This sense is very highly developed in us, and the earlier period of our
existence is largely given over to feeling for the objective world
outside ourselves. Who has not watched the little baby hands feeling for
everything within reach, and without its reach, for the matter of that;
for the infant has no knowledge yet of what is and what is not within
its reach. Who has not offered some bright object to a young child and
watched its clumsy attempts to feel for it, almost as clumsy at first as
if it were blind, as it has not yet learned to focus distances. And when
he has at last got hold of it, how eagerly he feels it all over, looking
intently at it all the time; thus learning early to associate the "feel
of an object" with its appearance. In this way by degrees he acquires
those ideas of roughness and smoothness, hardness and softness,
solidity, &c., which later on he will be able to distinguish by vision
alone, and without touching the object.

Our survival depends so much on this sense of touch, that it is of the
first importance to us. We must know whether the ground is hard enough
for us to walk on, or whether there is a hole in front of us; and masses
of colour rays striking the retina, which is what vision amounts to,
will not of themselves tell us. But associated with the knowledge
accumulated in our early years, by connecting touch with sight, we do
know when certain combinations of colour rays strike the eye that there
is a road for us to walk on, and that when certain other combinations
occur there is a hole in front of us, or the edge of a precipice.

And likewise with hardness and softness, the child who strikes his head
against the bed-post is forcibly reminded by nature that such things are
to be avoided, and feeling that it is hard and that hardness has a
certain look, it avoids that kind of thing in the future. And when it