which Alexander argues against the Stoic doctrine of necessity. In On Fate Alexander denied three things - necessity (), the foreknowledge of fated events that was part of the Stoic identification of God and Nature, and determinism in the sense of a sequence of causes that was laid down beforehand () or predetermined by antecedents (). He defended a view of moral responsibility we would call libertarianism today. On Mixture and Growth discusses the topic of mixture of physical bodies. It is both an extended discussion (and polemic) on Stoic physics, and an exposition of Aristotelian thought on this theme. On the Principles of the Universe is preserved in Arabic translation. This treatise is not mentioned in surviving Greek sources, but it enjoyed great popularity in the Muslim world, and a large number of copies have survived. The main purpose of this work is to give a general account of Aristotelian cosmology and metaphysics, but it also has a polemical tone, and it may be directed at rival views within the Peripatetic school. Alexander was concerned with filling the gaps of the Aristotelian system and smoothing out its inconsistencies, while also presenting a unified picture of the world, both physical and ethical. The topics dealt with are the nature of the heavenly motions and the relationship between the unchangeable celestial realm and the sublunar world of generation and decay. His principal sources are the Physics (book 7), Metaphysics (book 12), and the Pseudo-Aristotelian On the Universe. On Providence survives in two Arabic versions. In this treatise, Alexander opposes the Stoic view that divine Providence extends to all aspects of the world; he regards this idea as unworthy of the gods. Instead, providence is a power that emanates from the heavens to the sublunar region, and is responsible for the generation and destruction of earthly things, without any direct involvement in the lives of individuals. Influence By the 6th century Alexander's commentaries on Aristotle were considered so useful that he was referred to as "the commentator" (). His commentaries were greatly esteemed among the Arabs, who translated many of them, and he is heavily quoted by Maimonides. In 1210, the Church Council of Paris issued a condemnation, which probably targeted the writings of Alexander among others. In the early Renaissance his doctrine of the soul's mortality was adopted by Pietro Pomponazzi (against the Thomists and the Averroists), and by his successor