Spinoza and Christiaan Huygens: The Odd Philosopher and the Odd Sympathy of Pendulum Clocks
Abstract. In 1665, in a response to a question posed by Robert Boyle, Spinoza gave a definition of the coherence between bodies in the universe that seems to be inconsistent both with what he had written in a previous letter to Boyle (1661) and with what he would later write in his main work, the Ethics (1677). Specifically, Spinoza’s 1665 letter to Boyle asserts that bodies can adapt themselves to another body in a non-mechanistic way and absent the agency of an external cause. This letter – Letter 32 – seems therefore to be in clear contradiction with the metaphysical determinism that is an important and characteristic element of his philosophy. This article suggests that the viewpoint expressed by Spinoza in Letter 32 may have been inspired by a spectacular discovery made by Christiaan Huygens a few months prior, namely, the self-synchronization of pendulum clocks. As I argue in this article, this new, hypothesized link to Huygens’ pendulum experiments may account for Spinoza’s otherwise paradoxical answer to Boyle in Letter 32.
Keywords: Spinoza, Christiaan Huygens, Robert Boyle, pendulum clock, synchronization.