THE NATURAL BASIS
SIGHT, THE VISUAL PROCESS, AND DOCTRINE
Aubrey T. AllenA501. It is stated that:
Faith, as to its existence in man, is spiritual sight. Now as spiritual sight which is sight of the understanding, and thus of the mind, and natural sight which is sight of the eye and thus of the body, mutually correspond, every state of faith may be compared with some state of the eye and its sight--a state of faith in what is true with every normal state of eyesight, and a state of faith in what is false with every perverted state of eyesight. (TCR 346)A502. According to this there are two kinds of sight, natural and spiritual. That there is a natural world of reality we can confirm by all of our bodily senses. However, it is not so easy to confirm the reality of the other, or the world of the spirit. In Arcana Coelestia 3721:2 it is said:
It appears to man that the objects of the world enter through his bodily or external senses, and affect the interiors; and thus that there is entrance from the ultimate of order into what is within; but that this is a mere appearance and fallacy is manifest from the general rule that posterior things cannot flow into prior; or what is the same, lower things into higher; or what is the same, exterior things into interior; or what is still the same, the things which are of the world and of nature into those which are of heaven and of spirit.Also, in Arcana Coelestia 3739:2.
In man that which is inmost inflows in like manner into that which is lower; and this in like manner into that which is lowest or last. The natural and corporeal consists of such an influx and concourse into those things which are beneath, and finally into those which are last.A503. Influx is from inmost to outmost, and to seek direct access to the spiritual world by means of sense experience is to invert the laws of order. We can, however, observe organic structure in the course of its development, and gain insight into what is normal and what is not normal; or that which is of order and that which is not of order. This, not only as to structure, but also as to function of structure.
A504. Now, if every state of faith may be compared to some state of the eye and its sight, we would think that in the course of our observation we could gain some insight into the doctrine of truth. The normal development of the eye and its function would correspond to true doctrine and enlightenment of the understanding, while abnormal development of the eye as to structure and function would correspond to false doctrine and obscurity of the understanding. As far as any individual is concerned, we know that this is merely representative and not necessarily correspondent. Nothing is reflected upon the person, but upon the thing that is represented (AC 665, 2010, 4281).
A505. It will be the purpose of this paper to investigate sight as a process, and to consider how the various states of sight of the external degree relate to, and correspond to, the various states of sight of the interior degree, both as to their normal and abnormal aspects, and to relate this to the Word and doctrine.
A506. The brain and the eye-visual pathway represent 2% of our body weight, but demand 25% of fuel input (nutrition). The eyes' visual pathway requires more fuel than any of our body's organ systems. It uses 1/3 as much oxygen as the heart, though it would take 60 eyeballs to equal the weight of one heart. Forty percent of all nerve fiber going to the brain originates in the retina, though it is one millionth of our body weight. Each eye can send a million impulses per millisecond to the brain. For the whole organism, including the eyes, there are as many as three million signals per millisecond.
A507. However, we must understand that when we use the term vision we must include more than just eyes and eyesight per se. Reliable sources indicate that at least 80% of learning occurs through the visual pathway, so we must consider vision as a process that includes the retina as a sense receptor, the brain as a control center, and the muscles of the eyes and body as external mechanisms to express behavioral responses triggered by sensory stimulation. This increases our scope to include vision and vision problems as part of the complete person as he performs in his every day environment.  And, as Gesell says:
the organ of sight is more than a dioptric lens and retinal film. It embraces an enormous area of the cerebrum; it is deeply involved in the autonomic nervous system; it is identified reflexively and directly with the musculature from head to foot. Vision is so pervasively bound up with past and present performances of the organism that it must be interpreted in terms of a total, unitary, integrated action system. A508. This leads us to understand more clearly why the Writings say that the eyes correspond to understanding. If we look at Arcana Coelestia 4410, it is said relative to correspondences:
It has been made clear to me by much experience that the sight of the left eye corresponds to truths which are of the understanding, and the right eye to affections of truth which also are of the understanding. Hence the left eye corresponds to truths of faith, and the right eye to the good things of faith.A509. This would lend itself to the thought that the left eye corresponds to what we clearly perceive to be true, and the right eye to what we clearly perceive to be good. Projecting this thought outward to things of creation, we can see so many things that are created with a dual nature, especially in the higher degree. Some reflect more of Divine Love, and others more of Divine Truth. From lowest forms to highest forms we have, successively by degrees, a revelation of the Divine Love and Wisdom until it culminates in the highest degree and the image of that love and wisdom revealed in the male and female form. Can we ever comprehend this reality? Man is, in the highest degree possible to express, the object of Divine Love and Wisdom. It is the object of this love to love others outside of itself, to desire to be one with them, and to make them happy from itself. It would appear, therefore, that the most important thing in life, and I cannot overemphasize this, would be to understand how we can better cooperate with this love, so that we may better be able to reciprocate with it. To do so we must understand more about it. It is said in John 1:1-4:
In the beginning was the Word, and the Word was God. The same was in the beginning with God. All things were made by Him; and without Him was not anything made that was made. In Him was life; and this life was the light of men.A510. Here it is said that there is life in the Word, and that it created all things. This would lead us to wonder what in reality life is. If we go to Divine Love and Wisdom No. 35, it is said:
there is such a union of love and wisdom and wisdom and love in God-Man…and since there is such a union of these, the Divine Life also is one. Divine Love and Divine Wisdom are one because the union is reciprocal, and reciprocal union causes oneness.A511. Thus, we should remember, life is one because it is the result of the reciprocal union of Divine Love and Wisdom, and this in God-Man. In John 6:63, it is said "the words that I speak unto you, they are spirit and they are life." Therefore, that which goes forth from the Lord as a result of the reciprocal union of love and wisdom constitutes life, and it is spiritual. It is spiritual as to essence, but in its ultimate form it is natural. This is the reason why, to the people of the Most Ancient Church, the world of nature was the Word. Their interiors were in a state of order, and for this reason to them the natural forms of creation were living correspondences revealing there a union of love and wisdom. This union of love and wisdom has to be in all created forms for it to have continual existence (DLW 36).
A512. If we want to understand more about the truth concerning life, we have to consult the Word, because the Lord is Speech and the Word (AC 1642). We learn from this source that the origin of life became flesh and dwelt among us (John 1:14). He therefore, has arms, legs, hands, feet, and eyes, just as you and I have. In man as to details of structure they are numberless; however, in God-Man, they are infinite (DLW 18). We should remember that the Word, as to its letter, has a natural sense that corresponds to the natural heaven; but internally it has a spiritual and celestial sense corresponding to the spiritual and celestial heavens (SS 6). It was written in this way so that all states of life, both in the natural as well as the spiritual world, could receive life from it.
A513. If we are to receive life from the Word, it is very important that we understand rightly how to approach it. We cannot approach it just any way, but it must be approached from a good affection, and for the sake of understanding truth for its own sake. Very few at this day do this, for most who read the Word do not read it from affection of truth, but from the affection of confirming therefrom the doctrinal things of the Church in which they were born (AC 6047). If we are to understand true doctrine we must approach it for the sake of truth itself, and this for the sake of life (AC 7053).
A514. Because the eyes represent understanding, and through these organs and their visual pathway 80% of our learning occurs, and because one represents love, and the other truth or wisdom, we can say that their reciprocal union represents life, or the Word. So, in our approach to the Word, let us here relate it to the eyes, and to the process whereby we acquire understanding of the Word. To do so we will first relate the globe of the eye to the Word in its three degrees, and thence to the three heavens.
1. The outermost coat, 5/6ths of which is made up of a posterior part which is white and opaque and called the sclera, and the remainder of which is an anterior transparent part called the cornea. (Represents the letter of the Word, or the natural heaven.)A516. We are, therefore, in a position to relate what has been said to the Word; to relate the globe of the eye in its three degrees to the Word in
its three degrees and to the correspondent heavens; and to view vision as a dynamic process whereby we acquire understanding of the Word.
A517. When light enters the eye it must enter through the pupil. The clear front surface of the eye, anterior to the pupil, is called the cornea and consists of a small portion of the outmost tunic. The outmost tunic of the eye represents the letter of the Word, or the natural heaven, and the small anterior transparent part of this tunic called the cornea would seem to represent those clear truths in the letter of the Word upon which our understanding must focus--such truths as "he that hath seen Me hath seen the Father" (John 14:9); also "for as the Father has life in Himself so hath He given the Son to have life in Himself" (John 5:26). The as-of-self effort to locate and find these truths from good affections, and for the sake of life, would seem to be represented by the extrinsic muscles. Once the as-of-self effort has located and found these truths they are positioned directly in front of the pupil. They then pass through the pupil and enter the crystalline lens capsule.
A518. The capsule encloses the lens of the eye through which light must travel. The accommodative power of the lens would seem to represent an intense desire to acquire understanding for the sake of life. This is part of the second tunic of the eye representing the interior sense of the Word, or the spiritual heaven. The desire to understand bends light toward the retina, and it is brought to a focus on the macula.
A519. The retina is the third or inmost tunic of the eye and represents the inmost sense of the Word, or the celestial heaven. The macula is the most sensitive area of the retina. When light strikes this area, behold, a strange thing happens. Natural light is converted into spiritual light, and man views the letter of the Word not from himself, but from the Lord. This area of the retina represents the Writings, and in particular the fovea, its inmost part, would seem to represent the Doctrine of the Lord. When light is brought to focus in this area, there is clear confirmation of those truths that have gained admittance through the pupil, especially those concerning the Lord. The scleral part of the outmost tunic of the eyes would seem to represent the clouds of heaven; but the clouds become transparent when the as-of-self effort locates them, and they then gain admittance through the pupil because they are seen in the light of the Heavenly Doctrines, from the Lord. We then see the New Jerusalem, the Holy City, descending from God out of heaven, and it is marvelous in our eyes.
A520. It would be good at this time if we reviewed some of the basic anatomy and physiology of the eye. If we are to relate the eyes to the visual process, we have to go beyond the retina tracing the visual pathway to the occipital cortex of the cerebrum--for this is the pathway, as represented in the Word, whereby the Lord reforms and regenerates man; and if we are to understand this process as it relates to our as-of-self part in it, a review of the anatomy and physiology of it will help, and then we can relate it to the Word.
A521. Once light enters through the various media of the eye and impinges on the retina it is converted in the retina into neural energy. Light does not, and this is a very important point, enter into the organ of sight. We cannot think in terms of putting such and such a stimulus into or through the organism. These nerve impulses arise within the organism as a result of firing by the organism's own cells. This energy is transmitted by the retina via the optic nerve to the optic chiasma. It is here that the nasal fibers of each retina cross over, or decussate, to join the temporal fibers on the other side of the opposite eye. Once they leave the chiasma, they constitute the optic tracts, and proceed backward and outward to pass around the peduncles of the cerebral hemispheres. As they wind around these each tract splits and forms two roots, a larger lateral external root, and a smaller medial internal root. Fibers of the larger root proceed to the external geniculate body, while the fibers of the smaller root proceed to the ciliary body. Therefore, on the left side, the fibers of the left external geniculate body receive fibers from the temporal fibers of the left retina, and nasal fibers of right retina; and the right external geniculate body receives fibers of the right temporal retina and nasal left retina. They proceed from thence in the form of optic radiations. They end up in area 17, known as the visuo-sensory area. In the calcarine cortex we have a visual center of a higher order. To establish single vision, the nerve impulses from both retinas must be unified. The right and left are united in such a way that we are entirely unconscious of any separation they have undergone. Other modifications of the impulses from the eyes take place here, and unified modified impulses are sent higher up into the nervous system.
It is interesting that in animals stimulation of the striate area results in ocular deviations; in man, however, this does not occur, but only on stimulation of the peristriate ocular motor area, a finding indicating that in him these reflex functions have been completely transferred to a region of higher association.A523. In regard to this transfer region Adler says:
Outside area 17, and closely following its contours, are two other areas which are concerned with visual reactions also. These have been termed the paristriate area or area 18 and the peristriate area or area 19…Area 18 has been considered the visuomotor field and area 19 the visuopsychic field…The anatomic boundaries of these areas are not exact, and not only their function, but also their location and extent have been disputed. This is due partly to differences in various species. In man, for example, area 18 plus area 19 is almost three times as large as area 17. In the orangutan, area 18 plus 19 is not even twice the size of area 17, and, in the monkey, area 18 plus area 19 is still somewhat smaller in relation to area 17.A524. The macula fibers form a separate group from the rest of the retina. They run directly from the fovea to the disc in a compact bundle…The macula fibers…lie on both sides of the perpendicular line through the fovea [and] are both crossed and uncrossed…[in their progression]. In lower mammals, large numbers of retinal fibers run to the superior colliculus and…provide an integrating mechanism of considerable complexity in relation to visual impulses. [This is not true in man, so far as is known; all these fibers end in the lateral geniculate body.] In man, the lateral geniculate body is the exclusive source of fibers in the optic radiation…[and] give rise to new fibers, forming the third neuron in the optic pathway. This proceeds through the optic radiation to the cells in the striate area of the calcarine cortex. In man, all the visual fibers end in the so-called striate area of the cortex…In monkeys, much of area 17 [the striate area] is found on the lateral surface of the occipital lobes.
A525. The message which is relayed to the visual sensory cortical area [area 17] enables one only to see. It does not enable a person to recognize what he sees nor to recall things which have been seen. [In order to do this the message must be sent to the peristriate areas 18 and 19, and to the angular gyrus where information for visual symbols is found.]
A526. If the sensory system alone were involved, and it was not necessary to trace this stimulus any further than its representation in the cuneus, we would have no problem so long as the sensory receptor and the conducting sensory nerves were intact. However, the final and most important element of seeing is the effector system.Goldstein says, "the efficacy of the outside stimulus is determined by the effector itself…in other words the effect is really caused by the effector." This is also stated by Renshaw when he says that seeing is motor. We will discuss this in greater detail later when we consider the perceptual act.
A527. In the seeing mechanism there are two types of effectors, visceral or autonomic, and skeletal or somatic. The visceral operates through smooth muscle, while the skeletal operates through striated or striped muscle. The visceral operates the muscles controlling the crystalline lens, the iris, etc., while the skeletal operates the extrinsic muscles that serve to move the eyes in their orbit. According to what has been said, if the effectors really cause the effect, and if reception is really determined by the condition of the effectors, then seeing is dependent upon the reciprocal relationship between these effectors. If, in the act of seeing, this dual effector system must work together as one in order to accomplish its use, which is vision, it would seem to represent a functional concept of conjugial love, relative to the visual process.
A528. Therefore, to recapitulate, the visual process involves three degrees, just as the globe of the eye involves its three degrees; both corresponding to the Word and the heavens in their degrees. The three degrees of the visual process are as follows:
A529. In future papers we will trace the visual process from the retina to area 17--and relate it to the process whereby the Lord reforms and regenerates man. It seems to recapitulate the history of the human race; also the history of the churches on earth and in each individual; also the pathway that the Lord took in the glorification.