The vertical division between the voluntary and the sympathetic systems, the line of division between the spinal system and the great plexus-system of the front of the human body, forms the second distinction into duality. It is the great difference between the soft, recipient front of the body and the wall of the back. The front of the body is the live end of the magnet. The back is the closed opposition. And again there are two parallel streams of function and consciousness, vertically separate now. This is the vertical line of division. And the horizontal line and the vertical line form the cross of all existence and being. And even this is not mysticism—no more than the ancient symbols used in botany or biology. On the first field of human consciousness, which is the basis of life and consciousness, are the four first poles of spontaneity. These have their fourfold polarity within the individual, again figured by the cross. But the individual is never purely a thing-by-himself. He cannot exist save in polarized relation to the external universe, a relation both functional and psychic-dynamic. Development takes place only from the polarized circuits of the dynamic unconscious, and these circuits must be both individual and extra-individual. There must be the circuit of which the complementary pole is external to the individual. That is, in the first place there must be the _other individual_. There must be a polarized connection with the other individual—or even other individuals. On the first field there are four poles in each individual. So that the first, the basic field of extra-individual consciousness contains eight poles—an eightfold polarity, a fourfold circuit. It may be that between two individuals, even mother and child, the polarity may be established only fourfold, a dual circuit. It may be that one circuit of spontaneous consciousness may never be fully established. This means, for a child, a certain deficiency in development, a psychic inadequacy. So we are again face to face with the basic problem of human conduct. No human being can develop save through the polarized connection with other beings. This circuit of polarized unison precedes all mind and all knowing. It is anterior to and ascendant over the human will. And yet the mind and the will can both interfere with the dynamic circuit, an idea, like a stone wedged in a delicate machine, can arrest one whole process of psychic interaction and spontaneous growth.