The Doctrine of the Hiddenness of Substance

During the Early Modern period, an epistemological doctrine regarding the substance-attribute distinction was widely accepted, namely, that while attributes can be perceived, the substances that have them cannot. This peculiar view, strongly associated with John Locke, I call the hiddenness of substance doctrine, and this paper is concerned with uncovering its intellectual sources. After examining the diagnoses of some modern scholars, I trace the doctrine most fundamentally to a confusion over the apparently platitudinous claim that there is a distinction or difference between a substance and its attributes. Specifically, it is argued that there was a tendency to understand this claim in an inappropriately strong way, where the idea of being distinct was conflated with that of being separate. It is also argued that this sort of conflation can occur in other areas too, such as with philosophical reflection on the part-whole relation, so that this issue is of contemporary relevance.