4042. Hence then it is that through man alone is there a descent from the heavens into the world, and an ascent from the world into the heavens. It is the brain and its interiors through which the descent and ascent is effected; for there are the very beginnings, or the first and the last ends, from which each and all of the things of the body flow forth and are derived. There also is the source of the thoughts of the understanding, and of the affections of the will.