When the body is no longer able to perform its functions in the
natural world, a man is said to die. Still the man does not die; he is
only separated from the bodily part which was of use to him in the
world. The man himself lives. He lives, because he is man by virtue,
not of the body, but of the spirit; for it is the spirit in man which
thinks; and thought together with affection makes the man. It is
plain, then, that when a man dies, he only passes from one world into
the other.... The spirit of man after separation remains awhile in the
body, but not after the motion of the heart has entirely ceased. This
takes place with a variation according to the diseased condition of
which the man dies. As soon as the motion ceases, the man is
resuscitated. This is done by the Lord alone.
--_Heaven and Hell, nn._ 445, 447