1. THERE have been three grand theories—hypotheses, actually—of the nature of the interaction between the soul and the body, meaning the way one affects the other and cooperates with it. The first of these is known as “physical inflow,” the second “spiritual inflow,” and the third “preestablished harmony.”

The first, called physical inflow, is based on the way things seem to our senses and on the deceptive appearances that result, since it seems as though the objects of sight that affect our eyes flow into our thinking and make thoughts happen. In the same way, it seems as though the conversations that affect our ears flow into our minds and cause ideas to form there. We could say much the same of smell, taste, and touch as well. Because our sensory organs first receive the stimuli that impinge on them from the world, and because the mind seems both to think and to will things in response to those stimuli, the classical philosophers and Scholastics believed that an inflow from our sense impressions impinged on our soul. This led them to come up with the hypothesis that the inflow between the two was physical, or earthly, in nature.

[2] The second view, called spiritual inflow (some call it “occasional inflow”), is based on the laws of the divine design. It sees the soul as a spiritual substance and therefore something purer, primary, and inward; while the body is matter and is therefore coarser, secondary, and outward. In the divine design, what is purer flows into what is coarser, what is primary flows into what is secondary, and what is inward flows into what is outward. Therefore what is spiritual flows into what is material, and not the reverse. To be more specific, the part of our mind devoted to thinking flows into our eyesight in accordance with the state imposed on our eyes by the objects we are seeing, and also imposes its own priorities on that state. In the same way, the part of our mind devoted to perception flows into our hearing in accordance with the state imposed on our ears by what is being said.

[3] The third view, called preestablished harmony, is based on plausible rational fallacies, because when the mind is producing an effect it does so in unison and simultaneously with the body. However, every deed starts out sequential and only later becomes simultaneous. Inflow is sequential, and harmony is simultaneous, as we can see when the mind thinks something and then says it or when it wills something and then does it. It is a rational fallacy, then, to insist that there is a simultaneous aspect yet deny that there is a [prior] sequential one.

These three are the only possible theories—there is no fourth. The soul activates the body, or the body activates the soul, or the two are constantly acting in unison.

12. 10 It is spiritual elements clothed in this way that enable us to live as rational and moral beings—that is, to live spiritually on this earthly level.

THE principle just established—that the soul wears the body the way we wear clothes—leads to the conclusion that the soul flows into the human mind and through it into the body, bringing with it the life that it is constantly receiving from the Lord. It therefore transfers life into the body by these means; and there, through the tightest of connections, it makes the body seem to be alive. This principle, along with the evidence of a thousand experiences, shows that what enables us to speak rationally and act morally is a spiritual element that is united to the physical, like a living force united to a dead one.

[2] It does seem as though our tongue and lips talk because they have a life of their own and that our arms and hands move for the same reason. However, it is actually our thinking, which is essentially spiritual, that is speaking and our will, which is likewise spiritual, that stirs us to action. Thinking and willing operate through organs that are thoroughly physical because what they are made of comes from the material world. The truth of this becomes as clear as day when we pay attention to the following: if we remove our thinking from what we are saying, our mouth is instantly silenced, and if we remove our will from our actions, our hands are instantly stilled.

[3] As for this uniting of spiritual and earthly realities and the consequent appearance that there is life in material things, we could compare it to fine wine in a clean sponge or the sweet liquid in a grape or the delicious juice in an apple or the fragrant aroma in cinnamon. All the enclosing fibers are materials that have no taste or fragrance of their own; the taste or fragrance is supplied only by the fluid elements that are in and among them. So if you press out those fluids, the fibers themselves are lifeless shreds. The same holds true of the organs of the body if we take away their life.

[4] It is spiritual qualities united to our earthly ones that make our rationality possible, as we can see from the analytical abilities present in our thinking. From our capacity for decency of action and propriety of behavior we can see that the same applies to our morality as well. We have these capacities because of our ability to receive an inflow from the Lord through the angelic heaven, which is the home where wisdom and love and therefore rationality and morality live. These examples let us see that we have the ability to live spiritually on this earthly level because what is spiritual and what is earthly are united within us.

After death it is much the same, though not exactly so, because then our soul is clothed with a substantial body, whereas it was clothed with a material body in this world.

[5] Many people believe that since the perceptions and thoughts of our minds are spiritual, they flow in as they are, without going through organized structures. People who dream up such things have not seen the insides of the head, where perceptions and thoughts occur in their primary forms. For example, they have not seen that there are brains there, intricately woven of gray matter and medullary matter, that there are little glands, recesses, and partitions, all enclosed in meninges and membranes, and that our thinking and willing are either sound or insane depending on the healthy or disordered state of all these elements. Likewise, we are rational and moral according to the organic shape of our mind. Without forms structured for the reception of spiritual light, our rational sight, the sight of our intellect, would have no attributes. It would be like physical sight without eyes. And so on.

18. 16 This shows us the nature of spiritual inflow, from its origin to its results.

UNTIL now, spiritual inflow has been deduced to flow from the soul into the body, but not from God into the soul and from there into the body. This has come about because no one has known anything about the spiritual world and its sun, yet that sun is the source from which all that is spiritual pours forth as from its wellspring; so people have not known anything about the way spiritual realities flow into physical ones.

[2] Since I have been granted the ability to be in the spiritual world and in the physical world at the same time and therefore to see each world and each sun, I am obliged by my conscience to make these things known. What is the use of knowing something except that others should know it as well? The one without the other is like amassing wealth and hiding it away in a chest, simply counting it and admiring it from time to time with no intention of putting it to use. This is nothing but spiritual avarice.

[3] For a full understanding of the reality and nature of spiritual inflow, though, it is necessary to know what spiritual is in essence and what earthly is, and also what the human soul is. For the reception of this brief treatise not to be hobbled by ignorance on these points, it would be beneficial to consult some accounts of memorable experiences included in the book Marriage Love. On what spiritual is, see the account in §§326–329; on what the human soul is, see §315; and on the inflow of what is spiritual into what is earthly, see §380, and the fuller treatment in §§415–422.