I turn away with fright and horror from the lamentable evil of functions which do not have derivatives.

We are servants rather than masters in mathematics.

Analysis takes back with one hand what it gives with the other. I recoil in fear and loathing from that deplorable evil: continuous functions with no derivatives.

I shall risk nothing on an attempt to prove the transcendence of p. If others undertake this enterprise, no one will be happier than I in their success. But believe me, it will not fail to cost them some effort.

Abel has left mathematicians something to keep them busy for five hundred years.

I believe that numbers and functions of Analysis are not the arbitrary result of our minds; I think that they exist outside of us, with the same character of necessity as the things of objective reality, and we meet them or discover them, and study them, as do the physicists, the chemists and the zoologists.

I turn away with fright and horror from the lamentable evil of functions which do not have derivatives.