seen from without,
but is superadded, by the action of the mind, to motionless pictures.

The statement that our impression of movement does not result simply
from the seeing of successive stages but includes a higher mental act
into which the successive visual impressions enter merely as factors is
in itself not really an explanation. We have not settled by it the
nature of that higher central process. But it is enough for us to see
that the impression of the continuity of the motion results from a
complex mental process by which the various pictures are held together
in the unity of a higher act. Nothing can characterize the situation
more clearly than the fact which has been demonstrated by many
experiments, namely, that this feeling of movement is in no way
interfered with by the distinct consciousness that important phases of
the movement are lacking. On the contrary, under certain circumstances
we become still more fully aware of this apparent motion created by our
inner activity when we are conscious of the interruptions between the
various phases of movement.

We come to the consequences. What is then the difference between seeing
motion in the photoplay and seeing it on the real stage? There on the
stage where the actors move the eye really receives a continuous series.
Each position goes over into the next without any interruption. The
spectator receives everything from without and the whole movement which
he sees is actually going on in the world of space without and
accordingly in his eye. But if he faces the film world, _the motion
which he sees appears to be a true motion, and yet is created by his own
mind_. The afterimages of the successive pictures are not sufficient to
produce a substitute for the continuous outer stimulation; the essential
condition is rather the inner mental activity which unites the separate
phases in the idea of connected action. Thus we have reached the exact
counterpart of our results when we analyzed the perception of depth. We
see actual depth in the pictures, and yet we are every instant aware
that it is not real depth and that the persons are not really plastic.
It is only a suggestion of depth, a depth created by our own activity,
but not actually seen, because essential conditions for the true
perception of depth are lacking. Now we find that the movement too is
perceived but that the eye does not receive the impressions of true
movement. It is only a suggestion of movemen