At first sight it might seem an idle observation that the first task of
intelligence is to represent the environing reality, a reality actually
represented in the notion, universally prevalent among men, of a cosmos
in space and time, an animated material engine called nature. In trying
to conceive nature the mind lisps its first lesson; natural phenomena
are the mother tongue of imagination no less than of science and
practical life. Men and gods are not conceivable otherwise than as
inhabitants of nature. Early experience knows no mystery which is not
somehow rooted in transformations of the natural world, and fancy can
build no hope which would not be expressible there. But we are grown so
accustomed to this ancient apparition that we may be no longer aware how
difficult was the task of conjuring it up. We may even have forgotten
the possibility that such a vision should never have arisen at all. A
brief excursion into that much abused subject, the psychology of
perception, may here serve to remind us of the great work which the
budding intellect must long ago have accomplished unawares.

[Sidenote: Difficulties in conceiving nature.]

Consider how the shocks out of which the notion of material things is to
be built first strike home into the soul. Eye and hand, if we may
neglect the other senses, transmit their successive impressions, all
varying with the position of outer objects and with the other material
conditions. A chaos of multitudinous impressions rains in from all sides
at all hours. Nor have the external or cognitive senses an original
primacy. The taste, the smell, the alarming sounds of things are
continually distracting attention. There are infinite reverberations in
memory of all former impressions, together with fresh fancies created in
the brain, things at first in no wise subordinated to external objects.