Human Individuality 99mechanical process of motion, forget that they are merely
passing from one percept to another and not at all to
something outside perception. Just as we can say that the
eye perceives a mechanical process of motion in its envi-
ronment as light, so we could just as well claim that any
systematic change in an object is perceived by us as a pro-
cess of motion. If I draw twelve pictures of a horse on the
circumference of a rotating disc, in exactly the positions
that its body assumes in the course of a gallop, then I can
by rotating the disc evoke the illusion of movement. I
need only look through an opening in such a way that I see
the successive positions of the horse at appropriate inter-
vals. Then I see, not twelve pictures of a horse, but the im-
age of a single horse galloping.
Thus, the physiological fact mentioned above can
throw no light on the relation of percepts to mental pic-
tures. We must find our way by some other means.
The moment a percept emerges on the horizon of my
observation, thinking, too, is activated in me. An element
of my thought-system—a specific intuition, a concept—
unites with the percept. Then, when the percept disap-
pears from my field of vision, what remains? What re-
mains is my intuition, with its relationship to the specific
percept that formed in the moment of perceiving. How
vividly I can then later re-present this relationship to my-
self depends upon how my spiritual and bodily organism
is functioning. A mental picture is nothing but an intu-
ition related to a specific percept. It is a concept, once
linked to a percept, for which the relation to that percept
has remained. My concept of a lion is not formedout of