600. It must be understood that the conjunction of man with heaven and with hell is not a direct conjunction with them, but a mediate conjunction by means of spirits who are in the world of spirits. These spirits, and none from hell itself or from heaven itself, are with man. By means of evil spirits in the world of spirits man is conjoined with hell, and by means of good spirits there he is conjoined with heaven. Because of this the world of spirits is intermediate between heaven and hell, and in that world is equilibrium itself. (That the world of spirits is intermediate between heaven and hell may be seen in the chapter on the world of spirits, n. 421-431; and that the essential equilibrium between heaven and hell is there may be seen in the preceding chapter, n. 589-596.) From all this the source of man's freedom is evident.