There is a correspondence of the will and understanding with the
heart and lungs, consequently a correspondence of all things of the
mind with all things of the body.

(3) The will corresponds to the heart.

(4) The understanding corresponds to the lungs.

(5) By means of this correspondence many arcana relating to the will and
understanding, thus also to love and wisdom, may be disclosed.

(6) Man's mind is his spirit, and the spirit is the man, while the body
is the external by means of which the mind or spirit feels and acts in
its world.

(7) The conjunction of man's spirit with his body is by means of the
correspondence of his will and understanding with his heart and lungs,
and their separation is from non-correspondence.

372. (1) All things of the mind have relation to the will and
understanding, and all things of the body to the heart and lungs. By the
mind nothing else is meant than the will and understanding, which in
their complex are all things that affect man and all that he thinks, thus
all things of man's affection and thought. The things that affect man
are of his will, and the things that he thinks are of his understanding.
That all things of man's thought are of his understanding is known, since
he thinks from the understanding; but it is not so well known that all
things of man's affection are of his will, this is not so well known
because when man is thinking he pays no attention to the affection, but
only to what he is thinking; just as when he hears a person speaking, he
pays no attention to the tone of the voice but only to the language. Yet
affection is related to thought as the tone of the voice is to the
language; consequently the affection of the one speaking is known by the
tone, and his thought by the language. Affection is of the will, because
all affection is of love, and the will is the receptacle of love, as was
shown above. He that is not aware that affection is of the will confounds
affection with understanding, for he declares it to be one with thought,
yet they are not one but act as one. That they are confounded is evident
from the common expression, I think I will do this, meaning, I will to do
it. But that they are two is also evident from a common expression, I wish
to think about this matter; and when one thinks about it, the affection of
the will is present in the thought of the understanding, like the tone in
speech, as was said before. That all parts of the body have re