Through a Glass Darkly: Johannes Kepler and the Camera Obscura

In his Ad Vitellionem paralipomena (Additions to Witelo, 1604), Johannes Kepler advanced the remarkable hypothesis that the act of seeing involves the painting of an inverted picture on the retina, comparable to the picture that appears on the back of the camera obscura. Indeed, it was Kepler who first drew a connection between seeing and picturing, and with it a line between picture and object (between nature and its representation) that was interlaced in Renaissance literature.

This paper has two objectives:
(1) it will look at the consequence of Kepler’s hypothesis for Scholastic theories of knowledge, that dominated intellectual life in and around the universities; and
(2) it will explore the impact of Kepler’s hypothesis on the emergence of what is now commonly regarded as modern epistemology.