Avicenna

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Avicenna — the Latinized name of Abū ʿAlī al-Ḥusayn ibn ʿAbd Allāh ibn Sīnā, known in the Islamic world simply as Ibn Sīnā — was a Persian philosopher and physician active across the eastern lands of the Abbasid world in the late tenth and early eleventh centuries. He is conventionally dated c.980 to 1037. More than any single figure he gave medieval Islamic philosophy its systematic shape, and through Latin translation he became one of the authorities the Christian schoolmen had to answer. To the later tradition he was the al-shaykh al-raʾīs, the Preeminent Master — and where Aristotle was the First Teacher of philosophy, Ibn Sīnā was the architect who finished the building.

The life and the autobiography

The biography is partly his own. A short autobiography, dictated to his pupil and amanuensis Abū ʿUbayd al-Jūzjānī and continued by that pupil after the master’s death, remains the most extensive source for his life. It records a precocious youth in the region of Bukhara, where the boy gained access to the library of the Samanid court and read his way through the available sciences while still young. By his own account he had read Aristotle’s Metaphysics forty times and all but memorized it without grasping its aim, until a short commentary by al-Farabi — the Second Teacher, whose reworking of the Greek inheritance Ibn Sīnā inherited and surpassed — unlocked the whole. He gave thanks and, the story goes, distributed alms to the poor.

The remainder was a working life spent in the service of a sequence of princes as the political map of the Iranian east fractured: Gurganj in Khwārizm, then Jurjān, Rayy, and Hamadān, where he served and was for a time imprisoned, and finally Isfahan under the Kakuyid ruler ʿAlāʾ al-Dawla. He composed in the intervals of court duty, on horseback and under arrest, dictating to students at night. He died at Hamadān in 1037 and was buried there. The portrait that emerges is of a mind of extraordinary speed and confidence, certain that the inherited philosophy could be made into a single demonstrated science and that he was the man to do it.

The Canon and the Healing

Two works carried his name farthest. The Canon of Medicine (al-Qānūn fī l-ṭibb) organized Greek and Arabic medicine — Galen, Hippocrates, and the Arabic physicians before him — into a single systematic encyclopedia of the human body, its humors, its diseases, and its remedies. Translated into Latin at Toledo by Gerard of Cremona in the twelfth century, the Canon became the standard medical textbook of the European universities and was still being taught in them well into the seventeenth century, a span of authority few books of any kind have matched.

The Book of Healing (al-Shifāʾ) — despite the title, a vast philosophical summa covering logic, natural science, mathematics, and metaphysics rather than a medical work — was the principal vehicle of his thought. He recast its arguments in shorter compass in The Salvation (al-Najāt), in the Persian Dāneshnāme-ye ʿAlāʾī (Philosophy for ʿAlāʾ), and, late in life and in a more allusive and compressed register, in Pointers and Reminders (al-Ishārāt wa-l-tanbīhāt), the work on which much of the later Islamic commentary tradition would hang. He spoke too of an “Eastern philosophy” (al-mashriqiyyūn) freed from the conventions of the schools — a tantalizing phrase whose precise content is debated, since the work that would have carried it survives only in fragments.

Being, essence, and existence

At the center of the metaphysics lies a distinction that scholarship credits him with making decisive: between what a thing is and that it is — essence (māhiyya) and existence (wujūd). To know what a thing is — to grasp its definition — is not yet to know that it exists; existence is something further, not contained in the essence but added to it, received from outside. A horse considered simply as a horse is neither one nor many, neither existent nor nonexistent, neither universal nor particular: equinity, in the formula later much quoted, is just equinity. Whether it exists in the world, and whether it is the single idea in the mind or the many horses in the field, are conditions that attach to the essence rather than belonging to it. Existence, for everything in the world, is in this sense an addition to the nature it specifies.

From this Ibn Sīnā built a modal ontology that became the grammar of metaphysics after him. Every existent is one of three things. It is impossible, and then it is nothing. It is possible in itself (mumkin) — its essence does not by itself require that it be, so that, considered alone, it is poised indifferently between existence and nonexistence and needs a cause to tip it into being. Or it is necessary in itself (wājib) — its existence belongs to it by its own nature and requires no cause. Everything in the world is of the second kind: a contingent being whose existence is borrowed. Follow the chain of borrowers and it cannot borrow forever; the series of the merely possible, however long, could never of itself produce a single actual thing. It must therefore terminate in a being whose existence is not received but is its own essence — the Necessary Existent (wājib al-wujūd bi-dhātihi), from which all else proceeds.

This is the proof from contingency, which the later tradition honored as the “demonstration of the truthful” (burhān al-ṣiddīqīn) because it argues to God not from motion or from the design of the world but from the bare concept of being itself. The Necessary Existent so reached is absolutely simple: in it there is no distinction of essence and existence, no composition of any kind, for anything composite would depend on its parts and so be caused. It is one, because two necessary beings would have to differ, and to differ is to have a feature one lacks, which is a kind of limitation a necessary being cannot have. Its single positive attribute is, in effect, that it is. Everything else that is said of it — that it knows, wills, is good — must be understood without compromising that simplicity. The doctrine is plainly indebted to the apophatic strain of Neoplatonism, the negative theology that guards the transcendence of the One; but Ibn Sīnā has rebuilt it on the foundation of his own analysis of being, so that the simplicity of God follows from the metaphysics of existence rather than being asserted of a One beyond being.

Emanation and the ten intellects

From this single source the orders of being emanate in a graded series. Because the Necessary Existent is one and simple, what proceeds immediately from it can only be one — a first separate Intellect. That intellect, in turn, is the site of a duality: contemplating its source it apprehends the Necessary Existent, and reflecting on itself it apprehends its own essence as merely possible. From this internal multiplicity the next stage of the cosmos unfolds. In thinking its principle each intellect generates a further intellect; in thinking the necessity its principle confers on it, it generates the soul of a celestial sphere; and in thinking its own contingency, the body of that sphere. The process repeats down a hierarchy of ten intellects, the Aristotelian heavens turning beneath them, an architecture visibly continuous with the Islamic Neoplatonism that had reached Arabic readers partly under Aristotle’s name — above all through the so-called Theology of Aristotle, in fact a paraphrase of Plotinus, whose emanative scheme al-Farabi had already fitted to an Aristotelian cosmos.

The tenth and last of these is the Active Intellect (al-ʿaql al-faʿʿāl), and with it the chain reaches our world. It is the giver of forms (wāhib al-ṣuwar): the separate source from which the forms of sublunar things flow into suitably prepared matter, and from which the human mind receives the intelligibles it comes to think. On this account the world is not made by a craftsman shaping matter from without, nor created at a moment in time; it flows eternally and necessarily from the overflowing fullness of the First, the way light flows from a source or a conclusion from its premises. Creation is timeless dependence, not a beginning.

The soul and the floating man

The human rational soul, on Ibn Sīnā’s account, is immaterial, individual, and survives the death of the body, perfected — or impoverished — by the knowledge it has gathered. Between the senses and the intellect he interposed a careful map of the faculties: the five external senses, and five internal senses housed in the brain — the common sense that gathers the reports of the others, the form-bearing faculty that retains their images, the imagination that combines and divides them, the estimative faculty (wahm) by which an animal grasps an unsensed intention such as the lamb’s perception of hostility in the wolf, and the memory that stores such judgments. Above these stands the rational soul proper, which alone reaches the universal.

Knowing, for Ibn Sīnā, is finally an illumination from above: the human intellect, moving from potentiality to act, is actualized when it makes contact (ittiṣāl) with the Active Intellect and receives the intelligible form. What we call discovery is the mind hitting upon the right middle term of a syllogism — and the swiftness with which a given mind seizes that term is a native gift Ibn Sīnā calls intuition (ḥads). Some minds need to be taught every step; rarer ones leap to the conclusion; and at the limit there is a mind so perfectly disposed that it grasps almost all the middle terms at once, with little or no instruction. That limiting case is the prophet, whose prophecy is thus not a suspension of nature but its summit — the highest reach of human intellection, joined to an imagination strong enough to clothe the truths it receives in images and a soul able to act upon matter. The continuity of revelation and reason that al-Farabi had drawn, Ibn Sīnā grounded in a theory of mind.

To show that the soul is something in its own right, independent of the body, he framed the argument that the medieval West would call the “floating man.” Imagine a person created in an instant, fully formed but suspended in empty air, eyes veiled, limbs held apart so that they touch nothing, deprived of every sensation whatever. Such a person, Ibn Sīnā contends, would still affirm his own existence — would be certain that he is, while affirming nothing of his body, which he does not feel. What one can affirm while denying everything bodily cannot be the body; the self of which each of us is immediately aware is therefore not material. The thought experiment is among the most discussed in the history of philosophy, and the resemblance to later European arguments about the self-certainty of the thinking subject has not gone unnoticed, though Ibn Sīnā’s purpose was to isolate the substance of the soul, not to found knowledge on doubt.

The visionary recitals

Alongside the demonstrative summae Ibn Sīnā wrote a small set of symbolic narratives that read the same cosmos as a journey. In Ḥayy ibn Yaqẓān (“Alive, Son of the Awake”) a sage of radiant agelessness meets the narrator and offers to guide him across the regions of the world; the sage is the Active Intellect personified, and the landscape is the structure of being the metaphysics had laid out, now traversed rather than proved. The Bird (Risālat al-Ṭayr) tells of a flock snared and caged and of the soul’s flight back toward its origin, and the fragment Salāmān wa Absāl turns on a like motif of ascent. The orientalist Henry Corbin, whose 1960 study Avicenna and the Visionary Recital recovered these texts for modern readers after he found a Persian commentary on Ḥayy ibn Yaqẓān in an Istanbul library, read the three as an initiatory cycle, an inner counterpart to the outer system in which the impersonal scheme of intellects becomes a personal itinerary of the soul. These recitals — distinct from the later desert-island novel of the same title by the Andalusian Ibn Ṭufayl, which borrowed its names from Ibn Sīnā’s recitals but tells a wholly different story — are the slender bridge by which later esoteric and mystical readers have claimed Ibn Sīnā for an inner tradition, drawn to his accounts of prophecy, intuition, and the soul’s return. The connection is genuine in those texts, though slight beside the systematic philosopher the manuscripts mainly preserve.

The two afterlives: Islam and the Latin schools

His influence ran in more than one direction at once. Within the lands of Islam he became the philosopher to refute or absorb. A generation after his death al-Ghazālī (1058–1111), in The Incoherence of the Philosophers (Tahāfut al-falāsifa), examined twenty theses of the falsafa Ibn Sīnā represented and judged three of them not merely mistaken but outside the faith: the eternity of the world, the claim that God knows only universals and not particulars in their particularity, and the denial of bodily resurrection. The charge sharpened a fault line between revealed religion and Greek-derived demonstration that ran through Islamic intellectual life thereafter — though al-Ghazālī, who absorbed far more of the logic and metaphysics he attacked than the polemic admits, did as much to transmit Avicennan ideas as to bury them. (His own account of that crisis survives in the autobiographical Deliverer from Error.) Later thinkers built on Ibn Sīnā even while quarreling with him: the Illuminationist current of Suhrawardī transposed his metaphysics into a philosophy of light, and centuries afterward Mullā Ṣadrā’s transcendent theosophy would invert his most famous distinction, giving primacy to existence over essence while still arguing on the ground he had cleared.

In the Latin West the reception was equally consequential. At Toledo in the second half of the twelfth century the philosophical parts of the Shifāʾ — the De anima, the Metaphysica (the Liber de philosophia prima), the Physica, and parts of the logic — were translated into Latin by Gerard of Cremona and by the archdeacon Dominicus Gundissalinus working with the Jewish scholar Avendauth (Abraham Ibn Daud), who rendered the Arabic into Castilian for Gundissalinus to put into Latin. “Avicenna” thereby entered the scholastic curriculum as a living voice. His distinction of essence and existence became the hinge of Thomas Aquinas’s early treatise On Being and Essence; his description of God as the being whose essence is its own existence passed into the same author’s proofs; and his account of the giver of forms (in Latin, the dator formarum) was taken up, tacitly, by Albert the Great and others. Through Ibn Sīnā the question of what the mind first apprehends — being, as the primum cognitum — became a standing theme of Latin metaphysics, and his analysis of essence “in itself” fed the later debates over universals and the common nature that occupied Duns Scotus. The schoolmen took up his arguments, adapted them, and contested them; the synthesis of an “Avicennized Augustinianism” in figures such as William of Auvergne is one measure of how deeply the Persian master had been read.

What the record holds steadiest is the architecture itself — a world hung from a single necessary being, the orders of intellect descending from it by necessity, the soul ascending back toward the light that gives it its forms, the whole reasoned through from the bare concept of existence to its end.

Texts and scholarship

The critical reconstruction of Ibn Sīnā’s thought is the work of modern philology, and the indispensable foundation is Dimitri Gutas, Avicenna and the Aristotelian Tradition: Introduction to Reading Avicenna’s Philosophical Works (Leiden: Brill, 1988; second, expanded edition 2014), which reconstructs the intellectual biography from the autobiography outward and argues for the fundamentally Aristotelian self-understanding of a philosopher long read as a mystic. For the metaphysics in detail, Amos Bertolacci’s article “Ibn Sina’s Metaphysics” in the Stanford Encyclopedia of Philosophy (plato.stanford.edu) lays out the science of being qua being, the essence–existence distinction, and the proof of the Necessary Existent with full reference to the Cairo edition of the Ilāhiyyāt; the companion overview “Ibn Sina [Avicenna]” (plato.stanford.edu) treats the life, the works, and the psychology, including the floating-man argument and the theory of intuition, and its bibliography is the standard guide to the editions and the secondary literature. Jon McGinnis, Avicenna (Oxford University Press, 2010), is the leading single-volume philosophical study in English, and Peter Adamson’s Philosophy in the Islamic World (Oxford University Press, 2016) sets him within the wider arc of falsafa from al-Kindī forward; the same author’s reception study on the influence on the Latin West is summarized in the Stanford Encyclopedia entry on the influence of Arabic and Islamic philosophy on the Latin West.

For the visionary side, the foundational study remains Henry Corbin, Avicenna and the Visionary Recital, translated by Willard R. Trask (Bollingen Series; Pantheon, 1960; reissued by Princeton University Press), which prints the three recitals with the Persian commentary on Ḥayy ibn Yaqẓān (press.princeton.edu). The Neoplatonic stream into which Ibn Sīnā’s emanative cosmos drains can be read in the primary texts the Library hosts: Stephen MacKenna’s English of Plotinus’s Enneads (1917–1930), the Theology of Aristotle’s ultimate source. The crisis his philosophy provoked is preserved in the Library’s English of al-Ghazālī’s autobiography, Claud Field’s 1909 Confessions of Al Ghazzali, the personal record of the thinker who arraigned the falsafa Ibn Sīnā had perfected.

→ In the library: MacKenna — Plotinus: The Enneads (1917–1930) · Field — The Confessions of Al Ghazzali (1909)

→ Related: Aristotle · Neoplatonism · Emanation · The One · Al Farabi · Arabic Falsafa Islamic Philosophy · Islam · Thomas Aquinas · Suhrawardi · Islamic Neoplatonism