 Both treatises put human beings and their societies in an Aristotelian cosmological context, which Fârâbî describes in some detail. Humans and other kinds of animals, and also plants, are composites of some kind of soul (including, for humans, a rational soul) with a body composed out of the four sublunar elements, earth and water and air and fire; the whole sublunar world is governed, ultimately by God, but proximately by a series of nested heavenly spheres (each moved by an incorporeal intelligence) and by the “active intelligence” which is a source both of intellectual cognition to the human rational soul and of intelligible order to the sublunar world. But in what follows I will discuss only the strictly metaphysical parts of these texts, not the cosmology or the theories of the human soul, prophecy, or society. I will mainly follow the Perfect City, while noting some interesting differences in the Political Regime. The Political Regime in general seems more interested in classification and comparison. The human soul is introduced by being compared to various higher and lower things, and the way it achieves its intended perfection is compared to the ways they do. Likewise, God is introduced, in the prologue to the Political Regime, on a list of six kinds of incorporeal “principles” of physical things, and his causality is compared with the modes of causality of these other  principles.[45]