The Complete Aristotle (eng.)

therefore, that in all locomotion there is nothing
intermediate between moved and movent.
    Nor again is there anything intermediate between that which
undergoes and that which causes alteration: this can be proved by
induction: for in every case we find that the respective
extremities of that which causes and that which undergoes
alteration are adjacent. For our assumption is that things that are
undergoing alteration are altered in virtue of their being affected
in respect of their so-called affective qualities, since that which
is of a certain quality is altered in so far as it is sensible, and
the characteristics in which bodies differ from one another are
sensible characteristics: for every body differs from another in
possessing a greater or lesser number of sensible characteristics
or in possessing the same sensible characteristics in a greater or
lesser degree. But the alteration of that which undergoes
alteration is also caused by the above-mentioned characteristics,
which are affections of some particular underlying quality. Thus we
say that a thing is altered by becoming hot or sweet or thick or
dry or white: and we make these assertions alike of what is
inanimate and of what is animate, and further, where animate things
are in question, we make them both of the parts that have no power
of sense-perception and of the senses themselves. For in a way even
the senses undergo alteration, since the active sense is a motion
through the body in the course of which the sense is affected in a
certain way. We see, then, that the animate is capable of every
kind of alteration of which the inanimate is capable: but the
inanimate is not capable of every kind of alteration of which the
animate is capable, since it is not capable of alteration in
respect of the senses: moreover the inanimate is unconscious of
being affected by alteration, whereas the animate is conscious of
it, though there is nothing to prevent the animate also being
unconscious of it when the process of the alteration does not
concern the senses. Since, then, the alteration of that which
undergoes alteration is caused by sensible things, in every case of
such alteration it is evident that the respective extremities of
that which causes and that which undergoes alteration are adjacent.
Thus the air is continuous with that which causes the alteration,
and the body that undergoes alteration is continuous with the air.
Again, the colour is continuous with the light and the light with
the sight. And the same is true of hearing and smelling: for the
primary movent in respect to the moved is the air. Similarly, in
the case of tasting, the flavour is adjacent to the sense of taste.
And it is just the same in the case of things that are inanimate
and incapable of sense-perception. Thus there can be nothing
intermediate between that which undergoes and that which causes
alteration.
    Nor, again, can there be anything intermediate between that
which suffers and that which causes increase: for the part of the
latter that starts the increase does so by becoming attached in
such a way to the former that the whole becomes one. Again, the
decrease of that which suffers decrease is caused by a part of the
thing becoming detached. So that which causes increase and that
which causes decrease must be continuous with that which suffers
increase and that which suffers decrease respectively: and if two
things are continuous with one another there can be nothing
intermediate between them.
    It is evident, therefore, that between the extremities of the
moved and the movent that are respectively first and last in
reference to the moved there is nothing intermediate.
<
    div id="section59" class="section" title="3">
3
    Everything, we say, that undergoes alteration is altered by
sensible causes, and there is alteration only in things that are
said to be essentially affected by sensible things. The truth of
this is to be seen from the following considerations. Of all other
things it would be most natural to suppose that there is alteration
in figures and shapes, and in acquired states and in the processes
of acquiring and losing these: but as a matter of fact in neither
of these two classes of things is there alteration.
    In the first place, when a particular formation of a thing is
completed, we do not call it by the name of its material: e.g. we
do not call the statue ‘bronze’ or the pyramid ‘wax’ or the bed
‘wood’, but we use a derived expression and call them ‘of