Muslim philosophers both profess Islam and engage in a style of philosophy situated within the structure of Islamic culture, though not necessarily concerned with religious issues. The sayings of the companions of Muhammad contained little philosophical discussion. In the eighth century, extensive contact with philosophical cultures of the West led to a drive to translate philosophical works of these cultures (especially the texts of Aristotle) into Arabic.
The ninth-century Neo-Platonist Al-Kindi is considered the founder of Arab philosophy. The tenth century philosopher al-Farabi contributed significantly to the introduction of Greek and Roman philosophical works into Muslim philosophical discourse and established many of the themes that would occupy Islamic philosophy for the next centuries; in his broad-ranging work, his work on logic stands out particularly. In the eleventh century, Avicenna, one of the greatest creative philosophers ever, developed his school of philosophy with strong Aristotelian and Neoplatonist roots. In the twelfth century, the philosophy of illumination was systematized by Shahab al-Din Suhrawardi. Towards the end of the century philosophy underwent a decline in much of the Muslim world, in part due to al-Ghazali's argument that philosophy was incompatible with religion. In Andalusia, Averroes, defended philosophy against this charge; his extensive works include noteworthy commentaries on Aristotle. Although philosophy in its traditional Aristotelian form fell out of favor in much of the Arab world, forms of mystical philosophy following on from writers such as Ibn Arabi and Ibn Sabin, persisted.
After Averroes, a vivid philosophical activity persisted in the eastern Muslim world – especially Persia through works of Shiite philosophers such as Nasir al-Din al-Tusi, Mir Damad, and Mulla Sadra. Tabatabai suggests that the "element that was instrumental in the appearance of philosophical and metaphysical thought in Shi’ism and through Shi’ism in other Islamic circles was the treasury of knowledge left behind by the Imams." Ali's Nahj al-Balagha is also considered as a primary source of the doctrines professed by Shiite thinkers such as Mir Damad, Mulla Sadra, their pupils and their pupils' pupils: Ahmad al-Alawi, Mohsen Fayz Kashani, Abd al-Razzaq Lahiji, Qazi Sa’id Qumi, etc.