Today the mathematician admits the existence and the necessity of many theories, many geometries, each appealing to certain interests, each to be developed by the most appropriate methods; and he realizes that, no matter how large his conceptions and how powerful his methods, they will be replaced before long by others larger and more powerful.

The Present Problems of Geometry, Bulletin of the American Mathematical Society, Volume XI, Number 6, March, 1905 (p. 283)