their order. Reason, however, intervenes. Its process is well known. In
every object of perception, as it exists in the physical world and is
given by sensation to our consciousness, there is both in itself and in
its relations a likeness to other objects and relations, and this
likeness the mind takes notice of; it thus analyzes the complex of
experience, discerns the common element, and by this means classifies
particular facts, thereby condensing them into mental conceptions,--
abstract ideas, formulas, laws. The mind arrives at these in the
course of its normal operation. As soon as we think at all, we speak
of white and black, of bird and beast, of distance and size,--of
uniformities in the behaviour of nature, or laws; by such classification
of qualities, objects, and various relations, not merely in the sensuous
but in every sphere of our consciousness, the mind simplifies its
experience, compacts its knowledge, and economizes its energies. To this
work it brings, also, the method of experiment. It then interferes
arbitrarily with the natural occurrence of facts, and brings that to
pass which otherwise would not have been; and this method it uses to
investigate, to illustrate what was previously known, and to confirm
what was surmised. Its end, whether through observation or experiment,
is to reach general truth as opposed to matter-of-fact, universals more
or less embracing as opposed to particulars, the units of thought as
opposed to the units of phenomena. The body of these constitutes
rational knowledge.

Nature then becomes known, not as a series of impressions on the retina
of sense merely, but as a system seized by the eye of reason; for the
senses show man the aspect worn by the world as it is at the moment, but
reason opens to him the order obtaining in the world as it must be at
every moment; and the instrument by which man rises from the phenomenal
plane of experience to the necessary sphere of truth is the generalizing