91. From the human face it can be seen what correspondence is. In a face that has not been taught to dissemble, all the affections of the mind present themselves to view in a natural form, as in their type. This is why the face is called the index of the mind; that is, it is man's spiritual world presented in his natural world. So, too, what pertains to the understanding is presented in speech, and what pertains to the will is presented in the movements of the body. So whatever effects are produced in the body, whether in the face, in speech, or in bodily movements, are called correspondences.