Al-Fārābī was a key figure in establishing much of the problematic of Islamic philosophy in the peripatetic tradition. He built on the earlier attempt by Abū-Yūsuf Yaʿqūb ibn Isḥāq al-Kindī to establish a technical language of philosophy in Arabic and presented a vocabulary and a curriculum that came to dominate for many centuries after his death. Al-Fārābī's epistemology and political philosophy were particularly influential. Firmly neoplatonic in tone, he differentiated between diverse kinds of intellect to describe human thought and gave an interesting and influential account of how knowledge can be analyzed in terms of a range of degrees of abstraction. The active intellect became a controversial topic in Islamic philosophy; it represented the highest one could go in one's thoughts and was responsible...