Hubbard and Hubbard (in "Vector Calculus...") attribute the following quote to Felix Klein: "Everyone knows what a curve is, until he has studied enough mathematics to become confused through the countless number of possible exceptions."

Does anyone know where this comes from? I'd be interested in the original German text.


2 Answers 2


Elementarmathematik vom höheren Standpunkte aus, Bd.2

Was eine Kurve ist, glaubt jeder Mensch zu wissen, bis er so viel Mathematik gelernt hat, daß ihn die unzähligen möglichen Abnormitäten verwirrt gemacht haben.

see also Quotations by Felix Klein for the English version.


In Gert Schubring's translation from 2016, the exact statement is: "Every person believes that he knows what a curve is until he has learned so much mathematics that the countless possible abnormalities confuse him." (p. 199).


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.