This paper argues for an interpretation of Leibniz’s claim that physics requires both mechanical and teleological principles as a view regarding the interpretation of physical theories. Granting that Leibniz’s fundamental ontology remains non-physical, or mentalistic, it argues that teleological principles nevertheless ground a realist commitment about mechanical descriptions of phenomena. The empirical results of the new sciences, according to Leibniz, have genuine truth conditions: there is a fact of the matter about the regularities observed in experience. Taking this stance, however, (...) requires bringing non-empirical reasons to bear upon mechanical causal claims. This paper first evaluates extant interpretations of Leibniz’s thesis that there are two realms in physics as describing parallel, self-sufficient sets of laws. It then examines Leibniz’s use of teleological principles to interpret scientific results in the context of his interventions in debates in seventeenth-century kinematic theory, and in the teaching of Copernicanism. Leibniz’s use of the principle of continuity and the principle of simplicity, for instance, reveal an underlying commitment to the truth-aptness, or approximate truth-aptness, of the new natural sciences. The paper concludes with a brief remark on the relation between metaphysics, theology, and physics in Leibniz. (shrink)

Spending six months in Rome in 1689 Gottfried Wilhelm Leibniz (1646–1716) occupied himself with the question of Copernican and Galilean censure. An established reading of the Rome papers suggests that Leibniz’s attempt to have the Copernican censure lifted was derived solely from the equivalence of hypotheses stemming from the relativity of motion; and involved Leibniz’s compromising his belief in the truth of the Copernican hypothesis by arguing that it should only be interpreted instrumentally; and that Leibniz believed in the unrestricted (...) abolition of censure. On the contrary, I argue that if hypotheses were merely equivalent, this would not provide a reason for lifting censure of Galileo, who argued that the Earth really moves and the Church was in error on this point; that Leibniz’s position in his cosmology was indeed a kind of instrumentalism, so that it did not involve any compromise; and that Leibniz is advocating a position that Galileo should be subject to censure, not because of his physics but rather because of his misinterpretation of the status of Scripture. (shrink)