While Voltaire’s attacks on Maupertuis crossed the line into ad hominem, at their core was a fierce defense of the way that metaphysical reasoning both occludes and deludes the work of the physical scientist. Moreover, to the extent that eighteenth-century Newtonianism provoked two major trends in later philosophy, first the reconstitution of transcendental philosophy à la Kant through his “Copernican Revolution” that relocated the remains of metaphysics in the a priori categories of reason, and second, the marginalization of metaphysics altogether through the celebration of philosophical positivism and the anti-speculative scientific method that anchored it, Voltaire should be seen as a major progenitor of the latter. By also attaching what many in the nineteenth century saw as Voltaire’s proto-positivism to his celebrated campaigns to eradicate priestly and aristo-monarchical authority through the debunking of the “irrational superstitions” that appeared to anchor such authority, Voltaire’s legacy also cemented the alleged linkage that joined positivist science on the one hand with secularizing disenchantment and dechristianization on the other. In this way, Voltaire should be seen as the initiator of a philosophical tradition that runs from him to Auguste Comte and Charles Darwin, and then on to Karl Popper and Richard Dawkins in the twentieth century.