These chapters of Aristotle's treatise are about physical interactions. In his innovative commentary, Philoponus discusses Aristotle's idea that certain qualities of the elements are basic. In what way are they basic? he asks. To what extent can the other qualities be reduced to the basic ones? And if the other qualities depend on the basic ones, how is it that they can vary independently of each other when the basic qualities change? Philoponus develops the idea that the other qualities merely supervene on the basic ones, rather than resulting from them. Moreover, physical qualities admit of...

The first five chapters of Aristotle's De Generatione et Corruptione distinguish creation and destruction from mere qualitative change and from growth. They include a fascinating debate about the atomists' analysis of creation and destruction as due to the rearrangement of indivisible atoms. Aristotle's rival belief in the infinite divisibility of matter is explained and defended against the atomists' powerful attack on infinite divisibility.
But what inspired Philoponus most in his commentary is the topic of organic growth. How does it take place without ingested matter getting...