What Is Real?: The Unfinished Quest for the Meaning of Quantum Physics

by Adam Becker

Research into the meaning of quantum physics was one of the casualties of the war. With all these new students crowding classrooms around the country, professors found it impossible to teach the philosophical questions at the foundations of quantum physics. Before the war, courses in quantum physics on both sides of the Atlantic, like Heisenberg’s in Leipzig and Oppenheimer’s in Berkeley, spent a great deal of time on conceptual issues. Textbooks and exams from the prewar period asked students to write detailed essays on the nature of the uncertainty principle and the role of the observer in the quantum world. But, with ballooning class sizes, detailed discussion of philosophy became all but impossible. “With these subjects [such as uncertainty, complementarity, and causality] lecturing is of little avail,” complained a physics professor at the University of Pittsburgh in 1956. “The baffled student hardly knows what to write down, and what notes he does take are almost certain to horrify the instructor.” Smaller quantum physics classes in smaller departments afforded foundational questions more time—about five times as much as larger classes—but, as enrollments surged, few small physics classes were left. The larger classes focused on “efficient, repeatable means of calculation,” rather than focusing on foundations. And textbooks nearly dropped questions about foundations altogether, as a new generation of reviewers in physics periodicals praised a new batch of texts for “...