Volume 3, Issue 1, Spring 2014
Instruments and Arts of Inquiry: Natural History, Natural Magic and the Production of Knowledge in Early Modern Europe
Thinking with optical objects: glass spheres, lenses and refraction in Giovan Battista Della Porta’s optical writings
In the Natural magic and On refraction Giovan Battista Della Porta gave the first detailed accounts of optical effects produced with the spherical mirrors and lenses which had recently become popular in Europe. These writings have received a largely negative treatment in the historiography of early modern optics, which has focused on the development of theories of light and vision. Reassessing the significance of the work of Della Porta, I shall argue that they are a most valuable source to reconstruct how the systematic study and conceptualization of new optical artifacts was a key factor in the development of geometrical optics. Della Porta’s optical experiences with glass spheres and lenses can in my opinion be understood as part of a process of “thinking with objects” similar to that described by Domenico Bertoloni Meli (2006) in the case of early modern mechanics. It was a process in which Della Porta conceptualized complex optical artifacts in terms of simpler ones, transforming them into philosophical instruments whose workings could be subsumed under a small number of rules and providing the necessary epistemic framework in which, later on, the sinus law of refraction could be formulated.