An Argument Against Supernatural Causation

[Caecilian]

An interesting and I think sound philosophical argument that indicates that immaterial or supernatural causation is incoherent nonsense.


1. Introduction

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The following is an argument against the possibility of supernatural causation. Its a simplified version of chapter 3 of Jaegwon Kim's book Physicalism, Or Something Near Enough (Princeton University Press, 2005). The argument as presented by Kim is 20 pages long, so a great deal has been necessarily left out. If you're really interested, you could check out the original, but be warned: the book is serious philosophy written for an academic audience, and it ain't easy reading.

Some preliminaries:
- All references and quotes are to the original book by Kim unless otherwise stated.
- Following a discussion with purple rabbit, I'll be using the word 'supernatural' instead of Kim's 'immaterial', and 'natural' in place of 'material'.
- Although I think that Kim's argument against supernatural causation is sound, it doesn't follow that I agree with Kim's positions on other philosophical issues.

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2. Cartesian Dualism

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Kim's target is Cartesian Dualism- the view that minds are supernatural, and that have causal relationships with phenomena in the natural world. In the Cartesian position, supernatural phenomena such as minds have none of the physical attributes of natural phenomena. Critically, this includes spatiality. For Descartes and his followers (e.g. the theologian Swinburne), minds do not have a location in space.

Cartesianism is industrial-strength Dualism. As Kim notes (pp. 72-73), more popular forms of Dualism attribute at least some natural properties to supernatural phenomena. But as we'll see, abandoning the strict philosophical Dualism of Descartes for something more natural doesn't help the Dualist position.

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3. Understanding Causation

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If we say that something causes something else, then we are describing a relationship that pertains between the 2 phenomena. But what sort of relationship is it? What sort of linkage are we referring to? A short thought experiment (pp. 78-79) will help.

Lets say that 2 people, Arthur and Brett simultaneously fire 2 identical guns. Arthur kills Adam, and Brett kills Bill. Clearly, there is something that links Arthur's firing to Adam's death (but not to Bill's death), and something that links Brett's firing to Bill's death (but not to Adam's death).

The 'something' is a causal chain. There exists a chain of events that links Arthur and his gun to Adam, and another chain of events linking Brett and his gun to Bill. The 2 chains of events follow trajectories in time and space. It is the existence of such a chain that allows us to say that Arthur killed Adam, and it is the corresponding non-existence of such a chain that rules out our saying that Arthur killed Bill. Kim refers to such chains as 'pairing relationships'. In Humean terms, pairing relationships correspond to continuous contiguity.

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4. Ruling Out Supernatural Causation

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So what about putative supernatural causation? For example: the causation of physical events by Cartesian supernatural souls.

To return to our thought experiment:

What if Arthur and Brett were non-spatial entities? Or alternatively: what if we (arbitrarily) ruled out spatial reference in our explanation?

Then there would be no way of connecting Arthur to Adam (but not to Bill), and no way of connecting Brett to Bill (but not to Adam). Remember: the guns are identical, and are fired simultaneously, so temporal coincidence is of no help here.

So how can we say that Soul A causes Event E, rather than Soul B causing event E? We can't. In the absence of a pairing relationship, theres simply no way of connecting the cause to the effect. And pairing relationships require spatiality.

Thus: it makes no sense to attribute causal powers to non-spatial entities. And since the supernatural souls of Cartesianism are non-spatial, they cannot be accorded causal powers. Supernatural causation is incoherent.

Of course, the Dualist may say something like this: 'Souls have an affinity with certain bodies'. Its this alleged affinity that connects the supernatural cause to its natural effect. But this won't wash. For what could the so-called 'affinity' be if not a causal relationship of some kind? As Kim says, the 'affinity' counter-argument is a labellling of the problem, but not a solution.

Note that this argument indicates that any putative causal relationship involving non-spatial supernatural entities is incoherent. It applies to natural -> supernatural, supernatural -> natural and even supernatural -> supernatural.

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5. Putting the Supernatural Into Space: A Futile Move

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An obvious move for the dualist might be to say that supernatural stuff does exist in space after all. This would make the soul more like its popular image of somehow existing 'inside' the body, but it doesn't really work. Heres why:

Say the soul has a spatial location. If thats so, then it certainly isn't a mathematical point- the enormous complexity of the mind rules out that possibility. So the soul must also have volume, and also (as a complex entity) structure. Furthermore, it must be impossible for 2 souls to occupy the same space. If that isn't the case, then we're back with the impossibility of attributing causal powers to one particular soul rather than another one. Thus something like the principle of the 'impenetrability of matter' must apply to souls (pp. 88-90).

So we have 'supernatural' stuff that: occupies space; has structure; is covered by an impenetrability rule; is causally connected to other 'supernatural' and natural stuff. Its difficult to see how this stuff is in any meaningful sense 'supernatural'- it exists in the material world, and behaves significantly like natural matter. And theres no principled reason why it shouldn't come under the purview of natural science.

Attempting to save Dualism by spatializing the supernatural only succeeds in destroying it. We are left with an odd form of materialist monism.

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6. Implications for Theism

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I will now be going beyond the scope of Kim's original version, and consider the implications of the argument above for theism.

One possibility is that god, like a cartesian soul, does not exist in space. This would make god causally impotent. However, it isn't the usual christian view. From the Catholic Encyclopaedia:

That God is not subject to spatial limitations follows from His infinite simplicity; and that He is truly present in every place or thing — that He is omnipresent or ubiquitous — follows from the fact that He is the cause and ground of all reality...God is really present everywhere in creation not merely per virtuten et operationem, but per essentiam. In other words God Himself, or the Divine nature, is in immediate contact with, or immanent in, every creature — conserving it in being and enabling it to act.

This is standard stuff. Omnipresence is one of the many putative attributes of the christian god. From Rev D.H. Kuiper of the Reformed Witness Committee:

We need space just as we need time. God does not need space, is not affected by space, and does not think in terms of space. God's omnipresence is that virtue according to which He is present in every point in space with the whole of His Being. Now we are apt to think that God fills the entire universe which He created, and then goes a little bit further than the edges of the universe. But God cannot be contained by space. You cannot measure the distance between God and some point in the world.

What to make of this? God exists in space, but in all of space- he doesn't have anything like a location. So picking out a causal chain or pairing relationship between god and anything else appears to be impossible- theres nowhere specific that the chain could be said to start from.

Another approach might be to say that since god is everywhere, absolutely any causal chain must begin and end with god. This isn't helpful either. God becomes a co-cause of absolutely everything, including the things that christians wish to attribute to the action of human libertarian free will. The problem of evil looms very large indeed.

What doesn't seem possible is that god could be causally responsible for only some things. If god is omnipresent then you can argue that he can't cause anything, or you can argue that he must be at least a co-cause of everything. In the first case he cannot be omnipotent. In the second he cannot be omni-benevolent. Either way, the christian 'god' construct is incoherent.

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