Either world means the spiritual and natural worlds. In the spiritual world these spheres meet in the world of spirits, because this is midway between heaven and hell. But in the natural world they meet at the level of a person's reason, since this too is midway between heaven and hell. For the marriage of good and truth exerts an influence on it from above, and the marriage of evil and falsity does the same from below. This influence comes through the world, the other through heaven, so that the human faculty of reason can turn in either direction and receive the influence. If it turns towards good, it receives the influence from above, which makes it more and more attuned to the reception of heaven. But if it turns towards evil, it receives the influence from below, which makes it more and more attuned to the reception of hell.

[2] The two spheres cannot join because they are opposites, and one opposite can only act on another as an enemy, one of whom blazing with murderous hatred furiously attacks the other, though the other feels no hatred, but is only zealous to protect himself. These facts make it plain that these two spheres merely meet, but without joining. The intervening gap they leave is on one side from evil, which is not that of falsity and from falsity which is not that of evil, and on the other side from good which is not that of truth and from truth which is not that of good. These pairs can come into contact, but cannot join.