1 GOD’S EXISTENCE Robert C. Koons 1. INTRODUCTION The so‐called “cosmological argument” (as it was first labeled by Immanuel Kant) has played a central role within Aristotelian philosophy from the very beginning. In fact, we find first‐cause arguments before Aristotle: most importantly, in Plato’s The Laws, Book X. The inference to the existence of a god or gods is central to Aristotle’s two most important works in metaphysics, Physics and Metaphysics. The Neo‐Platonists (including Plotinus and Proclus), who saw themselves as building on Aristotle’s foundations, made this argument fundamental to their understanding of reality. Many of the ancient critics of Aristotle, such as John Philoponus, the Kalām tradition (al‐Kindī, al‐Ghazzālī), and Bonaventure, drew heavily from Aristotle in their philosophizing, and here too the cosmological argument took central stage. Finally, this argument continued to influence modern philosophy, in both its rationalist (Descartes, Spinoza, Leibniz, the pre‐critical Kant) and empiricist (Locke, Samuel Clarke) varieties. This continuity demonstrates that modern philosophy retained more Aristotelian elements than is often recognized. No revival of the Aristotelian tradition in metaphysics can afford to ignore the question of the viability of first‐cause arguments. In fact, there has been a flourishing of first‐cause argumentation within analytic metaphysics in the last fifteen years, a development with parallels in other branches of the field. In the section 2 below, I deal with some preliminary issues about the form of the argument. I take on the most important question, that of justifying some form of a