Authors:
  • Your discovery of the contradiction caused me the greatest surprise and, I would almost say, consternation, since it has shaken the basis on which I intended to build my arithmetic.

    "From Frege to Godel: A Source Book in Mathematical Logic, 1879-1931". Book edited by J. van Heijenoort, "Letter to Bertrand Russel" (1902), 1967.