The Impossibility Of Spirit-matter Interaction According To The Joseph Campbell Theory

From the very beginning of our lives, we know that our mind has very different properties from our body. While some of us pondered on the differences, philosophers have already dug deep into the core of the mind-body problem. Substance dualists argued that although the mind and body are entirely different, there are causal interactions between the two. However, in the last decades, this view started to get less certain due to problems and contradictions associated with it. The entire mind-body problem may be summed up in four propositions:

1. the human body is a material thing,
2. the human mind is a spiritual thing,
3. body and mind interact,
4. matter and spirit do not interact (Campbell, 1970, p. 35).

This paper will focus on the fourth claim. I will explain Campbell’s argument regarding the problematic nature of spirit-matter interaction. Further, I will defend this argument against the objection concerning the principal possibility of finding mathematical expressions for matter-spirit interactions. I will argue that establishing a causal connection between spirit and matter is impossible because of the principal differences between the two substances and use Campbell’s empirical argument for additional support.

In the article, Campbell argues that the Pure Regularity Theory of Causes does not apply to spirit-matter interaction hence making the interaction itself either impossible or problematic. Since interaction means causation, there must be some sort of causal link between matter and spirit. If this is so, then there must not be any relations of causation between spirit and matter.

The Pure Regularity Theory puts absolutely no constraints or limitations on the nature of the bodies or phenomena. Spirit can causally influence matter and matter can influence the spirit, if and only if all the conditions of causation are satisfied. These conditions are the following. First, there should be two events, which we may call c and e. For c to cause e, they must not be too far in time from each other – e should occur simultaneously with c or immediately after it. Essentially, causation can extend to much greater periods, however, such cases feature a causal chain consisting of multiple causal links, rather than a single causal link. And for defining what causation is, we should only stick to describing the individual causal link. As c and e should be close in time, they should also not be too far in space from each other.

Also, to rule out the possibility of coincidence, the whole class of C events, which are relevantly similar in the context of the interaction to c, must be followed by events from class E, which is comprised of events relevantly similar for the interaction to e. For the two events to be causally connected, there must exist such a class of sequences (C-E in the context of the definition above) of which this connection is an example (like c-e). As we can see, the Pure Regularity Theory of Causes is extremely broad and general in its description of causality. It did not provide us with how it can be applied to explain the causal connection between the spirit and matter. Therefore, either causation is impossible or at least not conforming to our understanding of causations.

One of the possible objections to Pure Regularity Theory is our scientific understanding of various processes, which also demands an additional explanation of how the causal link works to postulate causality. In the sciences, people are usually not content with the statement of causality as mere sequences of events. The mechanism of why this causal connection occurs is also demanded to state causality. For instance, we do not indulge the explanation that applying current to a light bulb causes it to emit light. We also want to know the “how” and “why” the light bulb changes from one state to another. However, this mechanism that we want to know is itself a chain of events. Every mechanism of some connection can be broken down into fundamental connections, in which no other event between the cause and effect exists. For these fundamental connections, we are unable to produce any further explanations.

In the case of the light emitting from the light bulb, it is because electrons dissipate energy as heat while running through the glower, and at high temperatures bodies emit light. However, if we delve deeper into the problem, we will find that there is nothing between the cause and effect that would fill this explanatory gap. While we are unable to explain the mechanism of the fundamental connections, we must simply accept them as laws of physics but we may describe them in mathematical terms. Particularly, we may investigate the ability of bodies to emit light at different temperatures and formulate equations describing the relationship between light emission and temperature. Hence, in the matter spirit connection, either the causal relationship is a fundamental relation that abides by the Pure Regularity Theory of Causes or it is a complex of fundamental relations that can be explained in terms of mechanism additional to the regular sequence. In brief, a causal relation must either have a mechanism or be possible to describe in mathematical terms.

The spirit-matter interaction is problematic because it has neither a mechanism nor admits a mathematical expression. While the mechanism of the brain affecting the body can be made clear by neuroscience, the mechanism of spirit affecting something material is not. Due to the nature of the spirit, we may not observe it externally, and the only insight we might have into it is through the window of consciousness or introspection. And as far as our mental experiences go, the act of body-mind interaction does not have a mechanism. There is no explanation of why does hitting a finger with a hammer causes pain in terms of spirituality – it simply does. Hence, if matter-spirit interaction does not have a mechanism, it must be a fundamental relation. However, if the causal relation is fundamental then it must be explainable in mathematical terms.

Physics is by a large amount the science about fundamental interactions – it identifies them and seeks to express in mathematical terms. In the case of spirit and matter interaction, we have no mathematical expressions for the functions of the mind. We cannot express concepts and entities of the spiritual world in the physical terms, this is why we have no mathematical descriptions of the relations between these processes. Hence, the relationship between matter and spirit neither has a mechanism nor is a fundamental relation, then it is not a causal relationship. The causality considerations discussed above are all we currently know about causality. If the relationship between matter and spirit is not causal in our current understanding of causality, then either it is impossible, or a new paradigm needs to be developed for causality.

Campbell’s argument is successful because it contains no errors in logic and operates with the most basic entities. To defend this argument, I will consider and respond to several objections targeting different parts of this argument that may seem problematic.

Although the argument states that we have no mathematical descriptions of mental events, it does not rule out their principal possibility. While fear certainly doesn't have length or weight, it has strength or intensity, and intensity can certainly be quantified. In fact, it is already being quantified in hospitals when people rate their pain on the scale from 1 to 10 and the Glassglow Coma Scale has long been in use to testify the patient’s level of consciousness. The same may be done with other aspects of mentality. Even though we do not have equations describing the interaction between mental and physical phenomena. Future research will quantify this fundamental relationship between the mind and body.

While Campbell’s argument may seem compelling, it has a large problem of not addressing the entirety of the concept of mathematical description and principal differences between spirit and matter. While spiritual objects can be quantified, this quantification is not universal and explicit. When we are speaking about mathematical descriptions, we are speaking about “what” and “where” of the relation. Each of these aspects needs to be described mathematically to produce a complete explanation of the fundamental relation. This at least must be possible. The problem with the matter-spirit relation is that producing such a description of the interaction does not seem to be possible at all. If we take the light bulb example employed above, all the aspects of the fundamental relation between temperature and light emission may be described mathematically.

Particularly, we may express in equations the essence of the relation – i.e. which temperature corresponds to which light color and intensity. The same goes for the spatial description of the phenomena – where does the shining occur, how temperature and light emission are related spatially, and in which direction the light is emitted, all of them can be described using equations. The same things cannot be made for spiritual phenomena like fear. First of all, mental phenomena cannot be quantified precisely and reliably. While the light intensity emitted by a bulb can be directly measured with great accuracy, it is not possible for mental phenomena, as our tolerance for pain varies from person to person. We may certainly assign approximate grades to different spiritual phenomena, but essentially we are still gathering responses from our bodily sensations. In the case of hitting your finger with a hammer, there is not a standardized scale for pain in use. In fact, in more recent researches, we are measuring the firing rate of neurotransmitters within the spinal cord to determine the levels of pain.

Another problem is that it is not explicit – the same physical activity may result in mental phenomena of different magnitude. Particularly, pain from hitting one’s finger with a hammer with the same force will greatly depend on the mood of the person and many other factors. Moreover, when we come to the problem of “where”, we stumble upon an even greater problem. If spiritual things have no exact location and size, then how can we connect them with the material terms? If mental phenomena have no position in space and no extension, then there is no place to which we can attach these mathematical explanations. It seems that this problem is irreconcilable in the sense that spiritual and material things cannot causally interact in terms of our current understanding of causality.

The spirit-matter interaction is problematic exactly because of the principal differences between the two. If matter and spirit can interact, then there should be some link between them – something that connects the two realms. Although multiple answers were suggested for this problem, starting with certain brain parts and ending with god, neither of them is satisfactory. Neither of them provides a comprehensive explanation of how the very border dividing the two worlds may be crossed. In Campbell’s terms discussed above, this may be expressed as an impossibility of the mathematical description of the fundamental connection that crosses the border. If neither of the two can cross to the other side, then the interaction between them is pretty much impossible.

This concern is further elevated by Campbell’s empirical argument for the same conclusion. Particularly, Campbell suggests that the connection between body and mind in practice is far from mysterious. Each of us knows this relation well from everyday life, as each of our actions is the causal influence of mind over the body. Moreover, from the physical side of the issue, the situation also seems to be rather clear. We at least approximately know the mechanisms that govern the work of the brain and body. We know how electric signals from the brain travel to our organs and make our cells operate differently. There is nothing mysterious or problematic in the interactions between our brain and body. However, there are problems and mysteries in the way in which spirit and matter interact. And since we all clearly understand that the mind has at least something to do with the brain, considering all said above, the causal interaction between matter and spirit seems outright impossible.

Campbell offers a compelling argument against the possibility of causal interaction between matter and spirit. The considered objection was refuted, and it has been argued that the interaction of spirit and matter seems principally impossible. This, however, leaves us with other questions. If matter and spirit cannot causally interact, then it must be the case that there is no such thing as spirit because only matter exists. All this mind-body debate ultimately seeks to explain such a complex thing as the mind. Refuting certain positions, we can focus on those considerations that seem more fruitful for our search of the truth.