This paper explores the question of Leibniz's contribution to the rise of modern "science". 1 To be sure, it is now generally agreed that the modern category of "science" did not exist in the early modern period. At the same time, this period witnessed a very important stage in the process from which modern science eventually emerged. I will argue that Leibniz made a distinctive contribution to the journey from natural philosophy to natural science, and to the modern distinction between science and philosophy, through the development of a conception of physics as an autonomous enterprise. The terminology here is notoriously slippery, and some preliminary clarifications are therefore in order. When early modern authors use the word scientia, the closest translation is normally "knowledge" rather than "science". At the centre of Leibniz's scientific ambitions is a projectthe scientia generaliswhich looks prima facie very different from what we would nowadays call "science". If these authors ever drew a distinction between philosophia and scientia, it would look very different from what is now commonly meant by the distinction between philosophy and science. Similar considerations apply to the distinction between physics (intended here primarily as the study of the motion of bodies under the action of forces) and metaphysics.