Measuring Shadows: Kepler's Optics of Invisibility

by Raz Chen-Morris

In Measuring Shadows, Raz Chen-Morris demonstrates that a close study of Kepler's Optics is essential to understanding his astronomical work and his scientific epistemology. He explores Kepler's radical break from scientific and epistemological traditions and shows how the seventeenth-century astronomer posited new ways to view scientific truth and knowledge. Chen-Morris reveals how Kepler's ideas about the formation of images on the retina and the geometrics of the camera obscura, as well as his astronomical observations, advanced the argument that physical reality could only be described through artificially produced shadows, reflections, and refractions.

Breaking from medieval and Renaissance traditions that insisted upon direct sensory perception, Kepler advocated for instruments as mediators between the eye and physical reality, and for mathematical language to describe motion. It was only through this kind of knowledge, he argued, that observation could produce certainty about the heavens. Not only was this conception of visibility crucial to advancing the early modern understanding of vision and the retina, but it affected how people during that period approached and understood the world around them.

264 pages, Hardcover

Published January 28, 2016

Reviews

[Karl Galle · Rating 5 out of 5]

This is a really excellent and nuanced work not just on Kepler but on different intersections between thinking about reason and the senses in early modern science. It probably won't appeal to a lot of casual readers in the history of astronomy, because the analysis is pretty dense and primarily aimed at an academic audience, but the writing is clear, the book is relatively concise, and it's one of the most interesting philosophy of science works I've read in recent years. As a bonus, it includes some good original takes on why a couple of Kepler's more apparently whimsical works -- the Somnium and the Six-Cornered Snowflake -- are actually animated by serious philosophical purposes. Highly recommended for anyone who might ever be in the mood to tackle a bit of good quality muesli rather than frosted flakes regarding the post-Copernican revolution in astronomy. :-)