---Werner Heisenberg
The Historical Development of Quantum Theory, Vol. 3:
The Formulation of Matrix Mechanics and Its Modifications, 1925-1926
by Jagdish Mehra and Helmut Rechenberg,
Springer-Verlag, New York, 1982, p. 94.
This quote, where it is used as an
epigraph on p. 172 in Operator Commutation Relations by
Palle E. T. Jorgensen and Robert T. Moore, D. Reidel, Dordrecht / Boston / Lancaster, 1984,
is cited incorrectly to p. 227 of the Mehra-Rechenberg work.
Of
course Max Born cleaned up a lot of the math that Heisenberg didn't
understand,
and that is sort of what the Heisenberg quote is hinting at. And it
is
also the main thrust of vol. 3 of the Mehra-Rechenberg book set.
It says that Heisenberg learned an important lesson from
the
work of Born and Jordan in 1926 (aside from not sleeping in Hilbert's
classes!), and the lesson is the statement of Heisenberg which is quoted on p.
94. Mehra had taped and transcribed a large
number
of conversations he had over a period of years with Heisenberg, and they are
cited with page numbers at many places throughout the book set, and this
particular quote is cited as: Heisenberg, Conversations, pp. 163-164.
When I have advised my Ph.D. students
in their thesis work, I must have used some version of this sentence from
Heisenberg a large number of times, sometimes several times in one day.
Some interesting Heisenberg links:
Heisenberg / Uncertainty Principle - Werner Heisenberg and the Uncertainty Principle
Werner Heisenberg Winner of the 1932 Nobel Prize in Physics
Copenhagen . Werner Heisenberg | PBS
I like to read papers and books by Werner Heisenberg, and am
struck by how strong a turning point in his life and his thinking was the
Fall of 1941.
I think that he never made peace with himself after the meeting with Bohr.
After I started to think about sources, I was struck by some newly released
letters from Bohr
that put the play
Copenhagen
(by Michael Frayn) in a different light. I
also found it touching that much of the correspondence between Bohr and
Heisenberg was in Danish.
There were quite a number of books about
Heisenberg that came out before Michael Frayn's play was written. And there
were some that came after. An interesting one was by Heisenberg's widow,
Elizabeth. You can guess which part of the spectrum this book covered. It is
worth reading all the same. The books in their totality cover quite a broad
spectrum of interpretations, more or less the spectrum of possibilities from
the play itself. My impression is that the transcripts from the 1945 Farm
Hall internment of the German nuclear scientists were made public several
years after Frayn had finished writing his play. But the Farm Hall
transcripts weren't conclusive. I read them. However they certainly didn't
throw a positive light on Heisenberg's motives. Others of the contemporaries
wrote about this too, such as Lise Meitner, who had escaped to Sweden in the
war years. Lise Meitner is a counter balance to the spin from Elizabeth
Heisenberg's book. (I have an amazon
list
with some of these biographies.)
Werner Heisenberg's father had died when WH was 29, and Bohr became close to
being a substitute father from then on. In the play, you hear the haunting
sound of sea gulls in the background. The only prop in the entire play!
Niels Bohr's oldest son had drowned in a sailing accident, and this sound
effect from the play may be a reminder that Bohr was losing another son at
the time of the 1941 meeting. Their personal bond was very strong. So that
was probably also one reason why Bohr's letters were never sent, and weren't
meant to be released. Well the Bohr family finally did decide to make them
public in 2002; i.e., many years after Frayn's writing. I can't quite make
out how well Frayn knew the Bohrs, but he has researched his subject to an
impressive degree. I have a feeling that the play might well have gotten a
different twist if Frayn had known about Bohr's letters. Bohr was always so
extremely careful in his formulations, and I hesitate to attempt to
summarize Bohr's letters; but I think you will find them interesting.
http://www.nbi.dk/NBA/release.html