The Scientific Revolution completely transfigured the European intellectual landscape. Old divisions disappeared, while new fault lines emerged. Ancient philosophical sects had been replaced by new schools, featuring novel masters, disciples, and methodological commitments. However, the new schools still engaged in antagonistic discourse, attacking one another along new fronts—e.g., Cartesians against Gassendists, Newtonians against Leibnizians. This chapter presents the diverse philosophical camps that arose in the later stages of the Scientific Revolution by noting a shift in the use of the term ‘sect’. While it still signified something like an Ancient philosophical school for some, it could also take on a more negative polemical meaning, intended to disparage one’s opponents. Moreover, the individuals associated with the “sects” did not all faithfully subscribe to explicit, coherent, and systematic programs. On the contrary, declaring membership of a sect was as often a signal of opposition as of allegiance to a methodology or theory. Despite calls for conciliatory research programs, sectarian attitudes did not disappear by 1750, but delineated new battle lines between the Cartesians, the Leibnizians, and the Newtonians.

In the last thirty years, both the belief that the mechanical philosophy is an adequate historical category and the conviction that it made a positive contribution to the sciences were deconstructed. Hence the question addressed in this chapter: What to do with the mechanical philosophy? The chapter begins with a terminological enquiry about ‘mechanical philosophy’ as an emic category, and compares the use of the term on the Continent and across the Channel. It is then suggested that we examine controversies in which mechanical philosophers, having defined themselves in opposition to other natural philosophers, made explicit their expectations with regard to physical explanations. Three such controversies are discussed: one about the motion of the heart (Descartes versus Plempius); one about the elasticity of the air (Boyle versus More); and one about the universal attraction of bodies (Huygens and Leibniz versus Newton). Finally, to counter negative evaluations of the mechanical philosophy, the chapter points out the cognitive advantages of structural explanations, to which the mechanical explanations belonged.