Kepler's snow: the epistemic playfulness of geometry in seventeenth-century Europe

This paper suggests that layered ontology is important within Kepler's method, and that it developed at least partially in response to a disciplinary and religious crisis. As such, and despite Platonic allegiances, it places him in a longue duree of geometrical constructivism in seventeenth-century Europe. After introducing the pivotal role of Mysterium cosmographicum (1596) and how Kepler's career may be seen in the context of courtly bricolage, the exposition realigns De nive sexangula (1611) with the mathematical communities of its time and argues in Reviel Netz's tradition that its cognitive practices enact a ludic style of demonstration. Kepler's essay on crystallography is an epistemological improvement on previous types of natural jokes.