Beyond Uncertainty: Heisenberg, Quantum Physics, and the Bomb

David C. Cassidy (Bellevue Literary Press, New York, 2009), 480 pp., $27.00
ISBN: 978-1-934137-13-0

Reviewed by Alvin M. Saperstein

[Editor's note: An abbreviated version of this review was published in the January 2010 edition of  Physics Today.] 

Most of our readers are aware of Germany as a fountainhead of science in the 19th and early 20th centuries. We associate science with the pinnacle of humanistic endeavors, and thus have looked to Germany as a pillar of humanism. And yet, 20th century Germany gave us Nazism, with all its bestial ties. How do we account for such a dichotomy?

David Cassidy explores this conundrum in his biography of Werner Heisenberg, born into the German professorial class, defender of the prerogatives of German academia, major contributor to the physics of fluids and elementary particles, and a founder of quantum mechanics. Offered many opportunities to join the flood of liberal academics fleeing Hitler’s pre-war Nazi Germany, Heisenberg chose to remain, becoming head of the German government’s wartime nuclear weapon applied research program and simultaneously studying abstract non-linear field theory.

This book interested me because it offers insight into the rise of modern physics as well as the rise of the extreme form of nationalism called “Nazism." This masterful combination of biography, history, and popular science speaks importantly to current difficulties in the relationship between science and society and the question of the obligation of the scientist to the world outside of his “ivory tower.”

The book begins with an incisive sketch of post-Bismarkian Germany, a quasi-feudal, class-bound society in which the children of the “non-respectable” productive classes--farmers, artisans, merchants--are pushed into the “respectable” professional class. This class, very conscious of its privileges and prerogatives and dedicated to preserving them, demonstrated very little apparent concern for extending privilege to the rest of society. Growing up in the decades immediately following the unification of Germany, Heisenberg’s circle of family, friends, fellow students, and colleagues were intensely committed to strengthening and preserving the German state, although there is little evidence of concern for the well-being of the individual German outside of their privileged circle. Werner’s father’s father was a successful master-locksmith, descendant of a long line of similar tradesmen, who became an official “Burger” of a small German city which brought him far more status than he held as a craftsman. His mother’s father was a Gymnasium (academic high school) teacher and educational administrator, but he never achieved his long-sought status of university professor. Heisenberg’s father reached the desired status of professor of classical languages at the University of Munich. Werner’s long-term goal was to succeed his teacher, Arnold Sommerfeld, in the Chair of Physics at the University of Munich, a goal encouraged by his professional colleagues but never reached because of the dissatisfaction of the local Nazi party apparatus with his political “purity.”

A defining event in Werner’s late teenage years, during his last years of Gymnasium, seems to have been the attempted post-World-War-I Communist revolution in Munich. As a member of the militaristic and nationalistic student body at his elite high school, young Heisenberg participated in the right-wing counter-revolution. Werner then met the German workingman--at the opposite end of his gun. It was during this time that he became a leader of a German equivalent of the Boy Scouts (an organization too nationalistic to be an affiliate of the actual internationally oriented Boy Scout movement), a pre-occupation with youth that he kept for most of his life.

The book then describes Heisenberg’s student and research career, working with Sommerfeld (in Munich), Born (in Göttingen) and Bohr (in Copenhagen), interacting with and sometimes competing with Schrödinger and most of the other great figures of physics in the 1920s and 1930s. We follow his development of matrix mechanics, the uncertainty principle, the quantum mechanics formalism, and the Copenhagen interpretation. We learn about his struggles with the increasing politicization of the German University and his receipt of the Nobel Prize for Physics. The actual physics content is qualitatively sketched--there are no formulas or experimental descriptions; the book’s intended audience is not “scientists as scientists.” The onset of World War II finds Heisenberg ensconced as the youngest German Professor of Physics at the University of Leipzig, where he built up a formidable research group in theoretical physics (in spite of the Nazi distaste for theoretical physics which they referred to as “Jewish science”) after turning down several offers to leave Germany for an American professorship. Except for responses to direct attacks upon himself or his science (responses in which he often "saved himself" at the expense of other considerations), Heisenberg spent these years immersed in the closed circles of his international scientific colleagues, his music (he was an excellent pianist, giving many private recitals), his youth group and its hiking activities, and his rapidly growing family. He married late, after his Nobel prize, to a much younger wife, and soon had six children with whom to be concerned.

Heisenberg’s wartime activities are the source of much controversy. Did he help or hinder the Nazi drive for nuclear weapons? Did he try, successfully or otherwise, to save fellow scientists and scholars from Nazi persecutions such as the military draft? Why did he visit his old teacher and friend, Niels Bohr, in Nazi-occupied Copenhagen? Was it to spy on Allied nuclear activities, to boast of German nuclear activities, or to signal some sort of nuclear truce with the Allies that would include the mutual cessation of weapons research? The book does a commendable job of presenting the evidence for both sides of each controversy. The book is well referenced, with 45 pages of notes. Cassidy points out the evident weaknesses of the arguments, the passage of time and memory, and the paucity of written documentation, and then allows readers to reach their own conclusions.

Controversy does not end with the end of World War II and the devastation of his beloved Germany. Heisenberg’s self-appointed task, largely successful, is to be a major factor in the rebuilding of German science to its pre-war eminence. As such, he cannot afford to be tainted with the suspicion of moral or professional lapses during the war. Hence, colleagues and friends, such as Carl Friederich von Weizächer, circulate the word that German’s failure to create a nuclear weapon during the war was due to the ethical reluctance of German physicists to provide Hitler with such weapons, rather than to any scientific or organizational failures on their part. Again, the author presents the available evidence, including the famous Farm Hall tapes. These secretly recorded British intelligence tapes were the result of eavesdropping on the technical (and personal) conversations of the captured German physics elite while they were comfortably captive in an English estate. They document the German physicists’ surprised reaction to the success of the Allied nuclear weapons program when it became evident by the destruction of Hiroshima and Nagasaki. Once again, the author lets the readers make up their own minds.

The book is interesting, well written, and amply documented. Everyone who wishes to function productively in our modern science-based society should be aware of its contents. My wife and I disagree as to whether the average American college undergraduate can productively read it. I hope to use it in a freshman/sophomore honors course for non-science students; my wife thinks I’m crazy. I urge Forum readers to read it and make up their own minds about the many questions raised in this excellent discussion of science, society, and the role of the individual scientist.

Alvin M. Saperstein
Wayne State University, Detroit

This contribution has not been peer refereed. It represents solely the view(s) of the author(s) and not necessarily the views of APS.