while man was involved by his animal
nature in the accidents of experience he was also by virtue of his
rationality a participator in eternal truth. A substantial justice was
thus done both to the conditions and to the functions of human life,
although, for want of a natural history inspired by mechanical ideas,
this dualism remained somewhat baffling and incomprehensible in its
basis. Aristotle, being a true philosopher and pupil of experience,
preferred incoherence to partiality.

[Sidenote: Empirical bias in favour of contiguity.]

Active life and the philosophy that borrows its concepts from practice
has thus laid a great emphasis on association by contiguity. Hobbes and
Locke made knowledge of this kind the only knowledge of reality, while
recognising it to be quite empirical, tentative, and problematical. It
was a kind of acquaintance with fact that increased with years and
brought the mind into harmony with something initially alien to it.
Besides this practical knowledge or prudence there was a sort of verbal
and merely ideal knowledge, a knowledge of the meaning and relation of
abstract terms. In mathematics and logic we might carry out long trains
of abstracted thought and analyse and develop our imaginations _ad
infinitum_. These speculations, however, were in the air or--what for
these philosophers is much the same thing--in the mind; their
applicability and their relevance to practical life and to objects given
in perception remained quite problematical. A self-developing science, a
synthetic science _a priori_, had a value entirely hypothetical and
provisional; its practical truth depended on the verification of its
results in some eventual sensible experience. Association was invoked to
explain the adjustment of ideation to the order of external perception.
Association, by which association by contiguity was generally
understood, thus became the battle-cry of empiricism; if association by
similarity had been equally in mind, the philosophy of pregnant reason
could also have adopted the principle for its own. But logicians and
mathematicians naturally neglect the psychology of their own processes
and, accustomed as they are to an irresponsible and constructive use of
the intellect, regard as a confused and uninspired intruder the critic
who, by a retrospective and naturalistic method, tries to give them a
little knowledge of themselves.

[Sidenote: Artificial divorce of logic from practice.]

Rational