In my dissertation, Beneath the Visible: The Nature of the Sub-Visible World in Early Modern Microscopy, I show how a new observational practice, microscopy, led late 17th century natural historians to give up on their view of nature based on reductive mechanism and to re-imagine it as multi-layered and full of new structural levels. Toward the end of the 17th century, the notion that natural phenomena could be fully explained through their micro-constituents (atoms, particles, corpuscles) began to lose currency as microscopic observations of new sub-visible entities started to crop up. These entities were of a smaller scale than well-known middle-scale entities, but they were not necessarily simpler or purely mechanical: Antoni van Leeuwenhoek found micro-biological animalcules in male semen, Jan Swammerdam found proof of God’s omnipotence in the smallest insects and Nehemiah Grew found essential salts the physiology of plants. All the while John Locke and Gottfried Wilhelm Leibniz debated whether this newly found sub-visible world could be integrated into the well-known world of unenhanced sense perception. This new use of the microscope also changed the relation between laboratory and field work, scientific visualization strategies and disciplinary boundaries. Through observation, experimentation and natural-philosophical argumentation the sub-visible world was explored and delimited from the visible and invisible worlds. In the process, a deep and stratified nature emerged and the microscopist was identified as the scientific persona who could peer into its sub-visible levels.
