All knowledge must be recognition, on pain of being mere delusion; Arithmetic must be discovered in just the same sense in which Columbus discovered the West Indies, and we no more create numbers than he created the Indians... Whatever can be thought of has being and its [arithmetic] being is a precondition, not a result, of its being thought of.
Is Position in Space and Time Absolute or Relative - Mind, Volume X, 1901 (p. 312)