It was necessary to find such structure in a brain which would be at the same time uniform and only (that is would not have divisions and it would not be duplicated in each of hemispheres a brain. Such structure — from the point of view of Descartes — is the shishkovidny body or sopapit. He also declared this brain body the meeting place of soul and a body.
Descartes's position fits into a framework of more general movement considering behavior of the person as the determined, predictable process. All movements or actions of a mechanical body can be predicted in advance if the inducing incentives are known.
Descartes describes this interaction in typically mechanistic manner: the animal juice moving on nervous tubes is imprinted in an way in a shishkovidny body, and on this basis mind creates sensual images, perceptions. In other words, a movement (the flow of animals of juice will create sincere quality (perception. Fairly and the return: mind somehow itself in a shishkovidny body (not absolutely clearly, however, as it ), and the last, in turn, deviating in this or that party, directs currents of animal juice to these or those muscles of a body. The physical movement results. Thus the condition of the person causes the physical movements peculiar to his body.
The mind however conceiving, feeling and having free will has to influence somehow a body and perceive responses. If intention, for example, to move from one place to another is born in the soul, this desire is carried out by muscles, sinews and nerves of our body. Similarly, if the body is affected by any incentive (light or heat, for example), mind perceives and processes sensual data and makes the decision on the corresponding reaction.