Even stranger things have happened; and perhaps the strangest of all is the marvel that mathematics should be possible to a race akin to the apes.

Time makes fools of us all. Our only comfort is that greater shall come after us.

Wherever groups disclosed themselves, or could be introduced, simplicity crystallized out of comparative chaos.

I have always hated machinery, and the only machine I ever understood was a wheelbarrow, and that but imperfectly.

It is the perennial youthfulness of mathematics itself which marks it off with a disconcerting immortality from the other sciences.

Obvious is the most dangerous word in mathematics.

The full impact of the Lobachevskian method of challenging axioms has probably yet to be felt. It is no exaggeration to call Lobachevsky the Copernicus of Geometry [as did Clifford], for geometry is only a part of the vaster domain which he renovated; it might even be just to designate him as a Copernicus of all thought.