. G. W. Leibniz did not contribute directly to scientific discoveries in the life sciences, but he provided several relevant analyses on methods of investigation applicable to complex, and in particular organic, phenomena. Leibniz's theory of organic bodies and his methodological model had deep and broad implications for the development of physiology at the turn of the seventeenth and eighteenth centuries. This paper focuses on a methodological issue which divided natural philosophers and physiologists during the early Enlightenment—about which Leibniz supported (...) original viewpoints which have kept a certain relevance, mutatis mutandis, in later contexts. The issue in question concerns the relation between the surface organization of phenomena and the deeper organization of underlying micro-structures and micro-processes. In a search for the sufficient reason for phenomena, hypothetical models are called upon to provide determining reasons for surface effects. These reasons represent processes involving micro-mechanisms combined so as to account for the emerging organization. (shrink)

While historians of the microscope currently consider that no programme of microscopy took place during the Enlightenment, the thesis challenges this view and aims at showing when and where microscopes were used as research tools. The focus of the inquiry is the research on microscopic animalcules and the relationship of European microscope making and practices of microscopy with topical trends of the industrial revolution, such as quantification. Three waves of research are characterised for the research on animalcules in the Enlightenment: (...) 1. seventeenth-century observations on animalcules crowned by Louis Joblot's 1718 works in the milieu of Paris Académie royale des sciences, 2. mid eighteenth-century observations and experiments on polyps and animalcules (Trembley, Baker and Hill) and, 3. between 1760 and 1790, OF Müller's establishment of the systematics of infusoria in Denmark and Germany. (shrink)