Oskar Morgenstern, " Limits of the Use of Mathematics in Economics https://www.princeton.edu/~erp/ERParchives/archivepdfs/M49.pdf," in: James C. Charlesworth (Hg.), Mathematics and the Social Science. The Utility and Inutility of Mathematics in the Study of Economics, Political Sciences and Sociology, Philadelphia 1963, S. 12-29, hier S. 18.
“A mathematical problem should be difficult in order to entice us, yet not completely inaccessible, lest it mock at our efforts.”
Mathematical Problems (1900)
Context: A mathematical problem should be difficult in order to entice us, yet not completely inaccessible, lest it mock at our efforts. It should be to us a guide post on the mazy paths to hidden truths, and ultimately a reminder of our pleasure in the successful solution.
Help us to complete the source, original and additional information
David Hilbert 30
German prominent mathematician 1862–1943Related quotes

As quoted in The World of Mathematics (1956) Edited by J. R. Newman

Twitter - About the Muhammad Art Contest in Texas at 1st May, 2015 https://twitter.com/realDonaldTrump/status/595406508378173440 (4 May 2015)
2010s, 2015

Entry (1951)
Eric Hoffer and the Art of the Notebook (2005)

As quoted in "The Mathematician" in The World of Mathematics (1956), by James Roy Newman