In our theory the total field of excitation is divided into two major sub-systems, each containing numerous sub-systems of its own: the Ego and the e… - Kurt Koffka

Things look as they do because of the field organization to which the proximal stimulus distribution gives rise. This answer is final and can be so only because it contains the whole problem of organization itself.

If an environmental trace is in close connection with the Ego system it will not only be in communication with the particular time structure of that system with which it communicated at the time of its formation; but because of the coherence of the whole temporal Ego system it will be in communication with later strata also.

The second factor, equally important, is that of good continuation and good shape. The things which we see have a better shape, are bounded by better contours, than the holes which we might see but do not. Therefore, when in exceptional circumstances these conditions are reversed, we see the hole and not the things, as the shape of a gap between two projecting rocks with sharp profiles, which may look like a face, an animal, or some other object, while the shape of the rock disappears.