What is "A Law of Nature"? It's a question that's vexed philosophers and scientists ever since Descartes first coined the term. Fr. Andrew Younan explores it in this insightful book. After carefully reviewing the positions of Humeans and Anti-Humeans, he employs the philosophy of Aristotle and Aquinas to argue for an essentialist understanding. His study leads him back to the beginnings of modern science and then forward to quantum mechanics. The philosophical account of how the laws of nature arise from observed regularities in the world is followed by a theological discussion of the nature and action of the Lawgiver."—from the foreword by Michael J. Dodds, OP To borrow a phrase from Galileo: What does it mean that the story of the creation is "written in the language of mathematics?" This book is an attempt to understand the natural world, its consistency, and the ontology of what we call laws of nature, with a special focus on their mathematical expression. It does this by arguing in favor of the Essentialist interpretation over that of the Humean and Anti-Humean accounts. It re-examines and critiques Descartes' notion of laws of nature following from God's activity in the world as mover of extended bodies, as well as Hume's arguments against causality and induction. It then presents an Aristotelian-Thomistic account of laws of nature based on mathematical abstraction, necessity, and teleology, finally offering a definition for laws of nature within this framework.