Ernan McMullin (1924–2011) was John Cardinal O'Hara Professor Emeritus of Philosophy at the University of Notre Dame.

"A major contribution to the growing literature on Newton. . . . Drawing upon both Newton's published and unpublished writings, McMullin explores the more metaphysical side of Newton's physics--questions regarding the nature of matter, force, aether, spirit, and the void--rather than the mathematical and more positivistic side." —Choice"In this delightfully brief and trenchant book Ernan McMullin elevates several current problems in Newtonian scholarship to a new level of sophistication." —Eighteenth-Century Studies"While McMullin's study is indebted to the work of contemporary Newton scholars, his arguments are frequently original and he tackles tangled topics with circumspection and admirable clarity. This closely argued book is an up-to-date and judicious study of Newton's natural philosophy, providing a critical survey of a convoluted area of scholarship. In clarifying Newton's ontology, McMullin has made a valuable contribution to Newtonian studies." —International Studies in Philosophy