The Islamic world · 8th c. – present
Kalām (Muʿtazila & Ashʿarism)
Faith must be defended by rational argument; the Muʿtazila made God’s justice and unity the measure, while the Ashʿarites made God’s unlimited power and will the measure.
Is something good because God commands it, or does God command it because it is good?
Early Islamic disputes after the civil wars, over free will, the status of grave sinners and God’s attributes, met the arguments of Christian, Jewish and Manichaean debaters. Muslims developed a dialectical theology to answer them; the Abbasid inquisition (833–848) briefly made Muʿtazili doctrine state policy.
The Muʿtazila argued that a just God cannot punish acts humans do not freely choose, and that reason can know good and evil. Al-Ashʿari replied that nothing limits God: God creates every event at each instant, so causes are only God’s habits, and good is whatever God commands.
- Muʿtazila: reason can know good and evil without revelation.
- Ashʿarites: God directly creates every event; causes are only habits.
- The world was created in time, out of nothing.
Ashʿarism, alongside Māturīdism, became the main theology of Sunni Islam, and Muʿtazili ideas lived on in Shiʿi and Jewish thought; its occasionalism anticipated later European debates on causation.
Thinkers
c. 874–936Abū al-Ḥasan al-AshʿarīMuʿtazili theologian who broke with his school around 912c. 1058–1111Al-GhazālīAshʿarite theologian who left his Baghdad chair for SufismKey texts
Where it came from
Borrowed fromAtomismKalām’s world of indivisible atoms re-created by God at every instant echoes Greek atomism, though how the idea travelled is debated.Reacted against
Falsafa (Arabic Aristotelianism)Al-Ghazālī’s Incoherence of the Philosophers attacked Avicenna’s eternal world and necessary causation, while later kalām absorbed philosophical logic.
What it led to
Borrowed byMedieval Jewish philosophySaadia built his proofs of creation and divine unity with the methods of Muʿtazili kalām.Borrowed by
Sufi metaphysicsAl-Ghazālī, a leading Ashʿarite, made Sufi practice respectable within Sunni orthodoxy, joining theology to experiential knowledge.
Its answers to the big questions
God & the ultimateIs there a ground of everything?The world began to exist, so it has a cause: a God who freely chose to create.On the record
Kalām is dated from the 8th century, with Wāṣil ibn ʿAṭāʾ (d. 748).
This is a convention. Sunni sources trace the Muʿtazila to Wāṣil’s withdrawal from the circle of al-Ḥasan al-Baṣrī in Basra over the status of the grave sinner, but the story of the name is told rather than documented, and the Encyclopaedia of Islam explains the name differently. Arguments about free will and the sinner (the Qadariyya and Murjiʾa) already ran in the late 7th century, so the start date marks when kalām became a recognisable school, not its first debates.
Sources: Wikipedia, “Muʿtazilism” (citing the Encyclopaedia of Islam)
Kalām atomism echoes Greek atomism.
Maimonides already traced kalām atomism to the Greeks; 19th-century scholars proposed Indian sources instead. Shlomo Pines found real resemblances but judged the question of origin unresolved, and Alnoor Dhanani compared kalām atoms to Epicurean minimal parts without identifying a route of transmission. Kalām built its arguments from paradoxes of the infinite, in its own way; the link is drawn as a resemblance whose path is unknown, which the note states.
Sources: Stanford Encyclopedia of Philosophy, “Arabic and Islamic Natural Philosophy and Natural Science” · Iqbal Review (1991), on the sources of kalām atomism