Video from The Thomistic Institute
"The world is not a place of static individuals, but of active realities. Thomas Aquinas thought that all of reality could be classified according to the distinction between substance and accident. For Aristotle and Thomas Aquinas, substances are not inert or static entities. Whatever exists is active, and the more being a thing has, the more active it is. Substance and Accidents (Aquinas 101) - Fr. James Brent, O.P." from video introduction.