Kalam (Arabic: ‘speech’ or ‘word’) is Islamic scholastic theology — the discipline of using rational argumentation to defend and systematize Islamic doctrine against philosophical objections. Kalam emerged in the 8th century partly in response to contact with Greek philosophy (through the massive translation movement of the Abbasid era) and partly from internal disputes about divine attributes, free will, and the status of sinners. The Mutazilites are the first major school of kalam. The Ashari and Maturidi schools are the mainstream Sunni response. Major themes: proving God’s existence and unity (against atheism and polytheism); the divine attributes (are they real? identical with God’s essence?); the created or uncreated nature of the Quran; divine predestination and human free will; the intermediate position of the grave sinner. The great synthesis of kalam and Sufi spirituality is achieved by al-Ghazali (1058–1111 AD) in his Incoherence of the Philosophers and the Revival of the Religious Sciences.