Chapter IX (part 1)

p. 98 CHAPTER IX The receptivity of the world by a man and by an animal. Illusions of the animal and its lack of control of the receptive faculties. The world of moving planes. Angles and curves considered as motion. The third dimension as motion. The animal's two-dimensional view of our three-dimensional world. The animal as a real two-dimensional being. Lower animals as one-dimensional beings. The time and space of a snail. The time-sense as an imperfect space-sense. The time and space of a dog. The change in the world coincident with a change in the psychic apparatus. The proof of Kant's problem. The three-dimensional world—an illusionary perception. WE have established the enormous difference existing between the psychology of a man and of an animal. This difference undoubtedly profoundly affects the receptivity of the outer world by the animal. But how and in what? This is exactly what we do not know, and what we shall try to discover. To this end we shall return to our receptivity of the world, investigate in detail the nature of that receptivity, and then imagine how the animal, with its more limited psychic equipment, receives its impression of the world. Let us note first of all that we receive the most incorrect impressions of the world as regards its outer form and aspect. We know that the world consists of solids, but we see and touch only surfaces . We never see and touch a solid . The solid—this is indeed a concept , composed of a series of perceptions, the result of reasoning and experience. For immediate sensation, surfaces alone exist. Sensations of gravity, mass, volume, which we mentally associate with the "solid," are in reality associated with the sensations of surfaces. We only know that the sensation comes from the solid, but the solid itself we never sense. Perhaps it would be possible to call the complex sensation of surfaces: weight, mass, density, resistance, "the sensation of a solid," but rather do we combine mentally all these sensations into one, and call that composite sensation a solid. We sense directly only surfaces; the weight and resistance of the solid, as such, we never separately sense. p. 99 But we know that the world does not consist of surfaces: we know that we see the world incorrectly, and that we never see it as it is , not alone in the philosophical meaning of the expression, but in the most simple geometrical meaning. We have never seen a cube, a sphere , etc., but only their surfaces. Knowing this, we mentally correct that which we see. Behind the surfaces we think the solid. But we can never even represent the solid to ourselves. We cannot imagine the cube or the sphere seen, not in perspective, but simultaneously from all sides. It is clear that the world does not exist in perspective; nevertheless we cannot see it otherwise. We see everything only in perspective; that is, in the very act of receptivity the world is distorted in our eye, and we know that it is distorted. We know that it is not such as it appears, and mentally we are continuously correcting that which the eye sees, substituting the real content for those symbols of things which sight reveals. Our sight is a complex faculty. It consists of visual sensations plus the memory of sensations of touch. The child tries to feel with its finger-tips everything that it sees—the nose of its nurse, the moon, the reflection of sun rays from the mirror on the wall. Only gradually does it learn to discern the near and the distant by means of sight alone . But we know that even in mature age we are easily subject to optical illusions. We see distant objects as flat, even more incorrectly, because relief is after all a symbol revealing a certain property of objects. A man at a long distance is pictured to us in silhouette.