The last of his kind? Gottfried Ploucquet’s occasionalism and the grounding of sense-perception

Sufficiently grounding the origin of sense-perceptions in the mind is an issue that has concerned philosophers for a long time, and remains an issue even today. In eighteenth-century Germany prior to the publication of Kant’s Critical philosophy, the two main competing theories to causally ground sense-perceptions were pre-established harmony and physical influx, the latter of which ultimately carried the day. A third option had been around in the seventeenth century: occasionalism. However, historians of philosophy believe this option to have entirely disappeared in the eighteenth century. I will show that this is not the case. In this paper, I focus on one influential German occasionalist: Gottfried Ploucquet (1716–90). Ploucquet not only criticizes Leibniz’s theory of pre-established harmony for providing an ultimately ungrounded, subjective, and arbitrary account of the origin of sense-perceptions, but also presents his own daring alternative: a representationalist-occasionalist theory that locates the objective ground of sense-perceptions in the divine mind.