I have written or edited four philosophy books, all are mostly historical, half are on Leibniz, half are on teleology, half are on physics, and half are on religion. I am currently working on two new books on early modern philosophy. 

Saints, Heretics and Atheists: A Historical Introduction to the Philosophy of Religion

Oxford University Press, forthcoming

Saints, Heretics and Atheists offers a historical introduction to fundamental questions in the philosophy of religion. Ranging from ancient times to the twentieth century, it is divided into twenty-five succinct, chronological chapters. Individual chapters discuss, for example, Plato’s reflections on the nature of piety, Augustine’s views on freedom, al-Ghazali’s route to mysticism, Aquinas’s treatment of the nature of God, Margarite Porte’s revelations on heaven and hell, Spinoza’s suggestion that God is nature and that we are modes of God, Hume’s discussion of the argument from design, deism, and the problem of evil, Mary Shepherd’s defense of miracles, Nietzsche’s views on religious morality and the relationship between religion and nihilism. The book closes with an exploration of William James’s defense of the right to believe, possible limitations of that right, and the nature of philosophical progress.

Supplemental materials

Saints, Heretics, and Atheists is based on lectures for a course I taught for over a decade at Harvard University. I have posted a template of the syllabus (which instructors are welcome to modify and use) as well as and a list of corresponding open access primary texts


A Miracle Creed: The Principle of Optimality in Leibniz’s Physics and Philosophy (Amazon; Oxford University Press)

Oxford University Press, 2022

This book introduces Gottfried Wilhelm Leibniz’s Principle of Optimality and argues that it plays a central role his physics and philosophy, with profound implications for both. Each chapter begins with an introduction to one of Leibniz’s ground-breaking studies in natural philosophy, paying special attention to the role of optimal form in those investigations. Each chapter then goes on to explore the philosophical implications of optimal form for Leibniz’s broader philosophical system. Individual chapters include discussions of Leibniz’s understanding of teleology, the nature of bodies, laws of nature, and free will. The final chapter explores the legacy of Leibniz’s physics in light of his work on optimal form.

Supplemental materials

A Miracle Creed spotlights five groundbreaking studies published by Leibniz in the Acta Eruditorum. All five studies appear in English language translations in G.W. Leibniz: Journal Articles on Natural Philosophy, R. T. W. principal editor (Oxford University Press, forthcoming). I wrote a short piece related to the book for a popular audience for the Institute of Art and Ideas, available here.


Teleology: A History (AmazonOxford University Press)

Oxford University Press 2020

This volume explores the intuitive yet contested concept of teleology as it has been treated by philosophers from ancient times to the modern day. It includes nine main chapters centered on the treatment of teleology in Plato, Aristotle, the Islamic medieval tradition, the Jewish medieval tradition, the Latin medieval tradition, the early modern era, Kant, Hegel and contemporary philosophy. Each chapter takes up central questions such as: Is teleology intrinsic or extrinsic? Does teleology necessarily involve intentionality? What is the scope of teleology? Is teleology explanatory? The philosophical discussions of the main chapters are enlivened and contextualized by four reflection pieces exploring the implications of teleology in medicine, art, poetry and music.



G.W. Leibniz: Journal Articles on Natural Philosophy, R. T. W. Arthur principal editor

Oxford University Press, forthcoming

This is the first compilation in English of Leibniz’s journal articles on natural philosophy (written in Latin and French), presenting a selection of 26 articles, only 3 of which have appeared before in English translation. Main topics include: Leibniz’s work in optics, on the fracture strength of materials, on motion in a resisting medium, and his pioneering applications of his calculus to these issues by construing them as mini-max and inverse tangent problems; his critique of the Cartesian estimate of motive force, “quantity of motion”, and his proposal of a different way of estimating force to replace it, issuing in his measure mv2; his proposed theory of celestial motions and gravitation, and derivation of the inverse square law; challenge problems concerning the isochronous curve and the catenary; a sample of his work on gaming theory; a defense of his account of cohesion in terms of conspiring motions, and his critique of atomism.