On the Heavens

The latter are composed of one or all of the four classical elements (earth, water, air, fire) and are perishable; but the matter of which the heavens are made is imperishable aether, so they are not subject to generation and corruption.

Averroes in particular wrote extensively about De Caelo, trying for some time to reconcile the various themes of Aristotelian philosophy, such as natural movement of the elements and the concept of planetary spheres centered on the Earth, with the mathematics of Ptolemy.

[8] These ideas would remain central to philosophical thought in the Islamic world well into the pre-modern period, and its influences can be found in both the theological and mystical tradition, including in the writings of al-Ghazali and Fakhr al-Din al-Razi.

European philosophers had a similarly complex relationship with De Caelo, attempting to reconcile church doctrine with the mathematics of Ptolemy and the structure of Aristotle.

The 14th-century French philosopher Nicole Oresme translated and commented on De Caelo in his role as adviser to King Charles V of France, on two occasions, once early on in life, and again near the end of it.

Some speculate that, having already had Oresme translate Aristotelian works on ethics and politics in the hope of educating his courtiers, doing the same with De Caelo may be of some value to the king.