Pressure, of
Equilibrium of the body, and a host of peculiar sensational conditions
which, for all we know, may be separate and distinct, or may arise
from combinations of some of the others. Such, for example, are the
sensations which are felt when a current of electricity is sent
through the arm.

All these give the mind its material to work upon; and it gets no
material in the first instance from any other source. All the things
we know, all our opinions, knowledges, beliefs, are absolutely
dependent at the start upon this supply of material from our senses;
although, as we shall see, the mind gets a long way from its first
subjection to this avalanche of sensations which come constantly
pouring in upon it from the external world. Yet this is the essential
and capital function of Sensation: to supply the material on which the
mind does the work in its subsequent thought and action.

Next comes the process by which the mind holds its material for future
use, the process of Memory; and with it the process by which it
combines its material together in various useful forms, making up
things and persons out of the material which has been received and
remembered--called Association of Ideas, Thinking, Reasoning, etc. All
these processes used to be considered as separate "faculties" of the
soul and as showing the mind doing different things. But that view is
now completely given up. Psychology now treats the activity of the
mind in a much more simple way. It says: Mind does only one thing; in
all these so-called faculties we have the mind doing this one thing
only on the different materials which come and go in it. This one
thing is the combining, or holding together, of the elements which
first come to it as sensations, so that it can act on a group of them
as if they were only one and represented only one external thing. Let
me illustrate this single and peculiar sort of process as it goes on
in the mind.

We may ask how the child apprehends an orange out there on the table
before him. It can not be said that the orange goes into the child's
mind by any one of its senses. By sight he gets only the colour and
shape of the orange, by smell he gets only its odour, by taste its
sweetness, and by touch its smoothness, rotundity, etc. Furthermore,
by none of these senses does he find out the individuality of the
orange, or distinguish it from other things which involve the same or
similar sensations--say an apple. It is ea