Josiah Royce,
The World and the Individual, First Series
(1899)
“ The mathematician builds up these his objects, as, for instance, the objects of pure Analysis, very much as he pleases. His ideas are in so far his facts. So far one would suppose, then, that no questions about existence would trouble the mathematician. But when one looks closer, one sees that when the mathematician has once built up such a notion of some realm of ideal objects, there may then arise the further question whether, within that realm, an object that meets certain new requirements, the special requirements, let us say, of a given problem, can be found or not. ”
