Medieval Islamic · 11th c.

Ibn Sina (Avicenna)

ابن‌سینا980–1037Islamic Peripatetics (Mashshāʾī)

Ibn Sina distinguished what a thing is (essence) from that it is (existence). Every contingent being needs a cause, and the chain ends in a being necessary in itself. His "flying man" argues that the soul knows itself without the body.

Central question: How are essence and existence related, and what is the necessary being?
Method: Ibn Sina builds philosophy as a demonstrative system: each science has its own subject and principles, and its conclusions follow by syllogism from what is self-evident or already proven. How Ibn Sina works

wujūd / māhiyya existence wājib al-wujūd the necessary existent al-ʿaql al-faʿʿāl the active intellect al-nafs al-nāṭiqa the rational soul al-kullī the universal

Stated in the text 6
Scholarly consensus 11
Contested reading 3

2 arguments5 works0 quotations checked word for word0 of 22 positions and arguments reviewed by an expert

Answers 20 of 20 questions

Metaphysics

Being and realityGod as being itself

What truly is, is the Necessary Existent, whose essence is nothing other than its existence; all else is possible in itself and exists only as necessitated by it, through a hierarchy of intellects emanating from it.

Stated in the textwājib al-wujūd, mumkin al-wujūd, māhiyya, wujūd, fayḍDraft — not yet reviewed

The Book of Healing Metaphysics VIII.4 · The Book of Healing Metaphysics I.6–7

The other half of the thesis is that in every possible being essence is distinct from existence (Metaphysics I.5; V.1). Whether he made existence an accident of essence is disputed: Averroes charged him with it, and Rahman (1958) and Bertolacci (2012) assess the charge.

UniversalsModerate realism

A nature such as horseness, taken in itself, is neither universal nor particular; it is particular in individual things and universal only as conceived by an intellect.

Scholarly consensusmāhiyya, kullī, al-iʿtibārāt al-thalāthaDraft — not yet reviewed

The Book of Healing Metaphysics V.1–2

Natures also exist before the many, as known by the separate intellects and the First, which the later Latin scheme of before, in and after things takes from him.

God and the fundamentalDemonstrable by reason

Reason proves the Necessary Existent from the bare fact that something exists: possible beings, singly or as a whole, need a cause outside them, which must be necessary in itself, one and simple.

Stated in the textwājib al-wujūd bi-dhātihi, burhān al-ṣiddīqīnDraft — not yet reviewed

The Book of Healing Metaphysics I.6–7 · The Book of Healing Metaphysics VIII.1–5 · Pointers and Reminders IV

Two proofs are involved: the Healing (Metaphysics VIII.1–3) shows that a chain of causes is finite, while the Pointers (IV) argue from the whole of possible beings, finite or infinite, and need no ban on infinite regress (Mayer, 2001).

Soul and bodySeparable soul

The rational soul is an incorporeal substance, since intellectual thought cannot reside in any bodily organ. A man created in the void, aware of no body, would still affirm his own self; Ibn Sina offers this as a pointer to the soul's otherness from the body, not as the proof.

Stated in the textnafs nāṭiqa, jawhar, al-insān al-ṭāʾir, tanbīhDraft — not yet reviewed

The Book of Healing Psychology V.2 · The Book of Healing Psychology I.1

The soul comes into being with its body and is individuated by it (Psychology V.3), so it is not pre-existent as in Plato. The force of the flying man is disputed (Marmura, 1986; Kaukua, 2015), and it meets the objection Arnauld pressed against Descartes: affirming one thing without affirming another does not show they are distinct (Fourth Objections, AT VII 201–203).

Death and immortalityThe soul is immortal

The rational soul does not perish with the body, because it does not depend on the body for its existence; each soul survives as an individual and is happy or miserable according to the perfection it reached.

Stated in the textmaʿād, saʿāda, shaqāwaDraft — not yet reviewed

The Book of Healing Psychology V.4 · The Book of Healing Metaphysics IX.7

In the Healing he accepts bodily resurrection on the authority of revealed law without demonstrating it (Metaphysics IX.7). Al-Ghazali charged the philosophers with denying it and counted that unbelief (Incoherence, Discussion 20).

The cosmosEternal but produced

The world has no first moment, yet it exists only because the First eternally necessitates it; to be caused does not require coming after nothing in time, only being posterior in essence.

Stated in the textibdāʿ, ḥudūth dhātī, qidamDraft — not yet reviewed

The Book of Healing Metaphysics VI.1–2 · The Book of Healing Metaphysics IX.1 · Pointers and Reminders V

Freedom and determinismFree and determined

Every event, human choices included, is necessary through its causes in an order that flows from the First; we choose, but our choice is itself caused by our dispositions and what we perceive, and providence includes it.

Another reading. Ibn Sina never poses the problem of responsibility under determinism, so calling him a compatibilist reads a later question into a theory of causal necessity and providence.

Contested readingikhtiyār, qadar, ʿināyaDraft — not yet reviewed

The Book of Healing Metaphysics I.6–7 · The Book of Healing Metaphysics IX.6

The necessitarian reading of his causal theory is argued by Belo, Chance and Determinism in Avicenna and Averroes (2007).

CausationCauses necessitate

Whatever is possible in itself is equally open to being and not being, so it exists only when a cause makes it necessary; the effect is necessary through its cause and needs that cause for as long as it exists, not only to begin. The chain ends in the Necessary Existent, which is necessary in itself. In metaphysics the efficient cause is the giver of existence, not only a mover, and the final cause is the cause of the other causes' being causes.

Stated in the textThe Healing (Metaphysics I.6–7, VI; Physics I); Pointers IVwājib al-wujūd bi-dhātihi, mumkin al-wujūd bi-dhātihi, wājib bi-ghayrihi, al-ʿilla al-tāmma, al-fāʿil, al-ghāya, ʿillat al-ʿilalDraft — not yet reviewed

The Book of Healing Metaphysics I.6–7 · The Book of Healing Metaphysics VI.1–2 · The Book of Healing Metaphysics VI.5 · The Book of Healing Physics I.13–14 · Pointers and Reminders IV

Chance exists only relative to a limited view; from the whole order of causes everything is necessary (Physics I.13–14). The necessitarian reading is argued in full by Belo (Chance and Determinism in Avicenna and Averroes, 2007). He keeps final causes, so `teleological` could be added; it is left off because his distinctive thesis is about existence and necessity.

Epistemology

Sources of knowledgeIllumination from a higher intellect

Perception, imagination and reflection prepare the soul, but the universal form is received from the Active Intellect, which emanates intelligibles onto a soul made ready for them, as the sun's light lets the eye see.

Another reading. Gutas ("The Empiricism of Avicenna", 2012): emanation is Ibn Sina's metaphysical description of what is, in cognitive terms, abstraction from sensory images by the human intellect, so the source is experience completed by intellect.

Another reading. Hasse ("Avicenna on Abstraction", 2001) and McGinnis (2007) reject the either/or: abstraction prepares the soul and emanation completes it, so both codes apply.

Contested readingal-ʿaql al-faʿʿāl, fayḍ, tajrīd, istiʿdādDraft — not yet reviewed

The Book of Healing Psychology V.5 · The Book of Healing Psychology II.2

The coding follows the emanation reading, on which the Active Intellect does the work (Davidson, 1992). The `illumination` option already allows that the senses prepare the mind first.

Certainty, doubt and the limits of knowledgeYes

Certain knowledge is attainable: the first notions (existent, thing, necessary) and the first principles are known in themselves, and demonstrations from them yield certainty; whoever denies the principle of contradiction has to be made to feel its force.

Scholarly consensusyaqīn, burhān, al-awwaliyyātDraft — not yet reviewed

The Book of Healing Metaphysics I.5 · The Book of Healing Metaphysics I.8

Innate knowledgeNo innate contents

The human intellect begins as pure potentiality, a material intellect with no forms of its own, and acquires intelligibles step by step; even the first principles come to it without learning but are not stored in it from birth.

Scholarly consensusal-ʿaql al-hayūlānī, al-ʿaql bi-l-malaka, al-maʿqūlāt al-ūlāDraft — not yet reviewed

The Book of Healing Psychology I.5 · The Book of Healing Metaphysics I.5

The primary notions (existent, thing, necessary) are said to be in the soul from the first and cannot be acquired from anything better known (Metaphysics I.5), which borders on innateness; but the intellect has them only once it is actualised, not from birth.

TruthCorrespondence · Truth as a feature of being

A statement is true when it corresponds to how the thing is, but "true" is said first of existence itself, and most of all of the Necessary Existent, whose existence is permanent.

Scholarly consensusḥaqq, ṣidq, wujūdDraft — not yet reviewed

The Book of Healing Metaphysics I.8 · The Book of Healing Metaphysics VIII.6

Epistemic justificationDemonstration from first principles

Certain knowledge comes by demonstration, and demonstration rests on premises of determinate kinds: primary propositions the intellect affirms by itself, observations, experiential propositions, and some others, each with its own warrant. Experience (tajriba) yields universal premises only when it is joined with a hidden syllogism showing that the regularity is not by chance. The middle terms of demonstration can be found by intuition (ḥads), a contact with the Active Intellect.

Scholarly consensusThe Book of Healing (Demonstration; Psychology); The Salvation (Logic)burhān, yaqīn, taṣdīq, awwaliyyāt, mujarrabāt, ḥadsDraft — not yet reviewed

The Book of Healing Demonstration I.9 · The Salvation Logic · The Book of Healing Psychology V.6

Intuition (ḥads) is a source of middle terms (Gutas, "Intuition and Thinking: The Evolving Structure of Avicenna's Epistemology", 2001), but what is grasped is still certified by its place in a demonstration, so `illumination` (coded for him under epi.source) is not added here. On experience in the Burhān, McGinnis ("Scientific Methodologies in Medieval Islam", 2003).

Axiology

The highest goodContemplation

The soul's perfection is to become an intellectual world mirroring the whole order of existence, joined to the Active Intellect; its pleasure, begun in this life, is complete after death.

Another reading. Pointers and Reminders describes happiness as love and joy in the First, reached through the stations of the knowers and perfect only after death, nearer to union with God.

Contested readingsaʿāda, kamāl, ittiṣāl, ladhdha ʿaqliyyaDraft — not yet reviewed

The Book of Healing Metaphysics IX.7 · Pointers and Reminders VIII–IX

The basis of moralityVirtue

Right action keeps to the mean set by practical wisdom, through temperance, courage and wisdom whose sum is justice; the prophet's law gives that mean to people who cannot reach it by reason.

Scholarly consensustawassuṭ, ʿadāla, ḥikma, sharīʿaDraft — not yet reviewed

The Book of Healing Metaphysics X.5 · The Book of Healing Metaphysics IX.7

Ethics is thin in his works; the role of revealed law has no option of its own.

Virtue and knowledgeKnowledge plus habituation

Theoretical knowledge alone does not perfect the soul: it must also acquire, by habit, a disposition of the mean that keeps it from being ruled by bodily inclinations.

Scholarly consensusmalaka, tawassuṭ, akhlāqDraft — not yet reviewed

The Book of Healing Metaphysics IX.7

The state and legitimacyRule by the wise

The best city is founded by a prophet who gives it law, and ruled after him by a successor distinguished by practical wisdom and knowledge of the law; justice is each class doing its work.

Scholarly consensusnabī, sunna, khalīfa, sharīʿaDraft — not yet reviewed

The Book of Healing Metaphysics X.2–5

The ruler is a prophet-lawgiver, as in al-Farabi, not a philosopher-king.

Beauty and artValuable imitation · Beauty as ascent

Poetry is imitative speech that moves the soul by imaginative assent rather than by demonstration, and is useful for that; beauty in its highest sense is the First's own perfection, which souls love and are drawn toward.

Scholarly consensustakhyīl, muḥākāt, jamāl, ʿishqDraft — not yet reviewed

The Book of Healing Poetics (Fann al-shiʿr) · The Book of Healing Metaphysics VIII.7 · Pointers and Reminders VIII · Treatise on Love whole work

Poetics belongs to logic for Ibn Sina, as the art of imaginative assent; no option names that.

JusticeJustice laid down by a prophet-lawgiver · Order of the soul

Human beings cannot live alone; their partnership needs exchange, and exchange needs a law (sunna) and justice. These cannot be left to people, each of whom judges just what is to his own advantage, so they must be laid down by a human lawgiver whom God distinguishes, the prophet. In the soul, temperance, courage and practical wisdom are the chief virtues, and their sum is justice.

Scholarly consensusʿadl, ʿadāla, sunna, sharīʿa, mushāraka, muʿāmala, nabīDraft — not yet reviewed

The Book of Healing Metaphysics X.2 · The Book of Healing Metaphysics X.5 · Pointers and Reminders Logic, Sixth Method

In logic Ibn Sina counts "justice is good" among widely accepted premises, not first truths of reason, which fits his grounding of justice in law rather than in a justice reason knows by nature.

The nature of valueGood convertible with being

Good is what each thing desires, which is existence and the perfection of existence; evil has no essence and is a lack of existence or of a perfection. The Necessary Existent, whose existence lacks nothing, is pure good. Moral judgments such as "justice is fine" are not first principles of reason but widely accepted, praised opinions held from upbringing and common life; someone raised alone would not find them evident.

Scholarly consensuskhayr maḥḍ, wājib al-wujūd, kamāl, sharr, ʿadam, mashhūrāt, ārāʾ maḥmūdaDraft — not yet reviewed

The Book of Healing Metaphysics VIII.6 · The Book of Healing Metaphysics IX.6 · Pointers and Reminders Logic, Sixth Method

Two levels: goodness as existence and perfection holds whatever anyone judges, while the common moral appraisals of praise and blame rest on general acceptance, not demonstration. The stance codes the first; the second is the main reason this coding should be reviewed.

contested reading · open a row for the explanation and its sources

Method روش و شیوه اندیشه‌ورزی فلسفی

Ibn Sina builds philosophy as a demonstrative system: each science has its own subject and principles, and its conclusions follow by syllogism from what is self-evident or already proven. He restates the Aristotelian sciences in his own order, uses thought experiments as "pointers" for an attentive mind, and in the late Pointers and Reminders compresses the whole system into terse hints.

Posing questions

Ibn Sina places each question in the science it belongs to and first fixes that science's subject: metaphysics studies the existent as existent, and God is something it seeks to prove, not its subject. He starts from the first notions, existent, thing and necessary, which cannot be defined without circularity and can only be called to mind. A question is then settled by finding the middle term that joins its subject and predicate.

The Book of Healing Metaphysics I.1–2 · The Book of Healing Metaphysics I.5 · The Book of Healing Demonstration (al-Burhān)

Arguing and justifying

His standard of proof is demonstration (burhān): a syllogism from true, primary and necessary premises that gives the cause of its conclusion, as set out in the logic of the Shifāʾ. In metaphysics he prefers proofs that rest on the analysis of existence itself, necessary or possible in itself, rather than on motion or the created world, and he says so of his proof of the Necessary Existent in the Ishārāt. The flying man is a different tool: a thought experiment that asks the reader to imagine a person created in mid-air, cut off from all sensation, and to notice that he would still affirm his own existence.

The Book of Healing Demonstration (al-Burhān) · Pointers and Reminders IV · The Book of Healing Metaphysics I.6–7 · The Book of Healing Psychology I.1 · Pointers and Reminders III.1

Criticising rival views

Rival views are restated and then tested by the same logic. The Shifāʾ refutes the Platonists' separate Forms and mathematical objects, and rejects the view he ascribes to Porphyry that the intellect becomes one with what it knows. Against the theologians who say that a thing, once made, no longer needs its maker, he argues that an effect depends on its cause for as long as it exists. He judges the Peripatetics too, claiming to keep what is sound in them and to add what his own reflection found.

The Book of Healing Metaphysics VII.2–3 · The Book of Healing Psychology V.6 · Pointers and Reminders VII · The Book of Healing Metaphysics VI.1–2 · The Book of Healing Prologue

Reason, experience and other ways of knowing

The intellect ranks highest, and logic is its instrument against error. The senses give particulars from which the intellect abstracts universals, but knowledge itself comes when the soul is joined to the Active Intellect. He also credits intuition (ḥads), the power to hit on a middle term without being taught, which at its height is the holy intellect of a prophet. The last chapters of the Ishārāt describe the states and stations of the knowers (ʿārifūn) in their own terms, as a summit of the same path rather than a rival to it.

Pointers and Reminders Logic · The Book of Healing Psychology V.5 · The Book of Healing Psychology V.6 · Pointers and Reminders VIII–IX

Language and style

The Shifāʾ is an encyclopedia that restates the sciences in its own order (logic, natural philosophy, mathematics, metaphysics) in expository Arabic prose, not as line-by-line commentary; the Najāt abridges it. The Ishārāt is deliberately compressed: short chapters headed "pointer", "reminder" or "delusion and alert" leave the reader to complete the argument, and the book closes by asking that it be kept from those unready for it. He also wrote a philosophical compendium in Persian, the Dānishnāma-yi ʿAlāʾī, and symbolic treatises such as the Treatise on Love.

The Book of Healing Prologue · The Salvation whole work · Pointers and Reminders X · Treatise on Love whole work

Across the works

The Book of Healing, The SalvationThe Shifāʾ (c. 1020–1027) follows the order and demonstrative ideal of the Peripatetics; its prologue says so and refers readers who want his views without concession to the school to another book, the Eastern Philosophy. The Najāt is a shorter compendium drawn largely from it.The Book of Healing Prologue
Pointers and RemindersThe Ishārāt, a late work, recasts the system as compressed hints, puts the argument from existence at the head of its metaphysics, and ends with chapters on happiness and the stations of the knowers, read philosophically.Pointers and Reminders IV · Pointers and Reminders VIII–IX
Treatise on Love, AutobiographyShorter works use other forms. The Treatise on Love treats love as a force running through all beings in a Neoplatonic idiom; the Autobiography tells how he learned logic and metaphysics largely on his own, praying when he could not find a middle term.Treatise on Love whole work · Autobiography whole work

burhān, qiyās, al-ḥadd al-awsaṭ, mawḍūʿ, ḥads, ishāra, tanbīh

Arguments

The flying manThe reader is alerted that the self whose existence he affirms is other than the body and its parts, and is aware of itself directly. Ibn Sina offers this as a pointer (tanbīh) for one able to attend, not as a demonstration; that the soul is a substance in its own right is proved elsewhere (Psychology V.2).

1Imagine a man created all at once and fully formed, suspended in empty air, his sight veiled, his limbs held apart so that they do not touch, feeling nothing outside or inside his body.
2Such a man would still affirm that he himself exists.
3He would not affirm the existence of any limb, organ or body, and would not even conceive of one.
4What is affirmed is not the same as what, in the same state, is not affirmed.
∴The reader is alerted that the self whose existence he affirms is other than the body and its parts, and is aware of itself directly. Ibn Sina offers this as a pointer (tanbīh) for one able to attend, not as a demonstration; that the soul is a substance in its own right is proved elsewhere (Psychology V.2).

Thomas Aquinas objects. (Reconstruction; Aquinas does not discuss the flying man.) The soul does not know itself actually through its essence but through its acts, which in this life begin from the senses; a soul cut off from all sensation would have no actual self-awareness, though it would keep the habitual self-knowledge that comes from its presence to itself.

David Hume objects. (Applied; Hume does not discuss Ibn Sina.) A mind stripped of every perception would not be aware of a self but would be nothing at all; there is no impression of a self over and above particular perceptions.

thought-experiment · The Book of Healing Psychology I.1 · The Book of Healing Psychology V.7 · Pointers and Reminders III.1

Draft — not yet reviewed

The proof of the Necessary ExistentThere is a being necessary in itself, which on further argument is one, simple and without any essence besides its existence: the First.

1Something exists.
2Whatever exists is either necessary in itself or possible in itself.
3What is possible in itself is equally open to existing and not existing, so if it exists it needs a cause outside itself that makes it exist.
4Take all possible existents together, finite or infinite in number; the whole is itself possible, since it depends on its members, and so needs a cause. (This is the Pointers proof, which needs no ban on infinite regress.)
5That cause cannot be inside the whole, since it would then cause itself, nor a possible existent, since it would belong to the whole; so it is outside it and necessary in itself.
∴There is a being necessary in itself, which on further argument is one, simple and without any essence besides its existence: the First.

David Hume objects. (Applied; Hume does not discuss Ibn Sina.) In his own voice: the non-existence of any being is as clear and distinct an idea as its existence, so no being's existence can be demonstrated (EHU XII, Part 3). In the Dialogues (IX), Cleanthes adds that whatever we conceive as existent we can conceive as non-existent, and that a whole chain needs no cause once each member is explained, the whole being only an act of the mind.

Immanuel Kant objects. (Applied; Kant does not discuss Ibn Sina.) The principle that the contingent has a cause has meaning and use only within the world of experience, so it cannot carry us to a necessary being beyond it.

deductive · Pointers and Reminders IV · The Book of Healing Metaphysics I.6–7 · The Book of Healing Metaphysics VIII.4

Draft — not yet reviewed

Key terms

All key terms →

وجود / ماهيةwujūd / māhiyya: existence · essence · quiddityWhat a thing is differs from that it is: one can grasp what a triangle is without knowing whether any exists. In everything but the necessary existent, existence comes to the essence from a cause.3 links to other thinkers →
واجب الوجودwājib al-wujūd: the necessary existentA being that exists of itself, as against possible beings (mumkin al-wujūd), which need a cause to exist. Even taken as a whole, a chain of possible beings needs a cause outside it: one necessary existent, wholly simple.3 links to other thinkers →
العقل الفعّالal-ʿaql al-faʿʿāl: the active intellect · agent intellectA separate intellect, the last of the celestial intelligences, which gives forms to matter and intelligibles to minds prepared to receive them. Human understanding is the soul's contact with it.3 links to other thinkers →
النفس الناطقةal-nafs al-nāṭiqa: the rational soulThe human soul is an immaterial substance that uses the body but does not depend on it. A person created in mid-air, with no sensation of his body, would still affirm that he exists.7 links to other thinkers →
الكلّيal-kullī: the universalA nature such as horseness is in itself neither universal nor particular. It is particular as it exists in things, and universal only as the mind takes it as said of many.
السعادةal-saʿāda: happiness · felicityThe soul's true perfection: to become an intellectual world that mirrors the order of all things, and after death the pleasure of that perfection, beside which bodily pleasure is faint.1 link to other thinkers →