446. The deepest communication of our spirit is with our breathing and our heartbeat; thought connects with our breathing, and affection, an attribute of love, with our heart. ¹ Consequently, when these two motions in the body cease, there is an immediate separation. It is these two motions, the respiratory motion of the lungs and the systolic motion of the heart, that are essential ties. Once they are severed, the spirit is left to itself; and the body, being now without the life of its spirit, cools and decays.

The reason the deepest communication of our spirit is with our breathing and our heart is that all our vital processes depend on these, not only in a general way, but in every specific. ²

Footnotes:

3888. Those two kingdoms manifest themselves in man through the two kingdoms which exist within him - the kingdom of the will and the kingdom of the understanding which constitute man's mind, indeed man himself. It is the will to which the beating of the heart corresponds, and the understanding to which the breathing of the lungs corresponds. Those two kingdoms also manifest themselves in man's body, where again there are two kingdoms - that of the heart and that of the lungs. Anyone who knows this arcanum is also able to know about the influx of the will into the understanding and of the understanding into the will and consequently to know about the influx of the good of love into the truth of faith, and vice versa, and so about the regeneration of man. But people who are restricted solely to bodily ideas, that is, people who have evil as the object of their will and falsity the object of their understanding cannot grasp these matters, for they cannot think about spiritual and celestial things except with the senses and the body. Consequently they cannot think of those things except from a thick darkness concerning the things that constitute heavenly light, which is the truth of faith, and from a coldness concerning the things that constitute heavenly flame, which is the good of love. Those two - the thick darkness and the coldness - so blot out celestial and spiritual things that they do not seem to those people to be anything.