Regarding the sense of sight

 

Rudolf Steiner:

In the sixth sense, sight, it is the sentient soul that works on the etheric body and flows into it, but strange to say, this effect partakes of the nature of thought. It represents a mental principle, and the thoughts constitute the subconscious element of the process. The sentient soul subconsciously bears within it what the consciousness soul then raises to consciousness as thought. What flows out of the eyes is a thinking in the sentient soul. Real thought substance streams out of the eyes from the sentient soul. This thought substance has far greater elasticity than the other substances that flow out when the sense of smell or of taste is active. It can reach out much farther toward its objects — indeed, it is a fact that something of an astral substance streams forth from men to far distant objects, unchecked until some other astral element offers resistance.

The scientific explanation that in seeing, ether waves enter the eye and the latter then projects the image outward, can mean nothing to sound thinking. Somebody would have to be inside to work the projecting business, wouldn't he? What a horribly superstitious notion, this “Something that busily projects!” When in trouble, science, so proud of its “naturalism,” does not disdain the assistance of that “imagination” it professes to scorn.

It is something astral, then, thought substance, that flows toward the object. An astral element leaves the body, streams toward the object, and continues onward until opposed by another astral element. The conflict between these two astral elements engenders color, which we sense as pertaining to objects. Actually, the genesis of color occurs at the boundary of objects, where the astral element emanating from the human being collides with that of the object. Color comes into being where the inner and the outer astral elements meet.

Here spiritual science leads us to a strange phenomenon. We learned that really a kind of thinking resides in the sentient soul, but that its first appearance is in the intellectual soul and that it only becomes conscious in the consciousness soul. In the sentient soul it is subconscious. Now, when we look at an object with both eyes, we have two impressions that in the first instance do not reach our consciousness, although they originate in an unconscious thought process. Two mental efforts must be made, because we have two eyes. If we are to become conscious of these mental efforts, however, we must travel from the sentient soul by way of the mental soul to the consciousness soul. This path can be readily visualized by means of a simple analogy from the sense world. We have two hands and we feel each one individually, but if we wish this feeling to become conscious, that each hand should feel the other, they must touch each other, cross. If the impressions gained in the sentient soul through mental effort are to enter our consciousness, they must cross. In that way you feel your own hand; you render conscious what you ordinarily do not feel. Just as you must touch an external object to become conscious of it, so contact is here necessary if objects are to enter our consciousness. That is also the reason why the two optic nerves in the physical brain are crossed. Through this crossing, an effort made subconsciously in the sentient soul is raised into the consciousness soul; one effort can be sensed by means of the other. That is an illustration of the way anthroposophy teaches us to know the human being down to the most intricate anatomical details.

Source: October 25, 1909