ABSTRACT
There is a bewildering diversity among seventeenth century theorists of perception. They do not always agree on what questions should be asked, let alone the answers or the methodology that should be used to find those answers. However, a few central questions arise within almost all seventeenth century theories of perception. The first such question concerns the nonmental aspects of perception. Some early modern philosophers paid a great deal of attention to the workings of the human perceptual apparatus. But even those who are not interested in the physiology of perception – like Leibniz and Locke – confront a more fundamental metaphysical question:
What must the external world be like for human beings to know it through sense perception?
This is a question faced by all theories of perception. But it is particularly salient for the mechanical philosophers of the seventeenth century. A central theme in the neo-Aristotelian theories that mechanism was intended to replace is that perception involves – indeed, requires – resemblance. Perception, neo-Aristotelians hold, occurs when the perceiver’s soul comes to resemble the external object or quality it represents. This resemblance typically consists in shared form, and it is guaranteed by the transmission of intentional species. The philosophers I discuss next all reject this picture out of hand, because they reject the forms and species involved. Thus, they owe us another account of the metaphysics of the external world, one that makes it perceptible in their terms.