Act 2 begins with a recollection of Heisenberg’s first trip to Copenhagen in 1924 when, as a young man, he and Bohr went on a long hike to Elsinore. As they walked, they talked, “walking, talking, for a hundred miles” (36). But they do not remember which language they spoke together at the time. The two men reminisce about Bohr’s other assistants, most of whom became renowned scientists in their own right. Scattered across Europe, the scientists worked together to solve the cutting-edge problems that concerned physicists, sending each other their work constantly. Heisenberg describes the era as “a new Enlightenment” (39). Margrethe asks whether the two men were trying to relive this moment in 1941.

Margrethe points out that many of their greatest achievements were not made together but when the two men were apart. Both Bohr and Heisenberg are misremembering their time together. Margrethe gently teases Heisenberg, who is still annoyed that his major breakthroughs were not as well understood as those of Schrodinger. It reached a point where Bohr felt he had to intervene, inviting Schrodinger to Copenhagen to settle their professional rivalry and animosity. Heisenberg met Schrodinger at the station and, “before he’s even got his bags off the train” (41), began to argue with him about physics.