384. Since all things of the mind have relation to the will and understanding and all things of the body to the heart and lungs so there are in the head two brains, each distinct from the other as is the case with the will and understanding. The cerebellum exists chiefly for the sake of the will, and the cerebrum chiefly for the understanding. Similarly the heart and lungs in the body are distinct from the rest of the organs there. They are separated from them by the diaphragm and are enveloped by a covering of their own, called the pleura, and form that part of the body called the chest. In the other parts of the body, that is, the members, organs and viscera, the will and the understanding are joined together, and thus also there are pairs; for example, arms, hands, loins, feet, eyes, nostrils; within the body, kidneys, ureters, testicles; and the viscera, which are not in pairs, are divided into right and left. Moreover, the brain itself is divided into two hemispheres, the heart into two ventricles, and the lungs into two lobes. The right of these relates to the goodness belonging to truth, and the left to the truth belonging to goodness; or what is the same, the right has relation to the goodness of love from which comes the truth of wisdom, and the left to the truth of wisdom which comes from the good of love. And because the union of good and truth is reciprocal, and by means of that union they become as it were one, the effect in man is that these pairs act together and jointly in their functions, movements, and sensations.