In these three chapters of On the Heavens, Aristotle argues that the universe in ungenerated and indestructible. In Simplicius's commentary there is a battle between the Neoplatonist Simplicius and the Aristotelian Alexander, whose lost commentary on Aristotle's On the Heavens Simplicius partly preserves. Simplicius's rival, the Christian Philoponus, had conducted a parallel battle in his Against Proclus, but had taken the side of Alexander against Proclus and other Platonists, arguing that Plato's Timaeus gives a beginning to the universe. Simplicius takes the Platonist side, denying that Plato intended a beginning. The origin to which Plato refers is, according to Simplicius, not a temporal origin, but the divine cause that produces the world without beginning.
Simplicius of Cilicia (/sɪmˈplɪʃiəs/; Greek: Σιμπλίκιος; c. 490 – c. 560) was a disciple of Ammonius Hermiae and Damascius, and was one of the last of the Neoplatonists.