  Al-Kindi sets out his cosmological theories in two further texts found in the same manuscript, On the Proximate Agent Cause of Generation and Corruption and On the Prostration of the Outermost Sphere. Also relevant here are numerous works on meteorology and weather forecasting. These apply the same cosmological ideas to show how heavenly motion produces rain and other meteorological phenomena in the lower world where we live. While these works are influenced by Aristotle, al-Kindi also draws on other Greek sources, such as Ptolemy. His knowledge of the Greek scientific tradition was in fact extensive. For instance, he uses Euclid and ideas that can be traced to Ptolemy in a well-known work on optics, On Perspectives, which is preserved only in Latin. Al-Kindi’s extant scientific corpus is sizable and includes treatises on the manufacture of drugs, music, astrology, and mathematics (see further Rosenthal 1942). But the focus here will be on al-Kindi’s philosophical views.