and the motions in consequence of this new faculty
of the sensorium are called voluntary.

I. 1. Those muscles of the body that are attached to bones, have in general
their principal connections with volition, as I move my pen or raise my
body. These motions were originally excited by irritation, as was explained
in the section on that subject, afterwards the sensations of pleasure or
pain, that accompanied the motions thus excited, induced a repetition of
them; and at length many of them were voluntarily practised in succession
or in combination for the common purposes of life, as in learning to walk,
or to speak; and are performed with strength and velocity in proportion to
the energy of the volition, that excites them, and the quantity of
sensorial power.

2. Another great class of voluntary motions consists of the ideas of
recollection. We will to repeat a certain train of ideas, as of the
alphabet backwards; and if any ideas, that do not belong to this intended
train, intrude themselves by other connections, we will to reject them, and
voluntarily persist in the determined train. So at my approach to a house
which I have but once visited, and that at the distance of many months, I
will to recollect the names of the numerous family I expect to see there,
and I do recollect them.

On this voluntary recollection of ideas our faculty of reason depends, as
it enables us to acquire an idea of the dissimilitude of any two ideas.
Thus if you voluntarily produce the idea of a right-angled triangle, and
then of a square; and after having excited these ideas repeatedly, you
excite the idea of their difference, which is that of another right-angled
triangle inverted over the former; you are said to reason upon this
subject, or to compare your ideas.

These ideas of recollection, like the muscular motions above mentioned,
were originally excited by the irritation of external bodies, and were
termed ideas of perception: afterwards the pleasure or pain, that
accompanied these motions, induced a repetition of them in the absence of
the external body, by which they were first excited; and then they were
termed ideas of imagination. At length they become voluntarily practised in
succession or in combination for the common purposes of life; as when we
make ourselves masters of the history of mankind, or of the sciences they
have investigated; and are then called ideas of recollection; and are
performed with strength and velocity