Celia Hatherly

According to Avicenna, whatever exists, whenever it exists, exists of necessity. Not all beings, however, exist with the same kind of necessity: some things exist necessarily per se and others necessarily per aliud. Avicenna on the Necessity of the Actual: His Interpretation of Four Aristotelian Arguments explains how Avicenna’s modal claims show that God is the first efficient and the ultimate final cause of an eternally existing cosmos. In particular, Celia Kathryn Hatherly shows how Avicenna uses four Aristotelian arguments to prove this very un-Aristotelian conclusion. These arguments include Aristotle's argument for the finitude of efficient causes in Metaphysics 2; for the prime mover in the Physics and Metaphysics 12; for the mutual entailment between the necessary and the eternal in De Caelo 1.12; and against the Megarians in Metaphysics 9. Moreover, Hatherly contends, when Avicenna's version of these arguments is interpreted using his distinctive understanding of modality, the objections of his contemporaries and modern scholars fail.

Avicenna's proof for the existence of God (the Necessary Existent) in the Metaphysics of the Salvation relies on the claim that every possible existent shares a common cause. I argue that Avicenna has good reason to hold this claim given that he thinks that (1) every essentially ordered causal series originates in a first, common cause and that (2) every possible existent belongs to an essentially ordered series. Showing Avicenna's commitment to 1 and 2 allows me to respond to Herbert Davidson's and Richard Swinburne's claim that Avicenna's proof for the Necessary Existent is incomplete and fallacious