113.  The conjunctions between the will and the understanding, which are almost too wonderful to comprehend, can be illustrated by the way the heart and lungs act together.

114. Perhaps there are people to whom this subject seems simple and straight forward. Others may experience difficulty. But for all, a reading or re-reading of Part V of DLW is highly recommended. The wisdom therein is often transcendent, and there are numerous cherubim (see AC 308). However, the prepared mind can enjoy many fascinating walks in paradise, and even see birds of paradise (DLW 374). In what follows we descend somewhat to natural and scientific things, for we are so constituted that it is necessary for us to keep our feet on the ground (AC 4939; 2557:2). This we do with the aid of correspondences (AC 9300:3), and we hope to progress by walking (AC 519). Our need to think from correspondences is also spelled out in DLW 402, where we read:

Why it is so cannot be fully described except in spiritual language because love and wisdom, and will and understanding therefrom, are spiritual concepts, which can indeed be taught in natural language, but only so as to be vaguely perceived on account of the ignorance of what love, wisdom, affections of goodness, and affections of wisdom which are affections of truth, are. Yet one can see the nature of the betrothal and of the marriage of love with wisdom, or of the will with understanding, through the parallelism that exists in their correspondence with the heart and lungs. For it is the same with these as with love and wisdom, so much so as to make absolutely no difference except that one is spiritual and the other natural.
This statement (like several others) encourages us to attempt to see the spiritual in the natural, and we hope that our modern knowledge of the natural will enable us to picture the spiritual more clearly. But for our knowledge of the spiritual itself we are still dependent on the natural language in the Writings and it is inevitable that we shall be labouring with spiritual concepts "vaguely perceived."

The conjunction of the heart with the lungs by arteries and veins portrays the way the will acts into the understanding causing affection, perception and thought

115. We have contemplated the activities of the heart and lungs in the body as a whole and we have seen how these activities are integrated so closely that they form one service to the body and reflect the far-reaching influence of love united with wisdom in the whole mind (Nos. 77, 78, 106-111). It is obvious, however, that this unity in service could not exist without that other union within the chest through arteries and veins. A general idea of how the heart is joined to the lungs through arteries and veins can be obtained from Figure 2. This is to give a first, most general picture of the whole heart-lung system. A more detailed anatomical drawing of the opened heart has been presented in Figure 3. Figure 4 shows a more accurate but still modified drawing of the arterial connections to the left lung. The conjunction of the heart and lungs through their blood vessels enables them to be together in their effect, which is the maintenance of conditions necessary for the life of all the tissues in the whole body. Similarly, the will and understanding provide conditions for the life of the whole mind, and nothing is more important than their life together which develops through three conjunctions (DLW 404). These conjunctions take place "after the nuptials," but as the nuptials mean man's state from ignorance to intelligence and thence to wisdom, they would seem to cover the whole of man's mental progress. The conjunction of the will and the understanding is compared to a marriage, and the definition of nuptials suggests that the conjunctions should always be preceded by something of a marriage. Also that a binding covenant is not merely entered into once and for all, but that all conjunction should begin with a wooing, and progress through consent to a holy agreement. Such a sort of wooing may even be considered relevant on the merely physiological level of the operation of the lungs; for in disorderly states there can be so much tension and constriction of arteries and chest muscles that breathing cannot function properly. In states of good order the "request" by the control centres (see No. 124) for more air is quickly met by increased ventilation in the lungs.

Click figure to enlarge
Pulmonary and Bronchial Arteries 

              Schema to illustrate the difference between the pulmonary and bronchial arteries (left side only). The trachea and lung have been displaced far to the right of the diagram, and the arteries have been correspondingly lengthened. There are usually two left bronchial arteries (as shown) but only one to the right lung. It arises from
 the third intercostal artery which is, itself, a branch from the aorta. 

              Source: Clemente, Gray's Anatomy, 30th American ed., figs. 7-25, 8-53, 15-24, text pp. 729, 1398. Based on sketch by N. J. Berridge.


The will and the understanding are joined by three affections corresponding to blood vessels and three offspring are produced corresponding to structures in the lungs

116. The three conjunctions of the will with the understanding arise through three affections: (1) for knowing, (2) for understanding, (3) for seeing truth. Each conjunction produces its particular offspring: (1) affection for truth, (2) perception of truth, (3) thought. We now consider each conjunction in more detail, as diagrammed in figure 5, and find that the first conjunction takes place through an affection for knowing, as already said, but this leads to an affection for reasoning and forming conclusions on matters the person delights in. When this latter affection is exalted to spiritual things it becomes the affection for truth. These various affections are from the will in the understanding and thus correspond to blood vessels in the lungs.

117. The second conjunction takes place through an affection for understanding which gives rise to the perception of truth. The affection and the perception are so related that we may conclude that one who loves to understand can perceive truth according to the extent of his love. Again the affection corresponds to blood vessels, but perception and the thoughts from it correspond to the branches of the air ducts or bronchia (DLW 405).[5]

 Click figure to enlarge

The three conjunctions of Divine Love & Wisdom 404-420 

It can be seen by the flow of the blood out of the heart into the lungs the will flows into the understanding and produces these results. (DLW  405) 
Drawn by Tony Rose with Rev. Thomas Rose.


118. The third conjunction takes place through an affection for seeing truth, from which springs thought. Once more, affection corresponds to blood vessels, but thought in this context seems to correspond to the air saccules. We find in DLW 413:

The minutest air cells, which are receptacles for the air used in breathing; these are the things with which the thoughts act in conjunction by correspondence.

The minutest air cells are a sort of continuation of the branches of the bronchia, for these continue to divide until they reach the microscopic size of the air cells. Thus the perception from the second conjunction is related to the thoughts from the third.

There are three conjunctions between the will and the understanding but only two sets of arteries between the heart and lungs

119. While this section of DLW repeatedly invites us to study the anatomy of the lungs and heart and their conjunction, the exact correspondence between the mental or spiritual things and the bodily things is not always clear, and it is difficult to relate DLW 405 precisely to No. 404. It is said in 405:

It may be seen from the influx of the blood from the heart into the lungs, how the will inflows into the understanding and brings to pass those effects…relating to the affection and perception of truth and relating to thought.
 Still, the bodily correspondence of the three conjunctions eludes us. For we have three affections: (1) for knowing, (2) for understanding, (3) for seeing truth; but in DLW we have only two routes of corresponding arteries: (1) the bronchial, (2) the pulmonary (and the veins we need not consider, as they merely provide for the return flow).

120. When we consider the pulmonary arteries we find with surprise that there is no comment in DLW on the fact that the pulmonary arteries take the whole stream of blood (for it comes together into the right side of the heart and is then all discharged through the lungs). Perhaps this is meant when it is said that the pulmonary arteries come from the heart alone (This point is further discussed in No. 172). The way the blood flows can be imagined from Figure 2. The actual anatomic arrangement within and around the heart is shown in Figure 3. No organ other than the lungs takes the whole of the blood supply in this fashion. Although so little is said about this peculiarity of the pulmonary circulation, the correspondence of it is described where it is said that the love does nothing except in conjunction with wisdom (DLW 409). Thus pulmonary and bronchial arteries differ from one another more than one might imagine from a reading of the text; indeed they could not be more different: The pulmonary arteries take all the output from the right ventricle and direct it to the air-saccules of the lungs, while the bronchial arteries take a little of the output from the left ventricle and direct it to the bronchial tubes and associated structures as well as to the surface of the lungs beneath the pleura, but not to the air saccules (alveoli). Figure 4 assists visualization. The bronchial arteries are for the nutrition of the lungs; the pulmonary arteries are for making use of the lungs to refresh the whole of the blood before it is re-distributed to the body. So we have two very different circulations; but we need a third if we are to have a special circulation to correspond with each conjunction. In DLW we are not told that either of the two sets of arteries corresponds to a particular conjunction. This reticence probably arises from the need for accommodation to the limited knowledge of the period (see, e.g., DLW 405, 512). A brief survey of modern knowledge shows the subject to be
sufficiently complex and makes clear the need for reticence at that time. However, complexity need not induce us to fear making a search for a third circulation which we would hope to be so different from the other two that it could easily be recognized as a third, and not merely as a subdivision of either of the others. It may nevertheless be possible that one or other of the two systems we already have could be clearly divided to make three in all. This possibility must not be ignored and, therefore, we must look more closely at the anatomy of the pulmonary and bronchial arteries.

121. The branches of the bronchial artery become more numerous and finer as they ramify along the bronchia and bronchioles among other structures. The finest branches are, of course, the capillaries through which nourishment passes to the various tissues other than the air saccules. The bronchial system does not reach to these. However, there is a very abundant blood supply to the air saccules through the pulmonary system which must therefore supply nourishment to them. Although the blood in the pulmonary artery is depleted in oxygen, it is not likely to be so depleted in other nutrients (amino acids, glucose, vitamins, minerals) that the abundant flow will not compensate for the lower level of those nutrients.

122. Soon after leaving the heart, the pulmonary arteries form several branches which differ merely in supplying different segments of the lungs, and it would be difficult to justify a division into two systems rather than several, especially as this would merely be a minor subdivision.

122A. The bronchial arteries can be divided into three groups and the veins into two. The three groups of arteries supply the walls of the bronchia, the areolar tissue between the lobes of the lungs, and the surface of the lungs beneath the pleura. The veins fall into two systems, one of which empties into pulmonary veins or the left (!) atrium, the other into one of the azygous veins or an intercostal vein, but also communicating with the pulmonary veins. Thus, some of the blood flowing into the bronchial arteries finds its way into the pulmonary veins rather than the bronchial veins and thus returns to the same side of the heart that it left. Branches of the bronchial arteries also join those of the pulmonary arteries in parts of the pleura and smaller bronchi.
    But these are clearly not the two ways in and the two ways out referred to in DLW 405, and the complexity of the whole system prevents our dividing it into two groups with any degree of confidence. Thus we are still left with only two circulations and our search for a third must take us farther afield.

A proposition concerning the three correspondences requires further study

122B. A proposition is developed below with the intention of including other organs that assist the heart and lungs to act jointly. These organs must have their correspondences or they would not exist. Their importance is easily discerned when they are described, but it shows up still more clearly when we think about the development of the embryo, because they help to explain the difference between "the heart first forms the lungs" and "afterwards conjoins itself with them" (DLW 402). The explanation hinges on the fact that the organs to be described are not active in the embryo but, like the lungs themselves, become active after its birth. For one may ask how the heart can first form the lungs without being in some way united with them. Can it do so at a distance? If it does not, one might suggest that the bypassing of the blood flow through the foramen ovale and ductus arteriosus shows a withholding of the full stream of blood from the heart into the lungs so that the heart could be imagined as drawing back from full conjunction. But then it would be as already suggested, that conjunction could not be represented by the
mere presence of arteries in the lungs and scarcely by the mere flow of blood through them on its way to the capillary beds. Nor could we define adequate representations of three conjunctions by the types of arteries present.

122C. We are encouraged by DLW to include the embryo in our studies, for this section of DLW (no. 398) includes 22 propositions. No sooner do we come to the exposition of the second one (DLW 400) than we are invited to consider the embryo as follows:

It is a known fact that all things of the body are formed in the womb…through fibres from the brains and…blood vessels out of the heart.
In no. 402 near the end we find:
The heart first forms the lungs; and afterwards conjoins itself with them; it forms the lungs in the embryo, and conjoins itself with them after
There are now many more "known facts" which enable us to add detail to the statement that the heart first forms the lungs and to see by how much or how little the heart first forms the lungs and to see by how much or how little the heart conjoins itself with them during this formation. So we launch into a small bay of the sea of Embryology.

There is close association between heart and lungs before birth

122D. The very young and very small embryo develops quickly. Rapid changes take place during the first few weeks but the fourth seems particularly dramatic. Early in the fourth week, the embryo being only 2.4 mm long, the umbilical arteries and veins are already defined and are beginning to link up with vessels which will complete the chorionic circulation. By comparison with the chick embryo, it is thought that the heart begins to beat at about this time. As the channels for circulation are not yet complete, the fluid in them can only flow to and fro. At this same time, the lungs begin to grow as buds on each side of the oesophagus. They are nourished at this time through a network or plexus of capillaries connected with the aortic sac (which is a relatively wide, odd-shaped vessel between the ventricle and the beginnings of the aorta). There is a well marked dorsal aorta at this time and to this the capillary network (plexus) is eventually connected, and it then grows into a distinct artery, all the time remaining as the route for the supply to the lung buds. The new artery is known at this stage as the 6th aortic arch, but it shortly
becomes recognizable as the pulmonary trunk. Connection between the heart and lungs thus begins at a very early stage, as indicated in DLW, though in those days anatomists probably could not see details in the embryo which is only 2.4 mm long. An advanced technique of fixing, staining and serial sectioning is probably needed in addition to a good microscope and observations of living specimens.

122E. Three phases are recognized in the development of the lungs. During the first one, which is known as the glandular phase, the lungs are mostly a concentrated mass of tissue with an appearance normally associated with glands. This period lasts from the beginning of embryo development to the 11th week. Thus it includes the development described just above when the pulmonary trunk is being formed. The second phase is the canalicular. It lasts from the 16th to the 24th week, and during this time the channels proliferate and branch and some cells become flattened and applied close to capillaries. The third stage is the alveolar. It covers the major development of the alveoli. It lasts from the 24th week until after the birth. Although the foramen ovale and the ductus arteriosus cause most of the heart's output to go into the aorta, the pulmonary arteries are not blocked. There must be some flow through them which may well be enough to provide for the growth of the alveoli and their surrounding capillaries, for these tissues are so delicate that their total mass is small. There is some belief also that in the newborn, the
anastomoses, or junctions between the bronchial and pulmonary systems, are more extensive than they are later.

122F. During their development, the alveoli have no air to open them and allow room for proper growth, but they are expanded by fluid from other tissues. Some embryologists believe also that respiratory movements before birth cause some of the amniotic fluid to be drawn into the lungs. Even before full term, i.e. after premature delivery, the lungs are capable of respiration once the efforts, or assisted efforts, of the fetus have ejected the fluid so that air can be drawn in from the surrounding atmosphere. After birth the alveoli continue to develop. They become more numerous and complex in shape as they keep up with the increase of bodily size.

122G. The bronchial arteries arise from the descending aorta (Figure 4) or from the posterior (aortic) intercostal arteries. As previously noted, they supply the various air passages in addition to other tissues. Once circulation is established, new arteries grow out as branches from earlier ones and it is clear that the bronchial arteries will be functioning in the canalicular phase if not sooner. They will be taking their full quota of blood. A limited quantity will also be flowing through the pulmonary arteries and it may seem that conjunction between the heart and lungs is progressing. As for the closeness of conjunction, it seems that from about the fourth week after fertilization of the ovum, if not earlier, conjunction has been very close indeed. It has extended to the intimate relationship necessary for the transfer of so many nutrients and growth factors from the blood to the growing cells. This adumbration of a few facts from the great array in embryology gives us some appreciation of "the heart first forms the lungs."

After birth conjunction is for the sake of use

122H. In view of the close union between heart and lungs for so long before birth, how can we explain an even closer union which conjunction appears to mean? The blood has already been flowing through all the vessels for a long time, though at a slow rate through the pulmonary artery. We need to note that Swedenborg wrote of conjunction after the birth although he obviously knew that the formation of the lungs involved a close association with the heart. Why then did the situation after birth promote conjunctions? The philosophy of the Writings can come to our aid. It need not be brought forward in detail but it seems to show that the normal progression of end to cause to effect occurs only for the sake of use.

122I. If this philosophy be applied to the heart-lung situation, we see that the end or purpose of all development is use in the body, in order that the body may be useful so the neighbor and the Lord may be served. It might be accepted, therefore, that it is use that unites. The heart and lungs cannot be fully united until they are in use. This happens only after birth. Therefore, we then have conjunction, and indeed it is easy to see three conjunctions once it is accepted that use is essential.
    It is difficult to decide which order to suggest for the three conjunctions. The first might mean the most important, or the first in time. DLW 404 seems to refer to first in time since it corresponds to the early development of the intellect. We cannot, however, choose a first in time for the correspondences unless we go back to the embryo when conjunction had not taken place. We can choose a first after birth if we are allowed to distinguish different periods separated only by seconds. The bronchial artery has been in full use all the time and after birth it continues to function before the child's first breath, using the residual oxygen supplied a few seconds earlier from the mother's lungs, via the placenta. It therefore seems reasonable to place the bronchial artery as corresponding to the affection which produces the first conjunction. Before the first breath the fluid in the lungs must be expelled to make room for the air. This requires the muscles of the chest and probably other muscles of the
trunk. These also belong, as it were, to the heart and lungs for they grow and they work only by means of blood sent to them by the heart through the aorta and their work enables the lungs to breathe. They must therefore correspond to the second conjunction or to part of it. It is not, however, until the third conjunction takes place that the other two are valid. Without it they are useless, not actually conjunctions. They fade away. The child dies. But if the pulmonary artery opens and plays its part, the third conjunction is secure. The lungs are opened as to their minutest blood vessels which allow the blood in them to take up oxygen from this the baby's first breath. All the organs in the activities just mentioned, even the heart itself, continue to function after birth by means of the oxygen drawn in and then transferred through the pulmonary vein in blood supplied a few moments before through the pulmonary artery. The exhalation of carbon dioxide is equally important.
    Time has been split into small intervals to show an order of first, second and third for the conjunctions. It has also shown how three stands for what is full and complete, for if anything is missing, all the conjunctions come to naught. This concludes the presentation of this particular proposition, but parts of it need to be explained in more detail.

How the chest and its muscles facilitate the breathing of the lungs

122J.The chest and its muscles have only been mentioned in passing, but they must be integrated with the rest of our picture. An obstacle to the clearer understanding of correspondences is the belief that the two arterial systems supplying the lungs enables them to breathe at a different rate from the heart's beat. Let it be understood that what makes the lungs inflate is the contraction of certain muscles of the chest and diaphragm. The cage of ribs is so structured that when certain muscles between them contract, the volume of the chest is increased. The three dimensional geometry behind the movement is subtle but the facts are plain. Other muscles quite nearby can serve to diminish the volume and so expel air, but expulsion is often an effect of relaxation. The muscular diaphragm is effective because its domed shape is flattened when its muscles contract. This is a simplified account from conclusions from a great deal of experimental work published in the medical literature. Some of the evidence varies in detail, but for the picture as a whole, it is uncontroversial and more than adequate. We can therefore allow ourselves to believe that ribs, muscles and diaphragm enable the lungs to be expanded.

Two ways by which blood enables the lungs to be expanded

122K. The need for activity of the diaphragm and chest muscles (intercostals) corresponds well with the spiritual fact that the understanding does nothing of itself (DLW 412). It is added that all the conditions of the lungs depend upon the blood and "when the inflow of blood stops, breathing stops." This is because the lungs can do nothing of themselves. Now we can see more detail of how the blood flow enables them to breathe. As is said in DLW 413, "this cell-like substance [the alveoli] is such that it can be expanded and contracted in twofold fashion." The evidence now is that the bronchial arteries have little to do with the actual mechanics of the expansion, but the alveoli are indeed expanded in two ways as follows: (1) blood from the pulmonary artery causes the expansion of the network of capillaries around each alveolus; (2) blood from the aorta goes to the intercostal muscles (i.e. those between the ribs) and to the diaphragm, enabling them to expand the chest and hence the alveoli so as to draw air into them. (Some readers may like to be reminded that the aorta is the highway for blood travelling to the body from the heart. The intercostal muscles are not supplied through the bronchial artery but through a different one also, of course, branching from the aorta.) These matters of anatomy and physiology show Swedenborg having to write within the scientific limits of his time but being biased towards a correct view by the angelic wisdom. He was allowed to say expanded in two ways (DLW 413), but not to say what the two ways really are.

122L. Perhaps it can now be seen that a better appreciation of the will and the understanding and of their conjunction can be obtained with the help of modern anatomy and physiology if we also widen our field of view according to the hints we find in many places. First, in DLW 408 we read that love introduces wisdom "into many things of its house" and that the house means the whole man, also that "the lungs are introduced into all…[parts of the body] in the same way as the understanding into all things of the mind." Moreover, we have already noted that there is a union of the heart and lungs everywhere in the body (no. 108) though in the AC this is modified by "as it were."

Respiration is regulated according to the state of blood in the aorta

123. The collaboration between heart and lungs in supplying oxygenated blood to the whole organism (no. 115) shows how they work together for the sake of use. What is to be seen of this use in every organ is the last link of a segment of the end-cause-effect chain. There is, however, a link or two missing in the earlier part of this chain as we now view it, because we have not examined adequately the facts concerning the mechanism by which the lungs are expanded and contracted. The diaphragm and the muscles between the ribs have been mentioned as the means whereby the lungs are expanded,[6] but those muscles cannot, of themselves, respond to the varying requirements of the body for air. Therefore, there are special centres which monitor the condition of the blood and provide information enabling the control centres to maintain the activity of the chest muscles and diaphragm at the optimum level. One does not often realize the importance of these centres. It is scarcely
possible to imagine the breathing being fixed at a constant amount, for if it were sufficient for vigorous activities there would be drawbacks during quieter periods. It would impose unnecessary work loads on the chest muscles and dry out membranes lining the nose, throat and bronchi. It would also remove too much carbon dioxide (CO2) from the blood, thereby upsetting the very important acid-base relationship (most people have experienced giddiness after blowing too much). It would seem, then, that this control is a most important function to ensure the satisfactory working of the heart and lungs, and it is interesting to look at it a little more closely.

Diagram of Factors in Respiration Control

     Source: David K. Rubins, The Human Figure. 



124. What makes a child take its first breath (i.e., the mechanism through which the inflowing life from the Lord operates) is still a matter of speculation. Dejours (1981, p. 169) suggests several stimuli, but once breathing has started, control is necessary. There are structures, probably in the medulla oblongata, certainly in the carotid bodies (see below) and probably elsewhere, that are sensitive to the amount of oxygen (O2), carbon dioxide (CO2) and acidity (pH) in the blood. These sensitive structures send impulses to the respiratory centres also in the medulla oblongata. Signals are also received from muscles of the chest, from the lungs themselves, from moving parts of the body by reflex action, and probably from the brain itself. The respiratory centres then presumably process all this information and "instruct" the muscles which expand the chest to make appropriate movements. Figure 6 provides a pictorial summary of this chain of events. The carotid bodies mentioned just above are found in the neck at the junction of the internal and external carotid arteries. They are sensitive to oxygen and carbon dioxide in the blood which circulates through them and although they only control ten to fifteen percent of the breathing (via the respiratory centres), this may be enough to maintain a steady state under certain conditions. Control to the extent of one hundred percent is often in command, e.g., in sleep, and it is to be assumed that other monitoring devices contribute. Some, for example, are to be found near the arch of the aorta. All these sensory bodies are in a position that enables them to respond to the chemical composition of the blood soon after it leaves the heart. So they are part of the continuous monitoring system that determines how the chest and diaphragm will respond to the needs of the rest of the body by drawing air into the lungs more frequently or less, more deeply or less. From what has already been said it is clear that the muscles which change the volume of the chest are an essential part of this system that is being suggested as a correspondence of the second conjunction (no. 122J). As already stated, the respiratory centres in the medulla oblongata issue instructions, according to the information they receive, thus bringing into being a viable system for the control of breathing.[7]

125. As the medulla oblongata is part of the brain, the respiration depends on fibres from the brain. But we are told (DLW 412) that it is respiration of the spirit that depends on fibres from the brains. These fibres are probably of an origin different from that of the former ones. This would enable its main brain (or higher centres, i.e. the cerebrum and cerebellum) to overrule the lower parts of the brain, one of which is the medulla oblongata. Conscious control, which is of the will or spirit, can obviously overrule for a limited period. Unconscious effects such as lead to sighing are well known to result from a state of the spirit.

126. The necessary involvement of the central nervous system corresponds presumably to the impossibility of explaining the activity of man's understanding without involving influences from the spiritual world. It is inevitable that in our thoughts we link the involvement of the nervous system with the more internal activities of will and understanding, for the "messages" from the carotid bodies must go through higher centres before they can affect the lungs. So we immediately think of conscience, and conscience is a species of perception (AC 2144:3). Thus we have arrived at the second conjunction of DLW 404, "from which springs perception of truth." However, we must not forget that what the respiratory centres "perceive" is the state of the blood, not the freshness of inspired air, so their activities including those of the carotid bodies would correspond to a persons perception of his need rather than of Truth from the Lord. We also keep an open mind about the validity of this interpretation, as it is said that, "the branches of the bronchia of the lungs [correspond] to perceptions and thoughts…" (DLW 405). The
possibility of different perceptions corresponding to different structures is considered below (No. 139).

Three circulations may correspond to the three affections

127. We now have three clearly defined routes of circulation which are of special importance to the lungs:

1.     the bronchial arteries branching from the aorta (some directly, some indirectly),
2.     the aorta and those of its branches that are necessary for respiration, and
3.     the pulmonary arteries stemming directly from the heart.

It is suggested that these circulations correspond in this order to the three conjunctions of DLW 404. It is the picture as a whole that leads to the choice of this order and it will become clear in what follows, but some of the detailed argument is summarized in footnote 10 in No. 142.

128. In an earlier essay the second conjunction between the will and the understanding was said to correspond to that of the heart with the bronchia through the bronchial arteries (Berridge, 1979B). Perhaps this is true also. Since each part is an image of the whole (HH 58), each conjunction bears a resemblance to all three as they follow one another in due order to make one mind.

129. We may now compare the three arterial systems with the three conjunctions described in DLW 404.

The bronchial arteries correspond to affections by which the understanding is nourished

130. This is clear from what has already been said (120, 121, 122E, and 122G) about the nourishment of the lungs and associated tissues through the bronchial arteries, and about the correspondence of the lungs with the understanding. These arteries are said to be "almost separate from the heart" (DLW 413, 415). Nevertheless, as we have seen, "the heart first forms the lungs" and the arterial connections are very close, though, clearly, not so immediate as those of the pulmonary arteries.[8] This "almost separate" is such an important distinction and yet seems rather artificial, for the blood in the bronchial arteries was in the heart a few seconds earlier. However, it probably refers to the great difference between the bronchial route of circulation and the pulmonary route as already emphasized above (No. 120).

131. The bronchial arteries also nourish structures associated with the lungs, such as the pleura, for example. Thus we see how, in the early stages of the growth of the understanding, the affections producing the growth are slightly different from the main will or perhaps ruling love; various affections also nourish associated things necessary for the proper functioning of the understanding. So the bronchial arteries are complex both in functions purely their own and in their varying connections with the pulmonary arteries and veins. Is not this picture typical of the complexity of the growth of the mind? Obviously, and in agreement with the correspondences, the affections play a predominant part. However, we see in the bronchial system arteries which do not come directly from the heart but from the aorta, and as they branch, so they seem to be further away. This suggests that the understanding grows by many affections, some more nearly, others more distantly related to love. It is obvious that there are many ways by which the growth of understanding is stimulated, and knowledge is sometimes gathered even in
spite of the affections. It is not so very long since education by punishment was the vogue, and it was, to some extent, effective. The understanding is sharpened by pain, fear, and many other emotions somewhat distantly related to love. Even boredom will drive some of us to exercise our understanding as a means of escape. Pain and fear have no relation at all to love of the subjects of education, but they are related to the love of self. It may well be that the bronchial arteries, or parts of them, correspond even to affections derived from the love of self, for there is a love of self which is good and useful as long as it is subservient to heavenly loves. So it could be with the bronchial arteries, which are good as long as they serve the lungs for growth and health, but which would be evil if they took too much blood and deprived the other parts of the body.

132. The connections between the blood vessels of the bronchial system and those of the pulmonary system are believed to permit a "leak" of only one or two percent of blood back to the "wrong" side of the heart (Dejours, 1981). The existence of these connections may correspond to a childish state when the understanding is biased by the will and does not work with precision. Such a state is all too common among adults, of course, but it is nevertheless childish. This also agrees with anatomical observations, which show that such connections are fewer in adults than in the very young. (My earlier suggestion (Berridge, 1979B), which was that the connections illustrate how readily the affection for knowing develops into the affection for truth, agrees with the one now put forward, inasmuch as the affection for knowing begins in the childish state and can only gradually become the affection for truth.)

133. The bronchial arteries do not disappear when growth ceases. The living tissues in the lungs still need nourishment, cleansing, refreshment and the replacing of worn out parts by new growth. In the same way, the understanding needs to be continually refreshed; hence the need for recreation and change. These considerations show that the first conjunction of will and understanding is not limited to childhood. It happens all the time. We shall see later (No. 153) how the other conjunctions improve the first and facilitate each other.

134. Since the product of this first conjunction is an affection (which is of love, hence of the heart), we assume that it corresponds to the blood vessels which are being produced in the lungs in accordance with their growth.

135. It is interesting to express some of the phrases of proposition (vi) in DLW 404 in more common if less exact words: "affection for knowing" can be "wanting to know," "affection for reasoning" can be "wanting to know and to argue" and "affection for forming conclusions on matters in which he takes delight" can be "deciding what he wants to do." So we have a series typical of the young child: wanting to know, then to know why and argue, and finally to do something. This series at its own level is very like the series of propositions vi, vii and viii, and we are reminded that in spiritual things the parts are an image of the whole (see for example HH 58).

The aorta and its branches that effect and control breathing correspond, in part, to affections that activate conscience or perception

136. That they correspond to affections is clear from it having been said so many times that arteries "belonging" to the heart correspond in that way.  The activation of conscience corresponds to all the parts that cause the chest to expand and draw air into the lungs. The carotid bodies, their  nerve connections through the medulla oblongata and the various obedient muscles (see no. 124) must all be part of this system. It is said in part because all the blood courses through the aorta and supplies all parts of the body, which, of course, includes many that have nothing to do with respiration except their dependence on it.

137. With respect to the second conjunction we read in DLW 404 that it "comes through an affection for understanding from which springs perception of truth," and a little later, "everyone has as much perception of truth as he has affection for understanding." From the rest of this paragraph we deduce that anyone of sound reason who loves to understand is able to perceive truth according to the measure of his love. This suggests further that here perception means not that special faculty which is confined to the celestial genius, but something we all have. (On the other hand one may argue that love in the spiritual man is so weak that his perception, which depends on love, is of a different order of magnitude, though of the same kind, as that of the celestial.)

138. In examining the physiological correspondence that I have suggested for this, the second conjunction, we bear in mind that the conjunction depends on an affection, or a will, wish, or desire to understand. How similar is the longing for understanding to the longing for a deep breath of fresh air! The invigorating air enlivens the body as the spirit of the Lord renews the soul of man. But breathing must continue all the time. The blood must be pumped continually to the head through the carotid arteries and past the carotid bodies which in turn will continually "inform" the nerve centres whether more or less air is needed. Perhaps we will not be going far astray if we see here a correspondence of the continual vigilance of conscience. For the love is continually urging many activities and in the regenerating man all the impulses of love cannot avoid being examined to see whether they are acceptable to the conscience. As the "blood" of the spirit is on its way to the "head" we can think that it is being monitored by a higher faculty with celestial affinities. As the carotid bodies are in the neck they might correspond to a faculty that partakes of both the spiritual (chest) and celestial (head) and the longing to understand genuine truth must be an
urge from something higher or within.

139. Conscience comes into the picture quite readily, for the product of this second conjunction is "perception of truth," and conscience is a species of perception (AC 2144:3). Now, however, we find that the branches of the bronchia are the things which correspond to perceptions and thoughts from affections for truth (DLW 405). Are these latter perceptions and thoughts different from that perception of truth arising from the second conjunction which is the one we are trying to understand now? They may well be different. We are suggesting that conjunction No. 2, i.e., through affection for understanding, corresponds to the whole operation of the system which controls the breathing. This system ensures the proper working together of the heart and lungs. Thus it is a conjunction. On the other hand, the perceptions and thoughts from affections for truth are mentioned later (DLW 404: viii) and presumably follow the others. So this later perception is different, but the former is equally important, for if the lungs are to breathe there must be ducts for the air to get in. Believing the air corresponds to the Divine Spirit,[9] we can imagine that the ducts leading it in must correspond to a kind of perception other than that which makes man aware of his need. Although there is only one life it is received at many different levels. It is all a highly complex process forming a continual cycle. The life which is within activates the monitoring system which indicates a demand (or a satisfied demand) for more life. Nevertheless it can be conceived of as one process.

140. In this way the physiology extends our ideas of conscience and perception. The product of the second conjunction between the will and the understanding is "perception of truth." We find this concept difficult to grasp when it refers to the celestial genius, but the perception everyone has is easier to apprehend. If we accept the suggestion that the corresponding product in the body is not merely an organ, nor even the use of an organ, but a whole integrated system of control in addition to the organs mentioned (the bronchia), we can possibly enrich our ideas of perception.

141. Just above, "affection for understanding" was paraphrased by "desire to understand." It is a striking point in the correspondences that the stimulation of the carotid bodies and other sensory organs by vitiated blood produces a desire to draw breath - on occasion an irresistible urge. So we see a perfect parallelism when a man, feeling his lack of truth, draws in the Divine breath or Spirit. For him to have spiritual life he must do this continually, drawing in the breath of God more or less deeply according to his need. But this will do him little good if the air fails to reach the spiritual "air saccules" where it meets the "blood." His perception of truth will be sterile unless he puts it to use. And the difference between a sterile perception of truth and a fruitful one is like the difference between shallow and deep breathing. The breathing gets deeper when the lack of air is felt. The perception of truth gets keener when its absence is troublesome. The lack of air for the body is felt more and more as exercise or work (i.e., application to use) is undertaken. So also as the life of the spirit expresses itself in uses, the soul (will joined to understanding) is stimulated to draw Divine Truth deeply into itself so that it may purify and refresh the blood of the spirit. Here, however, we are already thinking of the third conjunction, for it is from this that thoughts of wisdom and hence of use are born. The affection leading to this third conjunction seems to correspond to the pulmonary arteries, to which we now turn.

The pulmonary arteries correspond to affections that complete the means whereby new life from the Lord can flow into the mind

142. The pulmonary arteries form the third arterial system of special importance to the lungs, so that we consider now how they are related to the third conjunction. Of this we read, "The third conjunction comes through an affection for seeing truth, from which springs thought" (DLW 404, proposition viii). From what follows in that paragraph one is led to infer that the thought referred to is not necessarily merely that kind which shows up in bodily speech and action when anyone is in the company of others. This latter thought is contrasted with the thought a man has when an affection for understanding leads him to perceive truth. This kind of thought is called thought of the spirit or meditation. It also falls into the thought of the body but not obviously so, for it is above thoughts which come from memory and it makes use of them for conclusions or confirmations. It is said to look down on them, but naturally it also influences them greatly in selecting from them according to the use required.[10]

143. It was mentioned above (No. 135) that in spiritual matters each part is an image of the whole (HH 58). It is the same with the affections corresponding to the pulmonary arteries. The fact that the branches of these arteries follow one another so closely suggests that the corresponding affections may also follow very closely, and form a triad like the three conjunctions. The affections for truth, for understanding, and for seeing what is understood are the result of love entering the understanding. It would appear that they follow one another as closely as do the branches of the pulmonary arteries in the lungs. For consider the affection for truth; does anyone love truth and not wish to understand it? When he understands it, does he not love to turn it over in his mind and see it from different points of view? Hence it can be seen that the third conjunction includes elements of the former two.

144. Remembering that thought is the product of this third conjunction, we now come to consider the correspondences and note that thought corresponds to the "minutest air cells, which are receptacles for the air used in breathing" (DLW 413). We read further that thought flows from conscience and it is "little else but an unfolding of the things that are of conscience and thereby the partition of them into ideas and then words" (AC 1919). This unfolding and partitioning reminds one of the repeated branching and dividing of the bronchia until they end in the innumerable "minutest air cells."

145. I have suggested that the affection leading to the third conjunction corresponds to the pulmonary arteries. These undergo repeated branching and dividing more or less as do the bronchia until they end in the minutest capillaries in the surfaces of the minutest air cells. The agreement between the correspondences of the affection (pulmonary arteries and derived capillaries) and those of the thoughts, arising from the conjunction the affection produces (the minutest air cells), is seen in the close association of the two structures. Here we have the closest possible intimacy belonging to the marriage of the heart and lungs. In these minute air cells the blood is separated from the air by the thinnest of membranes; here the capillaries are very densely packed, yet in a single layer, and their walls are exceedingly thin (0.2 micron, i.e. 0.0002 millimeters). Everything is arranged to facilitate the exchange of gases between the blood and the air in the lungs. We see from this how every thought is a marriage of will and understanding: as the oxygen refreshes the blood so the truth enlivens the love, and this takes place in every
minutest thought. The blood can receive oxygen only in these minutest air cells. Similarly, love can be enlivened only when truth is present in every least thought. Not that we must think of nothing but doctrine, but that the truth, which is the inflowing of the Holy Spirit of the Lord, gives life to the mind through every minutest thought. Yet there are many thoughts that seem to have little or nothing to do with love, wisdom, or even facts and common sense. Can they correspond? It seems that they can, for during quiet respiration, that is, in the absence of muscular exertion, some parts of the lungs move only slightly, and less than a tenth of the total capacity is emptied and refilled with fresh air. The new air mixes with the stale air remaining, but obviously some air saccules get fresher air than others, and probably some remain closed until the demand increases (Cotes, 1963, p. 415). So we have many thoughts which are not matters of conscience or perception but which can become so during occasions of joy or stress that correspond to muscular exertion.

The understanding of the simultaneous workings of the mind is facilitated by the imaginary separation in time of circulatory functions that are simultaneous

146. We may now reiterate the products of the three conjunctions, namely, affection of truth, perception of truth, and thought. In DLW 404 (proposition viii) these three are repeated in different words which help the reader to grasp the meaning:

It first begets affection for truth, then affection for understanding what it knows, and finally affection for seeing in bodily thought that which it understands.
Since this last is used for conclusions and confirmations, it is the driving force within wisdom of speech and charity of action.

147. The psychology of the three conjunctions is said to be "but dimly seen by those who are unable to perceive the mind's workings separately…" because "the mind's workings are simultaneous in the thought with those who have both affection for truth and the perception of it…" (DLW 404: viii).
    This difficulty can be diminished by studying the corresponding heart and lungs, where several processes occur almost simultaneously. We  separate them in order to understand them, and as they are relatively easy to consider separately, it may be worthwhile to re-examine the subject from this point of view, although some repetition will be involved.

148. We have first the bronchial arteries in the embryo. By their means the lungs and all accessory tissues are nourished and are able to grow. Also the bronchia, their branches, and the minutest air cells are formed. These last two would correspond, respectively, to means aiding perception, and to thoughts; but as they are not yet in use, they cannot correspond. Just before birth the whole system is ready, but not working. From this we may deduce that the betrothal between the will and the understanding produces in due order all the faculties of the future mind, and facilitates their growth, but not their activity. Obviously, mental growth continues for a long time after activities begin, just as the heart and lungs keep pace with the growth of the body. As the embryo itself has no will and no understanding, it may seem difficult to accept this summary explanation. Nevertheless, there must be some form of correspondence for these things to come into existence. We cannot doubt that the correspondence is with the will and understanding of the angels who are close to the embryo, and perhaps with those of the mother if she is angelic. We remember also that spiritual matters are not bound in with our bodily, four dimensional space-time continuum. What seems future to us is present with the Lord, and, by derivation, to some extent with angels also. What appears as future can act as a cause in our natural sphere, besides the immediate influx from the Lord.

149. We have, secondly, the carotid bodies together with similar sensitive structures and the nerve centres and muscles through which they operate. Through their means the machinery which has been formed will be animated and controlled. Knowledge will be brought to life, truth will be perceived as something beyond mere fact, but thought in accordance with the truth perceived waits on the third conjunction.

150. We have, thirdly, the pulmonary arteries (The third signifies completion) in full flow after birth. The difference is fantastic! It is the dawn of life, the baby's first cry; it is Man, the work of the Creator. Only now can the other two conjunctions operate fruitfully. Growth and control are meaningless until use follows. The physiology shows it so clearly. Now at last the pulmonary arteries can convey the full flux of blood to the millions of air cells whereby the blood and thence the whole body will receive all the oxygen it needs, and eliminate the carbon dioxide that would poison it. Similarly when the will, as a receptacle of love from the Lord, completes the three stages of its conjunction with the understanding, as the receptacle of wisdom from the Lord, the man can truly begin to live.

151. What is worth contemplating more closely is that, as the whole of the blood must circulate in its turn through the lungs, so all the activities of the will must be subjected to the understanding for purification (corresponding to the elimination of carbon dioxide) and for potentiation (corresponding to the absorption of oxygen). All the blood from the lungs comes back to the heart to be pumped at higher pressure to the heart muscles themselves as well as to the whole body. This must mean that when the understanding has invigorated the thought, the will itself receives invigoration, enabling it, in turn, to fill the whole mind with vigour.

152. What is also very remarkable is that when this refreshed blood is returned to the heart and re-distributed, it is continually assessed to determine whether its refreshment is commensurate with requirements, and if not, higher centres make the necessary adjustments. Similarly, in the mind or spirit, the activities performed by the will with the aid of the understanding are continuously observed by the conscience or perception to determine whether they conform to the standards required. If they do not, the understanding is further stimulated, or, alternatively, commanded to rest. From the correspondence it is clear that conscience and perception are far more than can be put into two simple words. They must be complex sensing and controlling systems through which the Lord works (see for example AC 875).

After sequential development in due order, the three affections, conjunctions, and offspring can occur repeatedly as rapid cycles or spirals whereby the mind develops further and becomes more useful

153. We notice now that although the three conjunctions of heart and lungs follow over a period of time in the embryo and young child, they become simultaneous after birth. So with the spirit; each conjunction must be properly effected in order and its offspring may be produced. After that, affection of truth, perception of truth, and thought follow so closely as to seem simultaneous, but it seems easier to imagine that they form a cycle which can be repeated with great rapidity. The short time required for the circulation of the blood emphasizes this point. A thought will stimulate the affection for truth so that a further perception arises, whence new thoughts originate, and in a few seconds an entirely new mental condition prevails. Changes continue! Thought as an end in itself is useless. The correspondence of heart and lungs by themselves is obvious. The rest of the body is needed for use. The will must be determined into action, but in such a way that "whatever is done from this appears as if by the man's will, but is really done by the Lord" (AC 875).

The correspondence of a new will (or heart) given through regeneration requires further study

154. Throughout this chapter we have assumed that we are dealing with a regenerating man, but in many places we are told that regeneration involves the giving of a new will in place of the old one which is irredeemably evil. The lack of obvious reference to this part of the subject in DLW poses a serious problem. This problem is considered in the next chapter.

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5 It is important to distinguish between the bronchia which are air tubes and the bronchial arteries and veins which are blood vessels. Failure to do so can lead to confusion. The mere omission of the final letter 'l' can easily happen as a misprint. This seems to be the case in the 1969 Swedenborg Society edition of DLW (p. 184).

6 Connections of both blood and nerves to the muscles of the ribs and diaphragm are very important, but they are not essential for survival because either the ribs or the diaphragm can be used for breathing, when partial paralysis occurs (as in poliomyelitis, for example) even muscles of the neck can be used to draw up the ribs and expand the lungs.

7 The inclusion of this route as important in the relationship between the heart and lungs is precisely a matter of fact, but it is also in harmony with the Writings, for, twice in DLW 412 the aorta only is mentioned as the source of arterial blood other than the heart (the vena cava being merely the return route), and all the arteries of the third system are branches coming from the aorta. Of course, the blood from the aorta comes from the heart, but here, coming from the aorta is contrasted with coming from the heart, because much of the blood coursing through the aorta goes elsewhere, but all the blood from the right side of the heart goes through the pulmonary arteries. This is discussed further in Section 8 of Chapter VII.

8 It is said (122D) that the 6th aortic arch of the embryo soon becomes recognizable as the pulmonary trunk, the heart being already clearly linked to the lungs. At this early stage, however, the contribution of the bronchial arteries is difficult to evaluate.

9 This correspondence may be deduced from the meaning of "wind" as explained in AE 419, for wind is nothing but air in motion. In AE 1012, however, air is said to signify thought. The signification and correspondences are harmonious when man is in order and his thoughts are from truths. In states of disorder a man will seek stale or foul air (falsities) rather than a fresh breeze. The equivalence of breath and spirit is mentioned in AC 9987, and DLW 383 as well as in AE 419.

10 The inferences here drawn are derived in part from the following details. The word "perception" is omitted from the series towards the end of proposition viii (DLW 404, 3rd conjunction) where we find "when love enters into the understanding,…it first begets affection for truth, then affection for understanding what it knows, and finally affection for seeing in bodily thought that which it understands." But we have seen that affection for understanding produces perception of truth (vii), also that this perception is the thought of his spirit, i.e., meditation (vii middle) which falls into bodily thought, but hidden or silent thought. When we compare this with the former quotation we see that the thought mentioned there is not hidden, thus the 3rd conjunction is tending towards producing effects in the natural, and as we have said, the thoughts or meditations it produces make use of ideas from the memory for conclusions or confirmations, which are thoughts of wisdom.