Werner Heisenberg - Physics and Beyond: Encounters and Conversations

From school I did not go straight on to the university; there was a sharp break in my life. After my matriculation, I went on a walking tour through Franconia with the same group of friends, and then I fell seriously ill and had to stay in bed for many weeks. During my long recuperation, too, I was locked away with my books. In these critical months I came across a work that I found extremely fascinating, though I was unable to understand it fully. The author was the famous mathematician, Hermann Weyl, and the book was entitled Space, Time and Matter. It was meant to provide a mathematical account of Einsteins relativity theory. The difficult mathematical arguments and the abstract thought underlying that theory both excited and disturbed me, and, in addition, confirmed me in my earlier decision to study mathematics at the University of Munich.

During the first days of my studies, however, a strange and, to me, most surprising event took place, which I should like to report in brief. My father, who taught Middle and Modern Greek at the University of Munich, had arranged an interview with Ferdinand von Lindemann, the professor of mathematics, famous for his solution of the ancient problem of squaring the circle. I intended to ask permission to attend his seminars, for which I imagined my spare-time studies of mathematics had fully prepared me; but when I called on the great man, in his gloomy first-floor office furnished in rather formal, old-fashioned style, I felt an almost immediate sense of oppression. Before I could utter a word of greeting to the professor, who rose from his chair very slowly, I noticed a little black dog cowering on the desk, and was forcefully reminded of the poodle in Fausts study. The little beast looked at me with undisguised animosity; I was an unwelcome intruder about to disturb his masters peace of mind. I was so taken aback that I began to stammer, and even as I spoke it dawned on me that my request was excessively immodest. Lindemann, a tired-looking old gentleman with a white beard, obviously felt the same way about it, and his slight irritation may have been the reason why the small dog now set up a horrible barking. His master tried to calm him down, but the little beast only grew more hysterical, so that we could barely hear each other speak. Lindemann asked me what books I had recently been reading, and I mentioned Weyls Space, Time and Matter. As the tiny monster kept up his yapping, Lindemann closed the conversation with In that case you are completely lost to mathematics. And that was that.

Clearly mathematics was not for me. A somewhat wearing consultation with my father ended with the advice that I ought to try my hand at theoretical physics. Accordingly, he made an appointment with his old friend Arnold Sommerfeld, then head of the Faculty of Theoretical Physics at the University of Munich and generally considered one of the most brilliant teachers there. Sommerfeld received me in a bright study with windows overlooking a courtyard where I could see a crowd of students on benches beneath a large acacia. The small squat man with his martial dark mustache looked rather austere to me. But his very first sentences revealed his benevolence, his genuine concern for young people, and in particular for the boy who had come to ask his guidance and advice. Once again the conversation turned to the mathematical studies I had pursued as a hobby while still at school, and to Weyls Space, Time and Matter. Sommerfelds reaction was completely different from Lindemanns.

You are much too demanding, he said. You cant possibly start with the most difficult part and hope that the rest will automatically fall into your lap. I gather that you are fascinated by relativity theory and atomic problems. But remember that this is not the only field in which modern physics challenges basic philosophical attitudes, in which extremely exciting ideas are being forged. To reach them is much more difficult than you seem to imagine. You must start with a modest but painstaking study of traditional physics. And if you want to study science at all, you must first make up your mind whether you want to concentrate on experimental or theoretical research. From what you have told me, I take it that you are much keener on theory. But didnt you do experiments and dabble with instruments at school?

I said that I used to like building small engines, motors and induction coils. But, all in all, I had never been really at home in the world of instruments, and the care needed in making relatively unimportant measurements had struck me as being sheer drudgery.

Still, even if you study theory, you will have to pay particular attention to what may appear trivial little tasks. Even those who deal with the larger issues, issues with profound philosophical implicationsfor instance, with Einsteins relativity theory or with Plancks quantum theoryhave to tackle a great many petty problems. Only by solving these can they hope to get an over-all picture of the new realms they have opened up.

Even so, I am much more interested in the underlying philosophical ideas than in the rest, I said rather bashfully.

But Sommerfeld would have none of this. You must remember what Schiller said about Kant and his interpreters: When kings go a-building, wagoners have more work/ At first, none of us are anything but wagoners. But you will see that you, too, will get pleasure from performing minor tasks carefully and conscientiously and, lets hope, from achieving decent results.

Sommerfeld then gave me a few more hints about my preliminary studies, and said that he might well come up with a little problem connected with recent developments in atomic theory on which I could try my mettle. And it was decided that I would join his classes for the next few years.

This, my first conversation with a scholar who really knew his way about in modern physics, who had personally made important discoveries in a field impinging on both relativity and quantum theory, had a lasting effect upon me. Though his call for care in small details struck me as eminently reasonableI had heard it often enough from my own fatherI felt dejected at the thought that I was still such a long way from the field that really interested me. No wonder that this interview became the subject of many discussions with my friends. I remember one of these particularly well: it bore on modern physics and the culture of our time.

That autumn, I saw a great deal of the boy who had played Bachs Chaconne so magnificently in Prunn Castle. We would meet in the house of our mutual friend, Walter, himself a fine cellist, and practice for a private recital of Schuberts B Major Trio. Walters father had died at an early age, and his mother had been left to care for her two sons in a large and very elegantly furnished house in Elisabeth Strasse, just a few minutes walk from my parents house in Hohenzollern Strasse. The magnificent Bechstein grand in the living room was an added reason for our frequent visits. After we had finished playing, we would often talk deep into the night, and it was on one such occasion that the conversation came round to my proposed studies. Walters mother wondered why I had not decided to make music my career.

From the way you play and speak about music, I get the impression that you are much more at home with art than with science and technology, that you prefer the muses to scientific instruments, formulae and machinery. If I am right, why ever have you chosen natural science? After all, the future of the world will be decided by you young people. If youth chooses beauty, then there will be more beauty; if it chooses utility, then there will be more useful things. The decision of each individual is of importance not only to himself but to the whole of mankind.