termed complex ideas by the writers of metaphysics, as this book, or that
orange. The trains have received no particular name, but these are alike
associations of ideas, and frequently continue during our lives. So the
taste of a pine-apple, though we eat it blindfold, recalls the colour and
shape of it; and we can scarcely think on solidity without figure.

II. 1. By the various efforts of our sensations to acquire or avoid their
objects, many muscles are daily brought into successive or synchronous
actions; these become associated by habit, and are then excited together
with great facility, and in many instances gain indissoluble connections.
So the play of puppies and kittens is a representation of their mode of
fighting or of taking their prey; and the motions of the muscles necessary
for those purposes become associated by habit, and gain a great adroitness
of action by these early repetitions: so the motions of the abdominal
muscles, which were originally brought into concurrent action, with the
protrusive motion of the rectum or bladder by sensation, become so
conjoined with them by habit, that they not only easily obey these
sensations occasioned by the stimulus of the excrement and urine, but are
brought into violent and unrestrainable action in the strangury and
tenesmus. This kind of connection we shall term sensitive association.

2. So many of our ideas, that have been excited together or in succession
by our sensations, gain synchronous or successive associations, that are
sometimes indissoluble but with life. Hence the idea of an inhuman or
dishonourable action perpetually calls up before us the idea of the wretch
that was guilty of it. And hence those unconquerable antipathies are
formed, which some people have to the sight of peculiar kinds of food, of
which in their infancy they have eaten to excess or by constraint.

III. 1. In learning any mechanic art, as music, dancing, or the use of the