387. The mind of man is his spirit and the spirit is the man because by mind are understood all the things of man's will and understanding, and these exist in first principles in the brains, and in their derivatives in the body; thus they are all things of man as to their forms. Since that is so, the mind, that is, the will and understanding, impels the body and all parts at will. Does not the body do whatever the mind thinks and wills? Does not the mind encourage the ear to hear and direct the eye to see, the tongue and lips to speak, impel the hands and fingers to do whatever it pleases, and the feet to walk whither it wills? Is the body anything but an obedience to its mind; and can the body be such an obedience unless it has the mind in its derivatives within it? Is it consistent with reason to think that the body obeys because the mind wills it so to do? If that were so they would be two, the one above and the other below, and the one will issue orders which the other will attentively obey. Because this is not at all compatible with reason, it follows that man's life is in first principles in the brains, and in its derivatives in the body, as has been said above (n. 365); also, that such as life is in first principles, such it is in the whole and in its every part (n. 366); and that from these first principles life is in the whole from every part, and in every part from the whole (n. 367). That all things of the mind have relation to the will and understanding, and that these are receptacles of love and wisdom from the Lord, and that these two make the life of man, has been shown in the preceding pages.