Copenhagen and Niels Bohr

This chapter addresses the question of how the Danish capital Copenhagen became the embodiment of the philosophical implications of quantum physics, and it discusses some of Niels Bohr’s main ideas in this Copenhagen Interpretation, including complementarity. The chapter suggests that the combination of a favourable Danish science policy with Bohr’s eminent skills as fundraiser and in scientific leadership, paved the way for the small hitherto scientifically peripheral Kingdom of Denmark to be able to foster one of Europe’s leading scientific centers in the interwar years, viz. the Institute for Theoretical Physics. With respect to the interpretation of quantum mechanics the chapter emphasises that Bohr saw quantum physics as an epistemological rather than an ontological theory. Bohr’s focus on the role of measurement in quantum physics is outlined, and how this was discussed and elucidated in Copenhagen through idealised thought experiments. The chapter concludes with a brief review of how the physicists in Copenhagen responded to the new critique and development of the interpretation of quantum physics after the Second World War.