Metaphysics(Ibnu Rushd)

Metaphysics, for Ibn Rushd, does not simply deal with God or theology; rather it concerns itself with different classes of being and the analogical idea of being. It is, thus, a science that distinguishes inferior classes of being from real being. Ibn Rushd, the adamant Aristotelian, puts his own slant on Aristotle's metaphysics.

Ibn Rushd’s classification of being begins with accidental substances, which are physical beings, then moves to being of the soul / mind and finally discusses whether the substance existing outside the soul, such as the sphere of the fixed stars, is material or immaterial. This hierarchy, notes Charles Genequand, differs from Aristotle's hierarchy of material beings, beings of the soul / mind and unchangeable entities. The first and third categories of both thinkers are somewhat similar in that they encompass a straight demarcation between material and immaterial being. Ibn Rushd’s second class of being, however, includes both universals and mathematical beings; and as such cannot be the bridge between physics and metaphysics as it is in Aristotle. Rather, he contended that all autonomous beings, whether material or not, constitute a single category. This was likely a response to the more materialistic interpretations of Aristotle, such as that of Alexander of Aphrodisias, for Ibn Rushd did not see physics and the metaphysical at opposite sides of the spectrum.

Substance, not beings of the mind, was the common link between physics and metaphysics for Ibn Rushd. Substance, therefore, has an ontological, though not necessarily temporal, priority over other parts of being. Since, then, metaphysics covers both sensible and eternal substances, its subject matter overlaps with that of physics. In the cosmos, then, there are two classes of eternal things, the essentially eternal and the numerically eternal. This division represents the separation between the celestial realm and the physical universe, where the living beings in the latter are bound to an eternal cycle of generation and corruption, while the former are immortal animals. Ibn Rushd does not contend that celestial bodies cause the world, rather the motion of these bodies are the "principle" of what occurs on earth.

This point is more fully developed in Ibn Rushd's discussion regarding spontaneous generation: the idea that certain beings are created by external agents without being subject to the cycle of generation and corruption. This was a common subject of debate throughout later Greek and medieval philosophy. If beings like insects spontaneously generated from rotting food are externally generated, therein lies proof for a created universe and Asharite occasionalism, neither of which Ibn Rushd maintains. His solution is the Aristotelian doctrine of emanation, which states that no being is created but merely is the principle that unites matter and form. Since Ibn Rushd asserts that physical generation is the product of both seed, which contains forms in potentiality, and solar heat, the sun being a heavenly being; spontaneous generation, in which the seed is absent, is merely the effect of solar heat upon the basic elements (i.e. earth and water).

In the cosmological sphere, according to physics, one finds things that are both moving and moved at once and things that are only moved. Therefore, there must be something that imparts motion but is never moved; this is the Prime Mover (i.e. God). Physics, thus, provides the proof for the existence of a prime mover and metaphysics is concerned with the action of this mover. The Prime Mover is the ultimate agent for Ibn Rushd and it must be eternal and pure actuality. It did not merely push the universe into existence and remain idle thereafter, for the universe would slip into chaos. Ibn Rushd acknowledges that the idea of actuality being essentially prior to potentiality counters common sense, but to accept the opposite would entail the possibility of spontaneous movement or negation of movement within the universe.

How, then, is the prime mover the principle of motion and causation in the cosmos without being moved itself? Ibn Rushd contends that the prime mover moves the cosmos, particularly the celestial bodies, by being the object of desire. Celestial beings have souls, which possess the higher power of intellect and desire, and these beings desire the perfection of God, thereby they move accordingly. Desire in the celestial beings, according to Ibn Rushd, is not the real faculty it is in humans. Since these beings have no sense perception, desire is united with intellect causing a desire for what rationally is perfection - the Prime Mover.

Ibn Rushd rejects the Arab Neoplatonic doctrine of emanation because it simply implies a temporal succession of one being producing another, which is impossible for eternal beings. By this rejection, however, Ibn Rushd recognizes a problem within his system. If God is intellectually present within the celestial bodies, there is no need for them to move in an effort to acquire this perfection. Ibn Rushd responds with an analogy of a cabinet-maker, who has the idea of a cabinet existing in his mind, but his body needs to move in order to imprint this idea upon matter. Celestial beings move in likewise matter, in order to obtain perfection, which produces the physical universe. Furthermore, this effort to obtain perfection in the celestial bodies, which is in imitation of God, effects the order of the universe.

With the Prime Mover, the celestial bodies and the physical world, Ibn Rushd has a three level cosmological view. He illustrates his cosmological order by using the analogy of the state, where everyone obeys and imitates the king. All smaller social units in the kingdom, like the family, are subordinate to the head, which is ultimately under the authority of the king. There is a hierarchy among the spheres of celestial beings, based on their "nobility" (sharaf) and not, as Avicenna held, on their order in emanation. Of course, the order of nobility parallels emanation's order, for the hierarchical order is that which we see in the universe, the fixed stars, the planets, the moon and the earth. Like a king, the Prime Mover imparts motion only to the First Body (the sphere of the fixed stars), which becomes the intermediary for the other bodies. This leads to the other spheres (i.e. planets) to desire both the Prime Mover and the First Body, which, according to Ibn Rushd, explains how the celestial bodies move from east to west at one time and from west to east at another time. It is the desire of one that moves the planets in one way, and the desire of the other that moves them in the opposite direction.

Ultimately, as H. Davidson notes, Ibn Rushd has a cosmos in which the earth is its physical center. Surrounding the earth, at different levels, are the celestial spheres, which contain celestial bodies (e.g. the sun, moon, stars and planets), which all revolve around the earth. The motion of these spheres is attributed to immortal intelligences, governed by a primary immutable and impersonal cause. Each sphere exists in its own right, though somehow the intelligence is caused by the Prime Mover, and it is through their contemplation of the Prime Mover they receive perfection equivalent to the position they hold in the cosmological hierarchy. As such, God no longer is restricted to being a cause of one thing. The active intellect is the last sphere in the hierarchy, but is not the product of another, and like the other intelligences its cognition is fixed on God. This idea has significant influence on Ibn Rushd's doctrine of the human soul and intellect.