Descartes’s /Principles of Philosophy/ (1644) and Newton’s /Principia mathematica/ (1687) are two of the most important works of seventeenth century natural philosophy. Yet, when put side by side, it is far easier to identify differences between the texts than it is to pin-point similarities. Their laws of nature are a case in point. Descartes deduces his three laws from our knowledge of God and claims, in turn, that these laws are true insofar as they capture the world as God actually created it.Newton, in contrast, “deduces” his laws of motion “from the phenomena,” and his presentation suggests that these laws are true of the world just insofar as it is presented to our senses. In this talk, Domski will first clarify the different methods used by Descartes and Newton to “deduce” their laws of nature and underscore the importance of their competing notions of truth for understanding what their laws are meant to capture. Based on this treatment, she will highlight a significant and frequently overlooked point of agreement:Both Descartes and Newton adopt methods for establishing true laws of nature that allow us to know /that/ bodies obey particular laws without a complete understanding of /why/ they do, i.e., without requiring that we identify the natural processes and properties that explain the behaviors that the laws describe.