De Motu Animalium, Chapter 7 by Aristotle
(translated by A. S. L. Farquharson)
But how is it that thought (viz. sense, imagination, and thought proper)
is sometimes followed by action, sometimes not; sometimes by movement,
sometimes not? What happens seems parallel to the case of thinking and
inferring about the immovable objects of science. There the end is the
truth seen (for, when one conceives the two premisses, one at once
conceives and comprehends the conclusion), but here the two premisses
result in a conclusion which is an action- for example, one conceives that
every man ought to walk, one is a man oneself: straightway one walks; or
that, in this case, no man should walk, one is a man: straightway one
remains at rest. And one so 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.
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