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Avicenna (980–1037)


Avicenna, whose full name was Abū ʿAlī al-usayn ibn ʿAbd-Allāh ibn Sīnā, was the most renowned and influential philosopher of medieval Islam. He was a Persian, born near Bukhara, then the capital of the Persian Samānid dynasty. His father was a partisan of the heterodox Ismāʿīlī sect, whose theology drew on current popularized Neoplatonism. As a boy, Avicenna was exposed to Ismāʿīlī doctrine but found it intellectually lacking. He received some of the basic Islamic religious education, then studied logic, mathematics, the natural sciences, philosophy, and medicine, mastering these subjects by the age of eighteen. A certain al-Nātilī introduced him to logic, geometry, and astronomy, but Avicenna was largely self-taught. He records that he was able to fathom Aristotle's Metaphysics only after a chance discovery of a commentary on it by al-Fārābī (Alfarabi). Appointed physician at the Samānid court, he intensified his studies at its excellent library. Thereafter, he states, he added little to his stock of learning but deepened his understanding of what he had acquired.

In 999 Samānid rule disintegrated with the onslaught of the Turkish Ghaznawid dynasty. Avicenna left Bukhara to roam the cities of Transoxania and Iran, serving local warring princes. Between 1015 and 1022 he acted as both vizier and physician to the ruler of Hamadan; after the latter's death he was imprisoned but was released four months later when ʿAlā al-Dawla, the ruler of Isfahan, temporarily occupied the city. Soon afterward, disguised as a dervish, Avicenna left Hamadan for Isfahan, where he spent the rest of his life as physician to ʿAlā al-Dawla. This was a relatively peaceful period of his life, during which he undertook astronomical investigations. A serious interruption occurred in 1030, when the Ghaznawids sacked Isfahan and some of Avicenna's works were pillaged and lost. He died in Hamadan while accompanying his patron on a campaign against that city.

Over a hundred of Avicenna's works have survived, ranging from encyclopedic treatments to short treatises and covering, apart from philosophy and science, religious, linguistic, and literary matters. He wrote some works in Persian, of which the Dānishnāma-yi ʿAlāʾī ("The Book of Science Dedicated to ʿAlā al-Dawla") is the most important. Most of his works, however, are in Arabic. His chief medical work is al-Qanūn fi al-Tibb ("The Canon of Medicine"), a synthesis of Greek and Arabic medicine which also includes his own clinical observations and views on scientific method. The most detailed philosophical work is the voluminous al-Shifāʾ ("The Healing"). Al-Najāt ("The Deliverance") is largely a summary of al-Shifāʾ, although there are some deviations. Al-Ishārāt wa al-Tanbīhāt ("The Directives and Remarks") gives the quintessence of Avicenna's philosophy, sometimes in an aphoristic style, and concludes with an expression of his mystical esoteric views, a part that relates to certain symbolic narratives which he also wrote.


Avicenna forged a comprehensive philosophical system that owed a great deal to Aristotle, but his system cannot be strictly called Aristotelian. In both his epistemology and his metaphysics he adopted Neoplatonic doctrines but formulated them in his own special way. There were other Greek influences: Plato on his political philosophy; Galen on his psychology; the Stoics on his logic. Nearer home was the influence of Islamic theology and philosophy. The theologians had stressed the contingent nature of things, subjecting Aristotelian causal theory to severe logical and empirical criticism. Avicenna undertook to meet this criticism and attacked the theologians' formulation of the notion of contingency, but he nonetheless was influenced by it. The Islamic philosopher who influenced him most was al-Fārābī; Avicenna adopted al-Fārābī's concept of the identity of divine essence and existence, and developed his dyadic emanative system into a triadic scheme. As both metaphysician and political thinker, Avicenna interpreted the Islamic religion in terms of his own system. Whether this religion remains "Islamic" when so interpreted is a debatable point, but it conditioned the way Avicenna formulated his philosophy.


Although Avicenna's system rests on his conception of the Necessary Existent, God, he held that the subject matter of metaphysics is broader than theology. As distinct from physics, which considers moving things "inasmuch as they move," metaphysics is concerned with the existent "inasmuch as it exists." We arrive at the Necessary Existent by first examining the attributes of the existents. Avicenna undertook such examination in detail, drawing those distinctions which greatly influenced Latin scholastic thought. One such distinction is that between a universal like "horse," by definition predicable of many instances, and a universal like "horseness," in itself outside the category of such predication; considered in itself, horseness is simply horseness, neither one nor many. Related to this is the fundamental distinction between essence and existence.

If we examine any existing species, we find nothing in its essence to account for its existence. In itself, such an existent is only possible: it can exist or not exist. From what it is, we cannot infer that it exists, although in fact it exists. Something has "specified" it with existence; and this something, argued Avicenna, must be its necessitating cause. If it were notif it were a cause that may or may not produce its effectwe would have to suppose another cause; and if this cause were not necessitating, yet another; and so on ad infinitum. But an infinity of such causeseven if allowedwould not specify the possible with existence. Hence, such an existent must be necessitated by another, by which Avicenna meant that its existence is the consequence of the essence of another existent. The theory involved here is that of essential causality, where causal action is a necessary attribute of a thing's essential nature and where cause and effect coexist. Existents form a chain of such essential causes; and since these coexist, the chain must be finite. Otherwise it would constitute an actual infinite, which Avicenna deemed impossible. The chain must proceed from an existing essence that does not derive its existence externally. This is God, the Necessary Existent, who, Avicenna attempted to demonstrate, must be eternal, one, and simple, devoid of all multiplicity. Since God, the necessitating cause of all the existents, is eternal, his effect, the world, is necessarily eternal.

The world emanates from God as the consequence of his self-knowledge. Self-knowledge, however, does not imply multiplicity in the knower; nor does multiplicity proceed from God directly. God's act of self-knowledge necessitates the existence of one intellect. Multiplicity proceeds from this intellect which undergoes three acts of awareness, corresponding to the three facts of existence it encounters: (1) God's existence as necessary in itself; (2) the intellect's own existence as necessitated; (3) the intellect's own existence as only possible in itself. These three acts of awareness necessitate the existence of three thingsanother intellect, a soul, and the first heaven, respectively. The second intellect, in turn, undergoes a similar cognitive process, necessitating another triad; the third intellect, yet another; and so on down to the sphere of the moon. The last intellect thus generated is the Active Intelligence, whose acts of cognition necessitate the world of generation and corruption.

Avicenna's cosmology was oriented toward the Ptolemaic system as modified by some of the Islamic astronomers, who, in order to explain the precession of the equinoxes, added another heavenly sphere beyond that of the fixed stars, and Avicenna inclined toward regarding the number of intellects as ten. He was not dogmatic on this point, however, leaving the question of the number of intellects adjustable to changes in astronomical and cosmological theory. What he insisted on was that the number of intellects should be at least equal to the number of heavens.

In this scheme Avicenna attempted to make precise the relation of the celestial intellects to God, something left uncertain in Aristotle. According to Avicenna, the intellects derive their existence from God and are arranged in an ontological and normative hierarchy corresponding to their proximity to God. God, for him, is not only the prime mover but also the cause of existence. The celestial intellects, in turn, although deriving their existence from God, cause other existents and act as teleological causes. Thus, in each of the triads the heavenly body is moved by its soul through the soul's desire for the intellect. The souls differ from the intellects in that they have a material aspect enabling them to have direct influence over the particulars in the sublunar world and to know them in their particularity. Neither God nor the celestial intellects have this direct influence and know these particulars only "in a universal way."

the human soul

According to Avicenna, both the human soul and the rational knowledge it acquires are emanations from the Active Intelligence. As such, the body "receives" the soul and the soul "receives" rational knowledge. Certain combinations of formed matter induce the reception from the Active Intelligence of the vegetative soul. Other combinations induce, in addition to this, the reception of the animal soul; and others, in addition to these two, induce the reception of the rational soul, with its practical and theoretical aspects. The human rational soul is an individual, indivisible, and immaterial substance that does not exist as an individual prior to the bodyAvicenna denied the theory of transmigration. Further, it is created with the body, not "imprinted" on it. The body is no more than the soul's instrument, which the soul must use for perfecting itself through the attainment of theoretical knowledge; this involves complete control of the animal passions. Souls inherently incapable of attaining theoretical knowledge can still control the body and live pure lives by adhering to the commands of the revealed law. With the body's corruption (death), the soul separates to exist eternally as an individual. Souls that have led pure lives and have actualized their potentialities continue in eternal bliss, contemplating the celestial principles. The imperfect souls, tarnished by the body, continue in eternal torment, vainly seeking their bodies, which once were the instruments of their perfection.

Avicenna denied bodily resurrection but insisted on the Soul's individual immortality. To begin with, he held that the immaterial is incorruptible. Moreover, he was convinced not only of the soul's immateriality but also of its individuality. He argued for both these points simultaneously: When one refers to himself as "I," this cannot be a reference to his body. If a man were to come into being fully mature and rational but suspended in space so that he was totally unaware of his physical circumstances, he would still be certain of one thinghis own existence as an individual self.

Theoretical knowledge consists in the reception of the intelligibles from the Active Intelligence. The primary intelligibles, the self-evident logical truths, are received by men directly, without the need of the soul's preparatory activities on the sensory level. The secondary intelligibles, concepts and logical inferences, whose reception is limited to people capable of demonstrative knowledge, normally require preparatory activities involving the external and internal sensessensation, memory, imagination, estimation, and cogitation, or imaged thinking. Avicenna assigned special faculties and physiological places to these activities. The human intellect undergoes various stages in its acquisition of the intelligibles. At first it is a material intellect, a pure potentiality analogous to prime matter, ready for the reception of the intelligibles. With the reception of the first intelligibles it becomes the intellect with positive disposition. When it is in the act of receiving the secondary intelligibles, it becomes the acquired intellect. When an intellect that receives the secondary intelligibles is not engaged in the act of reception, it is termed "the actual intellect."

political and religious philosophy

Avicenna followed al-Fārābī in holding that revealed religion gives the same truths as philosophy but in the symbolic, particular, imaged language that the masses can understand. According to Avicenna, some prophets receive this particular symbolic knowledge directly from the celestial souls. Such reception involves the prophet's imaginative faculty. In a higher form of prophecy that is intellectual, the prophet receives from the celestial intellects not only the first intelligibles, without the need of the soul's preparatory activities, but also the second. Prophetic reception of knowledge thus differs from the philosophical "in manner." It also differs "in quantity." Avicenna suggested that the prophet receives all or most of the intelligibles from the Active Intelligence "all at once." This intellectual revelation is then translated into the language of imagery and divulged to the public. It includes the basic commands of the revealed law, without which man as a political animal cannot survive. Hence, divine goodness must reveal the law at certain moments of discussion through prophets. Prophecy is thus necessary in the sense that it is required for the survival of civilized society and in the sense that it is necessitated by the divine nature. Having argued for the necessity of prophecy, Avicenna proceeded to accommodate Islamic institutions within his philosophical framework.

The high point of Avicenna's religious philosophy is his discussion of mysticism in the Ishārāt. In this work he adopted the language of Islamic mysticism (sufism ) to describe the mystic's spiritual journey to God: Beginning with faith and motivated by desire and love, the mystic undertakes spiritual exercises that first bring him to interrupted glimmerings "of the light of the Truth." These experiences become progressively more frequent and durable until the stage of "arrival" is reached, in which the mystic has a direct and an uninterrupted vision of God. According to Avicenna, there are further stages beyond this, but he declined to discuss them. He also ascribed some of the prophetic qualities to mystics, without implying that all mystics are law-revealing prophets. On the other hand, his language suggests that he held that all prophets are mystics.

logic and demonstrative method

Avicenna inherited the Aristotelian and Stoic logical tradition as expounded by al-Fārābī and the Baghdadi school of logicians but treated his subject more independently. He found the then current classification of syllogisms into "attributive" (categorical) and "conditional" too narrow. Instead, he classified them as "connective" and "exceptive." Connective syllogisms have the form of the categorical, but their premises may consist of combinations of attributive and conditional statements. Similarly, exceptive syllogisms have the form of one of the two types of conditional syllogismsthe conjunctive, corresponding to the modus ponens and the modus tollens, and the disjunctive in which the logical relation is exclusivebut their premises may consist of attributive statements conditionally related, or combinations of conditional and attributive statements. He attempted the quantification of both conjunctive and disjunctive premises, discussed the temporal aspects of quantification in general, and treated the modality of premises and arguments at length.

Although Avicenna held logic to be merely a tool of knowledge and strove to treat it as distinct from philosophy, his discussion of the epistemic status of premises (which carried him considerably beyond anything in Aristotle) rendered his logic philosophically committed; his discussion of demonstrative premises was committed to his epistemology and metaphysics of causality. He followed Aristotle in his treatment of demonstrative inference, distinguishing between demonstrations that give the reasoned fact and those that give the fact. The former involve inference from cause to effect; the latter, inference from effect to cause. He also included in the latter class inferences from one effect to another. This is possible when it has been established that a single cause necessitates two effects; Avicenna gave a medical example of a disease that has two symptoms.

Avicenna's endorsement of the Posterior Analytics extended to much of the Physics. He rejected, however, Aristotle's account of falling bodies, substituting for it a theory of acquired force that was a forerunner of the theory of momentum.

Although some Jewish and Islamic philosophers (Maimonides, ibn Bājja [Avempace], Averroes) showed a preference for al-Fārābī, Avicenna's influence overshadowed the latter's in the Islamic world. The mystical side of his philosophy was elaborated in the illuminationist thought of the philosophers of Persia. The orthodox Ashʿarite theologians who condemned his metaphysics adopted his logic, and his medical works continued to dominate the Islamic world until the emergence of the modern university.

In the Latin West his emanative metaphysics and epistemology blended with the Augustinianism of the Franciscan schools as a basic ingredient of their thought. His influence on Thomas Aquinas was considerable, notwithstanding Thomas's rejection of many Avicennian doctrines. He also greatly influenced the development of logic and science, his Canon of Medicine remaining an authoritative medical text into the seventeenth century.

See also al-Fārābī; Averroes; Cosmology; Ibn Bājja; Islamic Philosophy; Maimonides; Neoplatonism; Plato; Sufism; Thomas Aquinas, St.


There is no collected edition of Avicenna's works in the original. The closest thing to a collection of Persian works consists of Volumes XXXV of the series Silsila-i Intishārāt-i Anjuman-i Āthāri Millī (Publications of the Society of National Monuments). These volumes, published by the University of Teheran, appeared in 1951 on the occasion of Avicenna's millenary.

Critical editions of parts of the al-Shifāʾ, in the original Arabic have been appearing in a series sponsored by the Egyptian ministry of education and supervised by Dr. Ibrahīm Madkūr. The following volumes have appeared: Al-Madkhal ("Isagoge," Cairo, 1952); Al-Khaaba ("Rhetoric," Cairo, 1954); Al-Burhān ("Demonstration," Cairo, 1955); Jawami ʿilm al-Mūsīqā ("Music," Cairo, 1956); Al-Safsata ("Sophistic," Cairo, 1958); Al-Maqūlāt ("Categories," Cairo, 1959); Al-Ilāhīyāt ("Metaphysics," 2 vols., Cairo, 1960); and Al-Qiyās ("Syllogism," Cairo, 1964).

Translations of Avicenna's works include Avicenna on Theology, translated by A. J. Arberry (London, 1951); A Treatise on the Canon of Medicine, translated by O. Cameron Gruner (London: Luzac, 1930); Avicennae de Congelatione et Conglutinatione Lapidum, translated by E. J. Holmyard and D. C. Mandeville (Paris: P. Guethner, 1927); Die Metaphysik Avicennas, translated by Max Horten (New York: R. Haupt, 1907); La métaphysique du Shifāʾ, translated by M. M. Anawati, mimeographed ed. (Quebec, 1952); Le livre de science, translated by Mohammad Achena and Henri Massé, 2 vols. (Paris: Société d'édition "Les Belles Lettres," 1955); Le livre des directives et remarques, translated by A. M. Goichon (Paris, 1955); Psychologie d'Ibn Sînā (Avicenne) d'après son oeuvre Aš-šifaʾ, edited and translated by Jan Bakoš (Prague: Editions de l'Académie tchécoslovaque des Sciences, 1956); Ralph Lerner and Muhsin Mahdi, eds., Medieval Political Philosophy: A Source Book (New York: Free Press of Glencoe, 1963), pp. 95121; and Avicenna's Psychology, translated by Fazlur Rahman (London: Oxford University Press, 1952).

Studies include S. M. Afnan, Avicenna, His Life and Works (London: Allen and Unwin, 1958); M.-T. d'Alverny, "Anniya-Anitas," in Mélanges offerts à Étienne Gilson (Paris: J. Vrin, 1959), pp. 5991; E. G. Browne, Arabian Medicine (Cambridge: Cambridge University Press, 1921); Henri Corbin, Avicenna and the Visionary Recital, translated by W. R. Trask (New York: Pantheon, 1960); M. Cruz Hernandes, La metafísica de Avicena (Granada: University of Granada, 1949); Louis Gardet, La penséd religieuse d'Avicenne (Ibn Sīnā) (Paris, 1951); Étienne Gilson, "Les sources gréco-arabes de l'augustinism avicennisant," in Archives d'histoire doctrinale et littéraire du moyen âge 4 (1929): 5149; A. M. Goichon, La distinction de l'essence et de l'existence d'après Ibn Sīnā (Avicenne) (Paris: Desclée, de Brouwer, 1937), Lexique de la langue philosophique d'Ibn Sīnā (Avicenne) (Paris, 1938), La philosophie d'Avicenne et son influence en Europe médiévale (Paris: Adrien-Maisonneuve, 1944), and Vocabulaires comparés d'Aristote et d'Ibn Sīnā (Paris, 1939).

See also M. E. Marmura, "Avicenna's Theory of Prophecy in the Light of ash ʿarite Theology," in W. S. McCullough, ed., The Seed of Wisdom (Toronto: University of Toronto Press, 1964), pp. 159178, and "Some Aspects of Avicenna's Theory of God's Knowledge of Particulars," in American Journal of Oriental Studies 82 (3) (1962): 299312;S. H. Nasr, Islamic Cosmological Doctrines (Cambridge, MA, 1964), pp. 177281; Shlomo Pines, "La 'philosophie orientale' d'Avicenne et sa polémique contre les Bagdadiens," in Archives d'histoire doctrinale et littéraire du moyen âge 27 (1952): 537; Nicholas Rescher, Studies in the History of Arabic Logic (Pittsburgh: University of Pittsburgh Press, 1963), pp. 7686 and 91105; Djamil Saliba, Étude sur la métaphysique d'Avicenne (Paris, 1926); and G. M. Wickens, ed., Avicenna: Scientist and Philosopher; A Millenary Symposium (London: Luzac, 1952).

Bibliographies include G. C. Anawati, Essai de bibliographie avicennienne (Cairo: Dar al-Marʾarf, 1950), and Yahya Mehdawi, Bibliographie d'Ibn Sīnā (Teheran, 1954).

Michael E. Marmura (1967)

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