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
1. The heart corresponds to our volition and therefore to affection of love as well, while the breathing of the lungs corresponds to our intellect and therefore to thought: 3888. In the Word, then, the heart means volition and love: 7542, 9050, 10336; and the soul means intellect, faith, and truth, so that "from the soul and from the heart" means what comes from intellect, faith, and truth, and what comes from intent, love, and good: 2930, 9050. On the correspondence of the heart and lungs [Latin anima, "soul," also means "breath"] with the universal human or heaven: 3883-3896.
2. The heartbeat and the breathing of the lungs are regulative throughout the body and flow in together everywhere: 3887, 3889-3890.