_two_, or at least, between _one_ and _many_.

These facts must of necessity deter the mathematician from seeking to push
his investigation too far back toward the very origin of number.
Philosophers have endeavoured to establish certain propositions concerning
this subject, but, as might have been expected, have failed to reach any
common ground of agreement. Whewell has maintained that "such propositions
as that two and three make five are necessary truths, containing in them an
element of certainty beyond that which mere experience can give." Mill, on
the other hand, argues that any such statement merely expresses a truth
derived from early and constant experience; and in this view he is heartily
supported by Tylor.[3] But why this question should provoke controversy, it
is difficult for the mathematician to understand. Either view would seem to
be correct, according to the standpoint from which the question is
approached. We know of no language in which the suggestion of number does
not appear, and we must admit that the words which give expression to the
number sense would be among the early words to be formed in any language.
They express ideas which are, at first, wholly concrete, which are of the
greatest possible simplicity, and which seem in many ways to be clearly
understood, even by the higher orders of the brute creation. The origin of
number would in itself, then, appear to lie beyond the proper limits of
inquiry; and the primitive conception of number to be fundamental with
human thought.

In connection with the assertion that the idea of number seems to be
understood by the higher orders of animals, the following brief quotation
from a paper by Sir John Lubbock may not be out of place: "Leroy ...
mentions a case in which a man was anxious to shoot a crow. 'To deceive
this suspicious bird, the plan was hit upon of sending two men to the watch
house, one of whom passed on, while the other remained; but the crow