Chapter 7 examines the Fourth Way, which argues from the gradations of being, truth, goodness, and other perfections found in things, to a first cause utmost in being and perfection. After a translation and the premises are given, the chapter explains what assigning a gradation of these terms involves for Aquinas. There is discussion of a key implication of the Five Ways that God is “subsistent being itself,” that God’s essence is God’s existence. Next, there is a discussion of the premise that there is a maximum in every genus which is the cause of all other things in that genus. Thus, there is a maximum in being, truth, and goodness which causes these in all other things. This is God. A closing section discusses the doctrine of continuous creation in Aquinas, that God sustains all else in existence at every moment. There is a look at the contemporary debate over the need for a God to do this, which is termed divine conservation versus existential inertia.

Chapter 2 covers elements in Aquinas’s metaphysics and his views on causation as part of the philosophical background for understanding the Five Ways. Attention is given to Aristotle’s explanations of change and his four causes: material, formal, efficient, and final. The chapter then examines Aquinas’s metaphysics of existence and his distinction between essence and existence, which features a contrast between caused and uncaused existence prominent in the Five Ways. There is a brief look at some more recent views of existence influenced by Immanuel Kant and others, which call Aquinas’s views into question. Finally, the chapter explains Aquinas’s model of explanation, that is, his views on what needs accounting for and how it is to be done. (There is some contrast with Gottfried Wilhelm Leibniz’s views.) Aquinas seeks a complete account for why contingently existing individual objects exist at all and undergo changes. He thinks that what has caused existence must ultimately be accounted for by what has uncaused existence.