tion upon knowledge of
three-dimensional existence, because, before proceeding to the
relations of Subject and Form in painting, I want to impress once
more upon the reader the distinction between the _locomotion of
things_ (locomotion active or passive) and what, in my example of
the _mountain which rises,_ I have called the _empathic movement
of lines._ Such _movement of lines_ we have seen to be a scheme of
activity suggested by our own activity in taking stock of a
two-dimensional-shape; an _idea,_ or _feeling_ of activity which we,
being normally unaware of its origin in ourselves, project into the
shape which has suggested it, precisely as we project our sensation
of _red_ from our own eye and mind into the object which has
deflected the rays of light in such a way as to give us that _red_
sensation. Such _empathic,_ attributed, movements of lines are
therefore intrinsic qualities of the shapes whose active perception
has called them forth in our imagination and feeling; and being
qualities of the shapes, they inevitably change with every alteration
which a shape undergoes, every shape, actively perceived, having its
own special _movement of lines;_ and every _movement of lines,_
or _combination of movements of lines_ existing in proportion as
we go over and over again the particular shape of which it is a
quality. The case is absolutely reversed when we perceive or think
of, the _locomotion of things._ The thought of a thing's locomotion,
whether locomotion done by itself or inflicted by something else,
necessitates our thinking away from the particular shape before us to
another shape more or less different. In other words locomotion
necessarily alters what we are looking at or thinking of. If we think
of Michel Angelo's seated Moses as getting up, we think _away_
from the approximately pyramidal shape of the statue to the
elongated oblong of a standing figure. If we think of the horse of
Marcus Aurelius as taking the next step, we think of a straightened
leg set on the ground instead of a curved leg suspended in the air.
And if we think of the Myronian Discobolus as letting go his quoit
and "recovering," we think of the matchless spiral composition as
unwinding and straightening itself into a shape as different as that of
a tree is different from that of a shell.

The pictorial representation of locomotion affords therefore the
extreme example of the difference between discursive thinking
about things and con