acts in the two cases provided that there is nothing in the one case
to compel or in the other to prevent. Again, I ought to create a good,
a house is good: straightway I make a house. I need a covering, a coat
is a covering: I need a coat. What I need I ought to make, I need a
coat: I make a coat. And the conclusion I must make a coat is an
action. And the action goes back to the beginning or first step. If
there is to be a coat, one must first have B, and if B then A, so
one gets A to begin with. Now that the action is the conclusion is
clear. But the premisses of action are of two kinds, of the good and
of the possible.
And as in some cases of speculative inquiry we suppress one
premise so here the mind does not stop to consider at all an obvious
minor premise; for example if walking is good for man, one does not
dwell upon the minor 'I am a man'. And so what we do without
reflection, we do quickly. For when a man actualizes himself in
relation to his object either by perceiving, or imagining or
conceiving it, what he desires he does at once. For the actualizing of
desire is a substitute for inquiry or reflection. I want to drink,
says appetite; this is drink, says sense or imagination or mind:
straightway I drink. In this way living creatures are impelled to move
and to act, and desire is the last or immediate cause of movement, and
desire arises after perception or after imagination and conception.
And things that desire to act now create and now act under the
influence of appetite or impulse or of desire or wish.
The movements of animals may be compared with those of automatic
puppets, which are set going on the occasion of a tiny movement; the
levers are released, and strike the twisted strings against one
another; or with the toy wagon. For the child mounts on it and moves
it straight forward, and then again it is moved in a circle owing to
its wheels being of unequal diameter (the smaller acts like a centre
on the same principle as the cylinders). Animals have parts of a
similar kind, their organs, the sinewy tendons to wit and the bones;