Islamic Philosophies

The brilliant Persian philosopher, physician, and vizier Avicenna (Ibn Sina; 980–1037) was born in the village of Afshanah near Bukhara in present-day Uzbekistan. A diligent and exceptionally insightful student according to his own autobiographical account, Avicenna mastered medical, legal, scientific, and philosophical studies in short order and went on to develop his own philosophical teachings. The context in which he worked was that of the harmonization of the philosophies of Plato and Aristotle and the effort to bring about a complete and consistent teaching of the sort found in the late commentator Ammonius and pursued by al-Farabi, whose work guided Avicenna's understanding of Aristotle's Metaphysics. From this and his studies of Islamic theology, Avicenna crafted a new synthesis most evident in his broadly influential teachings on God as the Necessary Being and the human soul's separability from the body.

Avicenna's arguments for the Necessary Being appear in a number of important works. In the Metaphysics of his Shifa' (Healing), the argument that leads to the Necessary Being begins in book 1, chapter 5, which is on being (mawjud) and thing (shay'). There Avicenna writes that there are three first intentions that arise initially in the soul: being or existent, thing, and necessary. These are primary intentions that naturally arise as first principles grasped by the mind in the consideration of reality in any of its forms. But apprehended quiddity or essence has of its very nature an indeterminate openness to various sorts of existence determined by something outside the essence. The arguments for the existence of the Necessary Being then proceed by rejection of the impossibility that all beings are merely possible or contingent and the acceptance that there must be necessary being for the actual existence. Since there cannot be an infinite regress of beings necessary by another, Avicenna concludes that there must be a first, the unique Necessary Being that causes the existence of the dependent necessary and possible beings and is itself uncaused. This analysis leads to the Avicennian distinction of essence and existence so influential in Arabic philosophy and in the Latin West. The First is the True One that is existence alone, free of the limitation of form, while all other things are form and being received ultimately from God. Causality here is by way of emanation, as with al-Farabi, in a hierarchy of necessary beings, except that for Avicenna there is an emanation of an intellect, a celestial sphere, and a celestial soul associated with the celestial intellect as its mover. Holding firm to the principle "from one only one can arise," Avicenna asserted that there first was emanated an intellect and from that plurality arose. This emanation continues down to the level of the moon, at which point the agent intellect generated the world and all the forms in it.

This agent intellect is denominated the "giver of forms" because it gives forms both to human minds and to natural entities of the world. The human soul has a temporal origination and its individuation in being is the result of its association and joining with the body. But its nature as intellectual shows that it is not merely the form of a body. Rather, its nature as rational indicated to Avicenna that the soul is incorruptible and that it does not die with the death of the body. This is illustrated (not proved) by the famous "Flying Man" argument which holds that it can be imagined that even if a man is suspended in the air and in complete sensory deprivation as if bodiless, he would nonetheless affirm his existence as a rational soul. According to his Letter to Kiya, the key principle is found in Aristotle's discussion of the atomism of Democratus in the De Anima and the notion that intelligibles can only exist in immaterial subjects. The common explanation that these intelligibles come to be in the soul by emanation when the soul is prepared for their reception and not by true abstraction has been challenged recently with texts suggesting a greater role for the activities of the soul itself. Still for Avicenna the soul of a prophet has special powers of imagination to receive intelligibles directly from the agent intellect and to communicate them to the people in religious discourse.

Avicenna's philosophy dominated the tradition that continued to develop after his death even after the harsh attacks of the Ash'ari theologian Abu Hamid Muhammad al-Ghazali (1058–1111). In the Incoherence of the Philosophers, al-Ghazali attacked the thought of the philosophers (al-Farabi and Avicenna) as insufficiently founded and also as contrary to Islam on the eternity of the world, God's knowledge of particulars, and the resurrection of the body. While the stated purpose of this work is to undermine the pronouncements and arguments of the philosophers, al-Ghazali's own Ash'ari occasionalism plays a role, for example, when he argues that there is no necessary connection but rather only habitual association between what are customarily called cause and effect. Such connections must be traced to divine will and power and are not found in the natures of things themselves.