relevance of the necessity of Ta‘lim to theology, Hasan-i Sabbah spoke of the failure of reason in respect to the knowledge of God and of the need of prophecy for the true confession of unity (tawhid).
The arguments of Hasan-i Sabbah were quoted most extensively by al-Shahrastani (d. 548 AH /1153 CE) in his Book of Religions and Doctrinal Schools (K. al-milal wa’l-nihal). Al-Shahrastani was evidently keenly interested in them. Though widely renowned as an outstanding Ash‘ari theologian with an open minded interest in all religions and philosophies, he was known by some of his contemporaries to incline secretly to Nizari Ismailis teachings and to spread its message.3 He himself mentions in his still unpublished Qur’anic commentary,4in which he employed specific Ismaili terminology and methods of interpretation, how his teacher in exegesis had revealed to him certain “noble words of the Family of the Prophet and their followers” which “pointed to hidden mysteries and solid foundation of Qur’anic sciences.” He searched then for the “truthful ones” (al-Sadiqin) and found “a righteous servant of God” (‘abd min ‘ibad Allah al-Salihin) who taught him the true principles of Qur’anic exegesis. This latter teacher, whose name al Shahrastani does not mention, was probably an Ismaili. Though nothing more is known about his concrete relations with Alamut, several of his extant works attest that he espoused Ismaili views during all of his mature life. In one of his still unpublished works, entitled The Wrestling Match (al Musar‘a)5 , he undertook to refute the metaphysics of Ibn Sina on the basis of what he termed the Norm of Prophethood (mi‘yar al-nubuwwa). In substance, his own position agreed fully with traditional Ismaili theology.
Al-Shahrastani criticises Ibn Sina’s comprehensive concept of being (wujud) which includes both God, the Necessary Being, and the contingent world. This concept, he suggests, tends to turn being into a genus or a genus-like concomitant whose parts are distinguished by differentiae and thus are necessarily composed. In order to escape this consequence, Ibn Sina maintained that ‘being’ applied to God and the contingent world analogically (bi’l-tashkik), rather than univocally (bi’l-tawatu’), and thus does not comprise them in equal manner. Even with this analogical concept of being, Ibn Sina’s Necessary Being, al-Shahrastani argues, can be shown to contain multiplicity. The term wujud, he insists, cannot be applied to God either univocally or analogically, but only equivocally (bi’l-ishtirak). Used in reference to God, its meaning has nothing in common with its meaning in contingent things. God is the Necessary Being only in the sense that He gives being to others and takes it away from them. Similarly all other names and attributes used in respect to God must be understood equivocally. God is truth (haqq) in the sense that He makes the truth valid and falsehood void (yuhiqqu’ l-haqq wa yubtilu’ l-batil). He is living in the sense that He gives life and death. Opposites like being and non-being, unity and multiplicity, knowledge and ignorance, life and death, good and evil, power and impotence are like disputants in a lawsuit (mutahakimat); God is above them as their judge (hakim). Ibn Sina’s attempt to prove the existence of God on the basis of his comprehensive concept of being is thus futile. In reality, there is no need for a proof of God; for God is too apparent to require any indication for his presence. Knowledge of God indeed rests on innate disposition (fitra).To deny Him is to deny oneself. He who denies the Absolute Judge, judges himself and confirms Him by his judgement. This is the reason why the prophets have confined themselves to preaching the unity of God, the denial of partners and equal opponents, since a proof of God was unnecessary.
Al-Shahrastani objects to Ibn Sina’s thesis that “from the One can proceed only a single one”, i.e. the First Intellect. Rather, God is the originator of everything and all things have to be put in equally direct relation to Him without the mediacy of an Intellect, Soul or Nature. The unity of God is indeed not the unity of the number one, of a whole or a sum, of genus, species or individual, unity, multiplicity and opposites equally proceed from Him. This is confirmed by the Holy Qur’an which places the creatures generically as well as individually in immediate relation with God. Thus in the verse (lxxviii 38), “On the day when the Spirit and the angels will stand in a row [before God]”, the Spirit (ruh) means the First, Active Intellect and the angels mean the incorporeal lords of the spheres (al-mufariqat al-mudabbirat amran). All things must therefore equally be put into immediate relation with God whether they have proceeded from Him directly and by primary intention (ibi’l-qasd al-awwal) or not. For in their contingency, they are all in equal need of the Originator, however their ranks may differ in other respects.
Ibn Sina’s doctrine that God is in essence under three aspects, intelligence, intellecting and intelligible, is equally repudiated by al-Shahrastani as implying a trinity in God similar to the trinity affirmed by the Christians. Criticising and rejecting Ibn Sina’s complex theory of the knowledge of God with its distinction between the modes of His cognition of Himself, of universals and of particulars, al-Shahrastani insists that the knowledge of God equally includes universals and particulars and postulates a hierarchy of knowledge and reasoning. The human capacity of reasoning is higher than that of animals, and the knowledge of angels is superior to that of men. Reason and knowledge apply to men and angels only equivocally. The cognition of angels does not depend on representation and affirmation, definition and syllogism like that of men. The knowledge of God is beyond all these methods of cognition.
Al-Shahrastani denies Ibn Sina’s thesis of the eternity of the world. Against the statement of Ibn Sina that “the world exists with the existence of the Creator and continues to exist with His duration”, he maintains that the concepts of existence and duration are equivocal in relation to God and the world. God is absolutely extratemporal, as He is extraspacial, while the duration of the physical world is in time. Time, being tied to the revolution of the spheres, exists only below the spiritual world of immaterial beings. Against the Aristotelian doctrine, al-Shahrastani argues that the infinite sequence is as impossible in the material world as the infinity of space. Thus Ibn Sina’s thesis of the infinite revolution of the spheres which he postulates as the cause of the eternity of the realms of nature (mawalid) is untenable. The basic error of Ibn Sina and his followers in this question is that they view the world as an emanation from God which is necessitated by His Self (dhat). Thus they describe God in relation to the universe primarily as its Necessitator (mujib). The world then appears as an accidental, unintentional consequence of His essence. God is, however, in relation to the world primarily its giver of existence (mujid), not of necessity, and revealed scripture describes His acting towards it with terms like ‘option’ (ikhtiyar), ‘will’ (irada), ‘creation’ (khalq), ‘command’ (amr) and ‘reign’ (mulk).
Finally, al-Shahrastani questions the followers of Ibn Sina as to why the latter considered the Active Intellect, the lord of the sphere of the moon, as the Giver of the Forms through which the human intellect advances from potentiality to actuality and perfection. Why did he not consider anyone of the other intellects of the planetary spheres or the First Intellect or even God Himself to be the Giver of Forms? The lunar intellect is, after all, only in appearance closer to mankind in space. If closeness to mankind is, however, a consideration, could it not rather be that a human intellect which, having reached actuality and being supported with holy power, surpasses all other human intellects, is the Giver of Forms? Could it not be the intellect of the prophet?
Al-Shahrastani’s Ismaili teaching appears to have been a major factor in the temporary embracing of Ismaili-Islam by the great Shi‘i philosopher and astronomer, Nasir al-Din al-Tusi (d. 676 AH / 1274 CE). In an autobiographical account written while he adhered to Ismaili teachings, al-Tusi himself mentions that al-Shahrastani, to whom he refers with the Ismaili title da‘i al-du‘at was the teacher of his father’s uncle and teacher, and that it was his father who introduced him to the religious beliefs and ideologies of mankind. He further describes how he, after studying theology (kalam) and philosophy, came to realise that human intellect could actually advance from potentiality to actuality only under the influence of another, perfect intellect and a divinely guided teacher (mu‘allim). This teacher he hoped to find in joining the Ismailis.
Al-Tusi, it is known, later abandoned Ismailis teachings and, within a wide range of scholarly and scientific activities, became one of the chief supporters and commentators of the philosophy of Ibn Sina. He now wrote a rebuttal to al-Shahrastani’s criticism of Ibn Sina’s metaphysics in which he upheld and defended the latter’s position point for point. His argumentation is based purely on reason, and he dismissed al-Shahrastani’s appeals to scriptural evidence and to the “Norm of the Prophets” as irrelevant to rational disputation.
Nasir al-Din al-Tusi’s own theology as set forth particularly in his Tajrid al-‘aqa’id, in which he combined the basic tenets of the Imami creed with the philosophy of Ibn Sina, has had a great and lasting influence on scholastic theology, Sunni as well as Shi‘i, in eastern Islam. The definition of God as Being, the Necessary Being, introduced in scholastic theology already by al-Ghazali and Fakhr al-Din al-Razi, now came to dominate the thought of theologians and philosophers alike, and the cosmological proof of God was set forth in countless variations.
The concept of the analogical being of God and the world prevailed also in the great renaissance of philosophy in the school of Isfahan of the Safavid age which combined varied strands of rational, scriptural, and mystical thought in new syntheses. Yet, the idea of a God beyond reason and being did not disappear in the concealment to which the Ismailis had more and more been condemned. Henry Corbin has recently noted the profound accord of the theological views of Mulla Rajab ‘Ali Tabrizi (d. 1080 AH/ 1669-70 CE) and his school with classical Ismaili teaching.6‘Ali, a student of Mir Findiriski, rejected the prevailing doctrine that existence applies analogically to God and the contingent world and maintained that it could only equivocally be attributed to God. In accordance with this thesis, he adhered to the via negationis in respect to the attributes of God. Although he does not mention the Ismailis among those who held these views before him, affiliation of his ideas to Ismaili thought is likely. In setting forth his position, he quotes a saying ascribed to Imam Muhammad al-Baqir affirming that God could be called knowing and powerful only because He gives knowledge to the knowing and power to the powerful. This statement of the Imam was, according to al-Shahrastani, transmitted by the Ismailis in support of their own doctrine. Rajab ‘Ali’s views were reaffirmed and elaborated by his numerous students, most famous among them Qadi Sa‘id Qummi (d. 1103 AH / 1691-92 CE). Qadi Sa‘id in his mystically oriented theology upheld his teacher’s thesis of the equivocal meaning of the term being in relation to God and emphasised God’s transcendence of reason and intelligibility. Denying that the intellect can attain knowledge of God, he held that consciousness of God must arise in the heart on the basis of the innate natural disposition of the man. He relied on the double negation of the divine attributes propounded by Abu Ya‘qub al-Sijistani and discussed the unity of God in terms close to Ismaili teaching, denying its arithmetic quality.
Another student of Rajab ‘Ali, Qawam al-Din Muhammad Razi, carried the principle of God’s transcendence in respect of being even further, by denying that God could be called the Necessary Being. Still later, Corbin also noted, the same tradition of suprarational theology was represented in the work of Shaykh Ahmad al-Ahsa’i (d.1241 AH / 1826 CE), the founder of the Shaykhi school, and in the system of the philosopher and theosophist Sayyid Ja‘far Kashfi (d. 1267 AH / 1850-51 CE). The study of the thought of these schools has hardly begun, and it would be premature to assess their full significance and interrelationship. Yet the recurrence of the appeal of a prophetic, suprarational theology which views God as absolutely transcending both reason and being for so long after “the Ismaili century”, clearly testifies to its deep roots in the religious thought of Islam.
 In his “Mutanabbi devant le siècle ismaëlien de l’Islam”, in Mém. de l’Inst Français de Damas, 1935, p.
 For the following see in particular Paul Walker, “An Ismaili Answer to the problem of Worshipping the Unknowable, Neoplatonic God”, in American Journal of Arabic Studies, II, 1974, 7-21, and idem, “The Ismaili Vocabulary of Creation”, in Studia Islamica, XL, 1974, 75-85.
 See M.T. Daneshpajhuh, Dai al-Du‘at Taej al-Din Shahrastana, in Nama-yi Astan-i Quds, VI1/2, 1346, 71 ff., VIII/4, 1347, 61.ff.; and in general for the following W. Madelung, As-Sahrastanis Streitschrift gegen Avicenna und ihre Widerlegung durch Nasir ad-Din at-Tusi, in Akten des VII. Kongresses für Arabistik und Islamwissenschaft, ed. A.Dietrich, Gottingen, 1976, 250-9.
 This is now published as Keys to the Arcana: Shahrastani’s Esoteric Commentary on the Qur’an by Toby Mayer, The Institute of Ismaili Studies in association with Oxford University Press, 2009
The Book is now published by The Institute of Ismaili Studies, under the title “Struggling with the Philosopher: A Refutation of Avicenna’ s Metaphysics” I B Tauris in association with The Institute of Ismaili Studies, 2001.
 H. Corbin, introd. to Anthologie des Philosophes Iraniens, ed. S.J. Ashtiyani, Vol. I, Tehran Paris, 1972, 98 ff. For the following, see also H. Corbin, En Islam Iranien, Paris, 1972, IV, chapter 3, and idem, introd. to Anthologie des Philosophes Iraniens, ed. S.J. Ashtiyani, Vol. II, Tehran Paris, 1975, 91 ff.