Islamic Philosophy: Falsafa, Kalām, Key Thinkers and Great Debates

Islamic philosophy is the tradition of philosophical argument that grew up in the Islamic world from the eighth and ninth centuries onwards, written mostly in Arabic and later also in Persian. It includes falsafa, which continued Greek philosophy; kalām, rational theology; Sufi metaphysics; and later syntheses such as Illuminationism and Mulla Sadra’s transcendent philosophy.

Its thinkers asked whether the world had a beginning, whether anything except God really causes anything, whether we author our own acts, and whether reason can know right from wrong without revelation. Their answers shaped Jewish and Latin Christian thought and are still argued over.

What does Islamic philosophy cover?

Some scholars prefer “philosophy in the Islamic world” or “Arabic philosophy”, because not everyone in the story was Muslim: many translators were Christians, and Jewish thinkers such as Saadia Gaon wrote philosophy in Arabic (see Jewish philosophy). Four strands are usually counted.

• Falsafa, from the Greek philosophia. The falāsifa worked in the line of Aristotle and the Neoplatonists, aiming at demonstration from premises any rational person should accept. Al-Kindi, Al-Farabi, Ibn Sina and Ibn Rushd are its best-known names.
• Kalām, literally “speech” or “discussion”. The mutakallimūn defended the doctrines of faith by argument, building theories of atoms, causation and the divine attributes along the way. The Muʿtazila gave reason a strong role in knowing God’s justice; the Ashʿarīs stressed God’s unlimited power; the Māturīdīs took a middle course.
• Sufi metaphysics. Sufism is a path of devotion and practice, but Ibn Arabi built from it a theory of being: true existence (wujūd) belongs to God alone, and the cosmos is a continual divine self-disclosure. Later followers called this the “unity of being” (waḥdat al-wujūd).
• Later syntheses. Suhrawardi’s Illuminationism, built on knowledge by presence and a hierarchy of lights, and the school of Isfahan, culminating in Mulla Sadra’s transcendent philosophy, wove the strands together.

Where does philosophy end and theology begin? The camps were often rivals: philosophers charged kalām with arguing from unproved premises; theologians charged the philosophers with letting Aristotle overrule revelation. Historians today count both as philosophy wherever they argue about causes, time, freedom or knowledge, noting that kalām starts from commitments of faith and falsafa claims not to. Sufi claims rest partly on mystical experience, and enter philosophy where they are argued for.

The translation movement: from Greek to Arabic, and on to Latin

From the mid-eighth to the tenth century, under the Abbasid caliphs in Baghdad, a large part of Greek science and philosophy was translated into Arabic, often by way of Syriac: Aristotle, Neoplatonic writings, Galen, Euclid, Ptolemy and Plato in summaries. The translators were mostly Syriac-speaking Christians, the best known being Ḥunayn ibn Isḥāq. The work is often linked with the “House of Wisdom” in Baghdad, though historians debate how far that was a formal institution.

One text coloured much of what followed. A paraphrase of parts of Plotinus circulated as the Theology of Aristotle, so Arabic readers met an Aristotle blended with Neoplatonism. The falāsifa’s picture of a necessary First Cause from which the world emanates in ordered levels owes much to that blend.

In the twelfth and thirteenth centuries the flow reversed. Arabic works were translated into Latin and Hebrew: Ibn Sina’s distinction between essence and existence passed into Thomas Aquinas, and Ibn Rushd became “the Commentator” for Latin readers. Maimonides wrote his Guide for the Perplexed in Arabic, in conversation with falsafa and kalām. See medieval Christian philosophy and Eastern and Western philosophy.

The great debates of Islamic philosophy

Islamic thinkers appear on over sixty of the 131 cards of The Coordinates, drawn from The Coordinates of Thought. Seven debates show the range.

Did the world have a beginning?

On the origins card, Al-Kindi argues that an actual infinite cannot exist, so the past is finite and the world began. Al-Farabi and Ibn Sina held instead that the world proceeds eternally from a necessary First Cause: caused and dependent, but without a first moment. Al-Ghazali argued that they had proved no such thing, and that God’s eternal will created the world with a beginning; Ibn Rushd answered for the philosophers. The argument from a finite past survives as the kalām version of the cosmological argument on the natural theology card.

Does fire burn cotton? Causation and occasionalism

In The Incoherence of the Philosophers, Al-Ghazali argued that we see fire touch cotton and the cotton burn, but never see the fire produce the burning. The link is habitual, not demonstrably necessary: God creates the burning when the contact occurs, and could do otherwise. This view, occasionalism, was widely held among Ashʿarī theologians, though Al-Ghazali also sketched a second account in which created causes act, but only as God wills. Ibn Rushd replied in The Incoherence of the Incoherence that to deny real causes is to deny that things have natures, and so to deny knowledge. Readers often set him beside David Hume on the causation card, though Hume drew no theological conclusion.

Figure	Dates	Tradition	Contribution
Aristotle	384–322 BCE	Greek	Four causes: material, formal, efficient, final
Nagarjuna	c. 150–250 CE	Indian Buddhist	Dependent origination; critique of self-existent causes
Al-Ghazali	1058–1111	Islamic	Denied necessary connection; occasionalist conclusion
Ibn Rushd	1126–1198	Islamic	Defended real causal powers against Al-Ghazali
David Hume	1711–1776	European modern	Constant conjunction; necessity as a habit of mind
Elizabeth Anscombe	1919–2001	Analytic	Causation is observable; Hume's argument overreaches

Do we choose our acts? Free will and kasb

The Muʿtazila held that human beings bring about their own acts; otherwise divine reward and punishment would be unjust. Al-Ash’ari held that God creates all things, human acts included, while the agent “acquires” (kasb) the act and answers for it. Critics ask whether acquisition adds anything to the claim that God does everything; defenders reply that it separates a chosen act from a tremor. The Māturīdī school gave human choice a firmer place. The free will card is marked △, as still contested.

What a thing is, and that it is: essence and existence

Ibn Sina drew a distinction that later metaphysics in Arabic, Persian and Latin built on. You can know what a horse is without knowing whether any exists, so existence is not part of what a horse is. Whatever has an essence that does not include existence needs a cause to exist; following that chain, Ibn Sina argued for a Necessary Existent whose essence is simply its existence. His “floating man”, created in mid-air and cut off from every sensation, would still be aware of himself — a sign, he argued, that the self is known apart from the body. Suhrawardi is usually read as treating existence as a concept the mind adds; Mulla Sadra reversed this, holding that existence is what is real and comes in degrees. See Ontology and Substance theory.

Reason and revelation

Al-Farabi held that religion conveys in images and symbols what philosophy demonstrates, for people who cannot follow demonstration. Ibn Rushd’s Decisive Treatise argued that the religious law itself calls for philosophical study, that demonstrated truth cannot conflict with revealed truth, and that where scripture’s apparent sense clashes with demonstration, the qualified should read it allegorically. Al-Ghazali accepted logic but held that reason alone cannot settle some questions; his Deliverance from Error tells how doubt led him to Sufism. Ibn Tufayl’s Hayy ibn Yaqzan imagines a child raised alone on an island who reasons his way to the truths that revelation teaches others.

Is something good because God commands it?

The Muʿtazila held that justice is good and lying bad in themselves, and that reason can know this; God commands what is good because it is good. The Ashʿarīs answered that moral status depends on God’s command, so that apart from revelation nothing is obligatory. Al-Māturīdī held that reason can recognise some goods and evils, with revelation completing them. It is the Euthyphro question, set out on the divine command card. Miskawayh, meanwhile, built a Greek-inspired ethics of character, with justice as the harmony of wisdom, courage and temperance.

Law and its purposes

Legal theory, uṣūl al-fiqh, asks how law is derived from its sources. Al-Shafi’i named four: the Qur’an, the prophetic sunna, consensus and analogy. Al-Shatibi argued that the law as a whole aims at human welfare, protecting religion, life, intellect, lineage and property, and that its rulings should be read through these purposes (maqāṣid). The philosophy of law card sets uṣūl al-fiqh beside natural law and legal positivism as one account of how law, morality and authority relate. See also Islamic jurisprudence.

Key Islamic philosophers, from Al-Kindi to Iqbal

• Al-Kindi (c. 800–870), “the philosopher of the Arabs”, urged that truth be accepted from whatever source it comes, even from earlier peoples.
• Al-Farabi (c. 870–950), “the Second Teacher” after Aristotle, described a virtuous city ruled by one who unites philosophy and prophecy.
• Ibn Sina (980–1037), Avicenna in Latin, is named on fifteen cards, more than any other Islamic thinker.
• Al-Ghazali (c. 1058–1111) criticised falsafa with its own logic; he appears on twelve cards, from causation to meaning in life.
• Ibn Rushd (1126–1198), Averroes, a judge in al-Andalus, commented on nearly all of Aristotle.
• Ibn Khaldun (1332–1406) proposed a science of society, with group solidarity (ʿaṣabiyya) driving the rise and fall of dynasties; see Philosophy of history.
• Mulla Sadra (c. 1571–1640) added substantial motion, change within the very substance of things, to the primacy of existence.
• Muhammad Iqbal (1877–1938) treated the self (khudi) as something to be strengthened, and ijtihād, independent reasoning, as the principle of movement in Islam.

The Islamic thinkers most cited across the cards, linked to their profiles (see also Islamic philosophy on the site):

The site files several thinkers who wrote in Persian or worked in Iran under Persian philosophy, among them Suhrawardi, Rumi, al-Ṭūsī and Mulla Sadra:

A short history of Islamic philosophy: timeline

Period	What happened	Key figures
c. 750–950	Translation movement in Baghdad; first falsafa and kalām; foundations of legal theory	Al-Shafi’i, Al-Kindi, Al-Jahiz, Al-Ash’ari, al-Māturīdī, Al-Farabi
c. 950–1110	The classical synthesis and its critics	Miskawayh, Ibn al-Haytham, Al-Biruni, Ibn Sina, Ibn Hazm, Al-Ghazali
c. 1110–1200	Philosophy in al-Andalus; Illuminationism; kalām absorbs Ibn Sina	Ibn Bajja, Ibn Tufayl, Ibn Rushd, Suhrawardi, Fakhr al-Din al-Razi
c. 1200–1400	Sufi metaphysics; Avicennan revival; purposes of law; a science of society	Ibn Arabi, Rumi, Naṣīr al-Dīn al-Ṭūsī, Al-Shatibi, Ibn Khaldun
c. 1500–1800	The school of Isfahan under the Safavids; philosophy and kalām in Ottoman and Mughal lands	Mulla Sadra, Shah Waliullah
1850–today	Reform, revival and dialogue with European thought	Muhammad Iqbal, Seyyed Hossein Nasr

For every tradition side by side, see the philosophy timeline.

Did Islamic philosophy end with Ibn Rushd?

An older Western account ended the story with Ibn Rushd’s death in 1198, as if Al-Ghazali’s attack had closed the subject. That picture reflected what had reached Latin, not what happened; recent scholarship treats the centuries after 1200 as among the most productive.

• Kalām absorbed falsafa. Fakhr al-Din al-Razi examined Ibn Sina’s arguments premise by premise; Naṣīr al-Dīn al-Ṭūsī defended them; later theologians wrote in Ibn Sina’s vocabulary.
• The school of Isfahan. Under the Safavids, Mir Damad and his student Mulla Sadra joined Avicennan philosophy, Illuminationism and Ibn Arabi’s metaphysics; Sadra is still taught in Iran.
• South Asia and the Ottoman lands. Logic, philosophy and kalām were taught in madrasas from Istanbul to Delhi.
• Modern thought. Iqbal’s The Reconstruction of Religious Thought in Islam read the tradition alongside Bergson and modern physics; Seyyed Hossein Nasr traced the ecological crisis to a loss of the sacred view of nature.

How to start reading Islamic philosophy

1. Start with a debate, not a list of names. Read the causation card, Al-Ghazali’s fire and cotton, and Ibn Rushd’s reply.
2. Read two short primary texts. Deliverance from Error is an intellectual autobiography; Hayy ibn Yaqzan is a philosophical story. Both suit beginners.
3. Read a history. Peter Adamson’s Philosophy in the Islamic World follows the whole story, later centuries included.
4. Then try a classic. Ibn Sina’s Remarks and Admonitions, the opening of Ibn Khaldun’s Muqaddimah, or Ibn Arabi’s Ringstones of Wisdom with a guide.
5. Join a conversation. Browse Islamic philosophy and Religion & the Sacred, or ask a question.

The liveliest conversations in Islamic philosophy on the site:

Where do you stand?

Every question here has serious answers on more than one side. Pick a card, read the rival answers, then say which you find strongest and why. Members ask, reply and take sides; reading is free for everyone.

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