365. (2) The life of man in its first principles is in the brains, and in its derivatives in the body. In first principles means in its firsts, and in derivatives means in what is brought forth and formed from its firsts. By life in first principles is meant will and understanding. These two are what are in their first principles in the brains, and in their derivatives in the body. It is evident that the first principles or firsts of life are in the brains:
(1) From the feeling itself; since man perceives, when he exerts his mind and thinks, that he thinks in the brain. He draws in as it were the sight of the eye, contracts the forehead, and perceives the mental process to be within, especially inside the forehead and somewhat above it.
(2) From man's formation in the womb; in that the brain or head is first developed, and continues for some time larger than the body.
(3) In that the head is above and the body below; and it is according to order for the higher to act upon the lower, and not the reverse.
(4) In that, when the brain is injured in the womb or by a wound or by disease, or by excessive application, thought is weakened and sometimes the mind becomes deranged.
(5) In that all the external senses of the body sight, hearing, smell, and taste, with touch (the universal sense) as also speech, are in the front part of the head, which is called the face, and communicate immediately through fibers with the brains, and derive therefrom their sensitive and active life.
(6) It is from this that affections, which are of love, appear imaged forth in the face, and that thoughts, which are of wisdom, are revealed in a kind of sparkle of the eyes.
(7) Anatomy teaches that all fibers descend from the brains through the neck into the body, and that none ascend from the body through the neck into the brains. And where the fibers are in their first principles or firsts, there life is in its first principles or firsts. Will any one venture to deny that life has its origin where the fibers have their origin?
(8) Ask any one of common perception where his thought resides or where he thinks, and he will say, In the head. Then appeal to some one who has assigned the seat of the soul to some gland or to the heart or somewhere else, and ask him where affection and thought therefrom are in their firsts, whether they are not in the brain? and he will answer, No, or that he does not know. The cause of this ignorance may be seen above (n. 361).