Margaret Cavendish’s views about the nature of bodies and perception leave her with a potentially problematic implication: that light has no role in visual perception. For her, perception occurs through the self-motion of animate matter, not through a mechanical system that appeals to local motions and collisions of contiguous bodies. This means that motion is not transferred from external objects with light playing a mediating role; the matter of our eyes simply moves itself to copy the sensible qualities of external (...) bodies. However, Cavendish cannot ignore the simple empirical fact that we appear to have visual perceptions in the presence of light but not in the presence of darkness. Light must play some role. I argue that light for Cavendish plays an intermediary role but does not transfer motions as the mechanical model suggests. Rather, light behaves like our eyes by moving itself to form copies of external objects. Our eyes then see these copies. For Cavendish, we are directly acquainted with a “veil of light” rather than the objects themselves. (shrink)

The nature of light is a focus of Thomas Hobbes’s natural philosophical project. Hobbes’s explanation of the light of lucid bodies differs across his works, from dilation and contraction in Elements of Law to simple circular motions in De corpore. However, Hobbes consistently explains perceived light by positing that bodily resistance generates the phantasm of light. In Letters I.XIX–XX of Philosophical Letters, fellow materialist Margaret Cavendish attacks the Hobbesian understanding of both lux and lumen by claiming that Hobbes has illicitly (...) made abstractions from matter. In this paper, I argue that Cavendish’s criticisms rely on an incorrect understanding of the nature of Hobbesian geometry and the role it plays in Hobbes’s natural philosophy. Rather than understanding geometry as wholly abstract, Hobbes attempts to ground geometry in different ways of considering bodies and their motions. Furthermore, Hobbes’s own criticisms of abstraction suggest that he would share many of the worries she raises but deny that he falls prey to them. (shrink)