Abstract

According to Kant’s Metaphysical Foundations of Natural Science, a proper science is organized according to rational principles and has a pure a priori rational part, its metaphysical foundation. In the second edition Preface to the first Critique, Kant claims that his account of time explains the a priori possibility of Newton’s laws of motion. I argue that Kant’s proof of the law of inertia fails, and that this casts doubt on Kant’s enterprise of providing a priori foundations for Newton’s physics.