Leibniz’s Defence of Heliocentrism

Abstract

This paper discusses Leibniz’s view and defence of heliocentrism, which was one of the main achievements of the Scientific Revolution (1543-1687). As Leibniz was a defender of a strictly mechanistic worldview, it seems natural to assume that he accepted Copernican heliocentrism and its completion by figures like Kepler, Descartes and Newton without reservation. However, the fact that Leibniz speaks of the Copernican theory as a hypothesis (or plausible assumption) suggests that he had several reservations regarding heliocentrism. On a first approach Leibniz employed two of his most cherished principles to defend the Copernican hypothesis against the proponents of geocentrism: these were the principle of the relativity of motion and the principle of the equivalence of hypotheses. A closer analysis reveals, however, that Leibniz also appeals to dynamic causes of planetary motions, and these constitute a much stronger support for heliocentrism than his two philosophical principles alone.