Carl Ludwig Siegel: number thoery, pig and nazional socialism

via Lang, S. (1994). Mordell's review, Siegel's letter to Mordell, diophantine geometry, and 20th century mathematics. Mitteilungen der Deutschen Mathematiker-Vereinigung, 2(4), 20-31.

This is the letter that the german mathematician Carl Ludwig Siegel wrote to Louis Mordell about the book Diophantine geometry by Serge Lang. Here I proposed you an extract in which we can read Siegel approach to mathematics and also his political position about nazism:

When I first saw [Lang's Diophantine geometry], about a year ago, I was disgusted with the way in which my own contributions to the subject had been disfigured and made unintelligible. My feeling is very well expressed when you mention Rip van Winkle!
The whole style of the author contradicts the sense for simplicity and honesty which we admire in the works of the masters in number theory - Lagrange, Gauss, or on a smaller scale, Hardy, Landau. Just now Lang has published another book on algebraic numbers which, in my opinion, is still worse than the former one. I see a pig broken into a beautiful garden and rooting up all flowers and trees.
Unfortunately there are many "fellow-travellers" who have already disgraced a large part of algebra and function theory; however, until now, number theory had not been touched. These people remind me of the impudent behaviour of the national socialists who sang: "Wir werden weiter marschieren, bis alles in Scherben zerfällt!"
I am afraid that mathematics will perish before the end of this century if the present trend for senseless abstraction - as I call it: theory of the empty set - cannot be blocked up.