Visualizability and Intelligibility

This chapter investigates the relation between visualizability and intelligibility, by means of an in-depth study of the transition from classical physics to quantum physics in the first decades of the twentieth century. In this development, the issue of visualizability played a central role. After a brief discussion of the visualizability of classical physics, it examines the gradual loss of visualizability in quantum theory, focusing on the work of quantum physicists Niels Bohr, Wolfgang Pauli, Werner Heisenberg, and Erwin Schrödinger. The chapter presents a detailed analysis of the role of visualizability (Anschaulichkeit) in the competition between Schrödinger’s wave mechanics and Heisenberg’s matrix mechanics, and in the discovery of electron spin. The contextual theory of understanding asserts that visualizability is one out of many possible tools for understanding, albeit one that has proved to be very effective in science. This conclusion is supported by an analysis of the role of visualization in postwar quantum physics, especially via Feynman diagrams.