ABSTRACT
The step in the evolution of animals is the neurulation, the occurrence of the neural tube, the beginning of the central nervous system (CNS), on the back of the gastrula. Neurulation is of specific importance to biosemiotics. A main source of our human inner life, the soul, is mediated through this inner sign system. Gastrulation is the base of the animal body; neurulation, the base of the animal soul. One can observe this in all forms of deuterostomia without neurulation. The principle of subjectivity manifests itself as life in the inner system of cells, becomes body and experience in the gastrular organization and results in the neural system as soul, separated from the physical outer system. A specific neural ability is the development of a space model that helps one to put into place the perceptions of reality.
