Does the Causal Closure Argument Close off Dualism?

        In contemporary analytic philosophy of mind, the causal closure argument is the main argument for

physicalism. Indeed, it is considered so powerful that there are few other arguments for physicalism

employed by physicalists. Is it decisive, though? In this essay, I will argue that it is not. I’ll begin by

explicating the causal closure argument and how it is supposed to refute dualism. I’ll then present and

motivate hylomorphism by comparing it to the contemporary notion of grounding and then arguing that

hylomorphism is still more metaphysically precise than grounding. I’ll then argue that it enables the

dualist to evade the conclusion of the argument, while maintaining the causal closure of the physical and

also briefly engage with epiphenomenalist worries. I’ll present an alternative dualist response and then

argue that the hylomorphism response is superior. My central thesis is that hylomorphism, particularly the

notion of formal causation, provides the dualist with a plausible metaphysical framework with which to

avoid the conclusion of the causal closure argument.

The causal closure argument uses the intuition that physical events must only have physical causes to deduce that physicalism must be true (Stoljar, 2021). The thought behind this is that if there is an entity of type A and type A is radically if not infinitely distinct from type B, then entities of type B cannot causally interact with entities of type A. Applying this philosophy of mind, since physical entities are radically different from mental entities, as physicalist and non-physicalist alike would grant, then physical entities cannot causally interact with mental entities and vice versa. Also, if physical entities are all that is necessary to explain physical events, which follows from the above intuition, then positing substantially distinct mental entities to explain physical events in the brain is unnecessary. David Chalmers presents a plausible version of the captures that core intuitions of the physicalist:

(1) Phenomenal properties are causally relevant to physical events. 

(2) Every caused physical event has a full causal explanation in physical terms. (3) If every caused physical event has a full causal explanation in physical terms, every property causally relevant to the physical is itself grounded in physical properties. 

(4) If phenomenal properties are grounded in physical properties, materialism is true.

(5) Materialism is true. (Chalmers, 2016)

The fundamental metaphysical problem for the dualist that follows from this argument is the worry of causal overdetermination, which is when two efficient causes only produce one effect. The worry would be that positing distinct mental entities which could have physical effects would causally overdetermine physical events in the brain since each event would have two efficient causes. The absurdity would be that it seems like one cause, the mental cause, is inefficacious since it does not produce a distinct effect from what the physical cause produces. It also seems explanatorily vacuous to posit a second mental since the physical is sufficient to explain the physical event. 

Despite the power of this argument, I think there is space for the dualist to plausibly reject the conclusion of this argument. Particularly, the notion of causal relevance is vague enough that the dualist could place his mental entities within this realm and I believe hylomorphism helps him to do this.

Hylomorphism is the thesis that material objects are composed of form and matter where form is the principle of actuality in things and matter is the principle of potentiality in things (Ainsworth, 2015). Going a bit deeper, matter can be thought of as the aspect of things which allows them to change and form can be thought of as the aspect of things which provides structure to them. One of Aristotle’s main motivations for formulating this distinction is to respond to Parmenides's argument against the possibility of change. Aristotle thinks that one must divide being into two fundamental categories, actual being and potential being. Actual being is the way a thing is in reality whereas potential being is the way a thing could be. He makes this distinction in order to account for change, which he sees as the actualization of a potential. To explicate this with an example, fire makes cold water move from being potentially hot to being actually hot. For Aristotle, form and matter are the entities which correspond to actual and potential being and so allow for the possibility and reality of change.

To provide some support for this thesis, let me present Kit Fine’s has a simple, yet powerful argument for hylomorphism:

(1) The statue is badly made 

(2) The piece of alloy is not badly made 

(3) Therefore, by Leibniz's Law, the statue and the piece of alloy are not the same. (Fine, 2007)

Fine asks us to suppose that there is a statue made out of a metal alloy which is poorly made. He argues that it makes little sense to say that the alloy itself is poorly made since there could be other instances of that alloy which are not per se poorly made. Rather the statue is poorly made. This leads to an interesting conclusion: what enables us to predicate ‘poorly made’ of the statue cannot be material otherwise we would have to say that the alloy is poorly made, but it is the statue that is poorly made. Therefore, there must be something about the statue which is non-material which enables us to say that it is poorly made. This aspect of the statue is form: a non-material principle which actualizes matter. The reason there must be something, an entity, in the statue that enables us to say that the statue is poorly made is because if there were only the matter of the statue the property of being ‘poorly made’ would not have anything to hook onto, so to speak, in the statue since the matter of the statue is not poorly made. If there were no immaterial aspect of the statue, then there would be nothing in the statue which would enable us to say it is poorly made. So there must be some immaterial aspect of the statue, which is what Aristotelians call form.

It is important to note the connection between hylomorphism and Aristotle’s four causes: material, efficient, formal, and final. For the purposes of this paper we need only discuss the first three. With respect to material objects, the material cause is simply “that out of which” the thing is composed, the formal cause is “the account of what-it-is-to-be” or that which grants conceptual content, actuality, to matter, and the efficient cause is “the primary source of the change or rest” or that which combines matter and form (Falcon, 2019). One can think of a formal cause as somewhat analogous to the contemporary notion of grounding. Just as under grounding, grounds do not cause events, so formal causes do not cause events in the sense of efficient causality, but rather entities which are more fundamental than the things which depend on them, namely matter. Moreover, just as grounding explanations dependency relations where if p grounds q then p is a precondition for q even if p is not a cause of q, so do appeals to formal causation point out relations where p does not cause q, in the sense of efficient causality, but rather a precondition of there being any q at all. Formal causation can be thought of as a more specific grounding relation because the precondition for q, which we can say would be a certain mental state in this case, will be the form. This is more metaphysically precise than simply appealing to grounding because formal causation identifies a certain metaphysical entity, the form, which can only ground certain truths, namely truths about actualization.

These are important distinctions to draw out because the causal closure argument only acknowledges the level of efficient causality. Aristotle’s other causes, especially his notion of formal causality, are called ‘causes’ in a very different way than contemporary proponents of the causal closure argument think of the term ‘cause.’ This fact is where the vagueness of “causal relevance” can be of help to the dualist as long as he is willing to utilize the hylomorphic framework. 

Aristotle’s notion of formal causality can be considered causally relevant without challenging the fact that on the level efficient causality physical events have full explanations in terms of physical causes. The phenomenal properties which are causally relevant to physical events should not be seen as efficient causes, but rather formal causes. For example, if the phenomenal property of being in pain is causally relevant to someone removing their hand from a fire, the hylomorphist can say that the phenomenal property is a formal cause in that it actualizes the matter of the brain in a new way, however it does not cause a series of physical events in the brain body resulting in the removal of one’s hand. To use more Aristotleian language, In this case, the phenomenal properties are causally relevant since they ground certain actualities of the brain and are the preconditions for there being any physical events in the brain at all, but do not themselves cause physical events. Moreover, those who find the epiphenomenalist position to be problematic need not find those worries in this account because the epiphenomenalist does not have a way to ground the causal efficacy or relevance of phenomenal properties while the hylomorphist has a way to ground the causal relevance of phenomenal properties. Since these phenomenal properties are located in a higher, more fundamental metaphysical level than efficient causation, which would be the level of physical caution, these properties can be causally relevant while not being causes in any problematic sense.

One might object that formal causation is simply another form of efficient causation in disguise so it does not help the dualist at all. They might say that when the form actualizes the matter it is causing it to change. After all, the form does actualize the matter and so it does seem to change it. However, if the matter changes as a result of the form, it seems that there would be a case where an immaterial entity causally interacts with a material one. If this is the case, the hylomorphic dualism is just as plagued by the causal closure argument as other forms of dualism are. 

This objection, however, fails because it misunderstands the relationship between matter and form. It is certainly true that under hylomorphism form actualizes matter, form does not change matter in the strict sense because matter cannot exist apart from form and change requires a substrate which is the subject of change. However, matter could not be such a substrate since it would have to possess some being apart from form in order to be a subject of change, but this is impossible under hylomorphism. Rather, what effectuates change on hylomorphism are efficient causes, which, in material objects, consists of form-matter composites. The preconditions for these efficient causes, then, are form and matter and thus formal and material causation. Furthermore, since matter cannot exist without form, form can be thought of as a precondition for there being matter as well. So, it is better to think of the relationship between form and matter as one where form grounds matter rather than one where form causes matter. Moreover, since the properties of the form are a precondition for efficient causation rather than physical causes in themselves, those properties need not be causes themselves in order to be involved in explaining physical events. Given this, it seems that hylomorphism can, indeed, help the dualist evade the consequences of the causal closure argument. 

Still, there are other dualist responses to the causal closure argument. I will examine the response by Frank Jackson and Phllip Pettit.

In “Causation in the Philosophy Mind,” Frank Jackson and Philip Pettit argue that “of functional properties” can be thought of “as a more complex and general case of dispositional properties” and use this to argue how content can be causally relevant, but their reasoning can also be used to show how qualia can be causally relevant (Jackson & Pettit, 1990). For clarity, a dispositional property is one “that provides for the possibility of some further specific state or behaviour, usually in circumstances of some specific kind” (Mumford, n.d.). Jackson and Pettit give examples of how “we are often interested not merely in how something in fact came about but also in how it would have come about” (Jackson & Pettit, 1990). Jackson and Pettit attempt to give examples of where this is this case:

The reason being a good conductor of electricity is causally relevant to Mary's death is that it did not matter (within reason) what the categorical basis of that disposition was, for provided the causal role definitive of good electrical conductivity was occupied by a state of the ladder she would have died. (Jackson & Pettit, 1990)

They say this “is how the content properties may be causally relevant” (Jackson & Pettit, 1990). These content properties provide us with an account of not merely how a certain effect came about but also “what would happen in addition to what did happen” (Jackson & Pettit, 1990). 

Jackson and Pettit apply this account to explain how content properties can be causally relevant, but this same reasoning can be applied to phenomenal properties. Using their account, if I drink a cup of coffee, the phenomenal properties involved could account for my liking coffee, which would be the dispositional property accounting for why I choose coffee over tea, even though both have caffeine. In this case, the categorical property, coffee or tea, is somewhat irrelevant and so what accounts for my choosing coffee is the dispositional property, which, in this case, is the phenomenal property of me knowing what it is like to taste coffee.

Jackson and Pettit’s account is interesting and I even say that it is compatible with hylomorphism, however I think we should prefer the hylomorphic response because it is more metaphysically precise. Hylomorphists often hold that there are dispositional properties as well, though they would often speak of these properties in terms of teleology, and so this part of their account is perfectly compatible with the hylomorphic response. Their account, however, does not locate these disposition properties within a specific entity. Hylomorphism, however, does locate these properties within the form and so has an added level of metaphysical specificity which Jackson and Pettit’s account lacks. 

It is interesting to note that Jackson and Pettit’s view of dispositional properties seems to allow the view that these disposition properties can be thought of as preconditions for certain causal outcomes. This is just as the hylomorphic account says that form, and the phenomenal properties it has, are a precondition for efficient causation rather than an efficient cause itself. Again, though, this is a place where the hylomorphic account provides a deeper explanation than Jackson and Pettit’s account. The reason form is a precondition for efficient causation is because form is an entity which only enters into certain kinds of grounding relations. From Jackson and Pettit’s paper, it is not clear whether they think dispositional properties explain the causal relevance of content properties in terms of grounding relations, or whether these dispositional properties can enter into standard causal relations. In sum, the hylomorphic response to the causal closure is more metaphysically precise than Jackson and Pettit’s response and so while there are some compatibilities between their response and the hylomorphic response, the hylomorphic response should be preferred.

In conclusion, the causal closure argument is the primary argument for physicalism and has made physicalism the default position in contemporary philosophy of mind. Thus, dualism has been on the defensive for several decades because of the force of this argument. However, I have argued that the power of this argument has been overstated. I have shown how the dualist can evade this argument by appealing to hylomorphism, particularly the notion of formal causation, and showing how phenomenal properties can be causally relevant in virtue of being aspects of the form. I have responded to Jackson and Pettit’s response to the argument and shown how the hylomorphic response gives a more detailed, metaphysically robust response to the physicalist. In sum, I have argued that dualists need not feel threatened by the causal closure argument, as long as they embrace hylomorphism.

Works Cited

Ainsworth, T. (2020, March 25). Form vs. Matter. Stanford Encyclopedia of Philosophy. Retrieved October 22, 2022, from https://plato.stanford.edu/entries/form-matter/

Chalmers, D. J. (2016). Panpsychism and Panprotopsychism. Panpsychism, 19–47. https://doi.org/10.1093/acprof:oso/9780199359943.003.0002 

Falcon, A. (2019, March 7). Aristotle on Causality. Stanford Encyclopedia of Philosophy. Retrieved October 26, 2022, from https://plato.stanford.edu/entries/aristotle-causality/#FouCau 

Fine, K. (2006). Arguing for non-identity: A Response to King and Frances. Mind, 115(460), 1059–1082. https://doi.org/10.1093/mind/fzl1059 

​​Jackson, F., & Pettit, P. (1990). Causation in the philosophy of mind. Philosophy and Phenomenological Research, 50, 195. https://doi.org/10.2307/2108039 

Mumford, S. (n.d.). Dispositions. Routledge Encyclopedia of Philosophy. https://doi.org/10.4324/9780415249126-n116-2 

Stoljar, D. (2021, May 25). Physicalism. Stanford Encyclopedia of Philosophy. Retrieved October 22, 2022, from https://plato.stanford.edu/entries/physicalism/#CaseForPhys