Bram Vaassen (Umeå University), "Mental Causation for Standard Dualists"

Australasian Journal of Philosophy, 2024

Mind-Body Interaction Is So Cheap Even Dualists Can Afford It

By Bram Vaassen

Dualism about the mind and the body sounds suspiciously esoteric. It holds that our mental lives are somehow decoupled from all matter, including our brains. A claim fine for mystics and those religiously inclined, but the scientifically minded will have none of it.

One reason to have none of it is that all the mind stuff can be explained away by brain stuff. The more we learn about the brain, the more we learn about the mind. So much so that we should not bother with having a mind over and above a brain.

Another reason is that endorsing a strict separation between the mind and the brain makes a muddle of mind-body interaction. If the two are so separate, then how come our minds often determine what our bodies do (and vice versa). All the interaction seems to happen via the brain. But how could a material brain and an immaterial mind causally interact?

To insist on dualism in the light of these considerations is just to insist that your mind is more special than it actually is. It’s reactionary. It relies on outdated assumptions. And, worst of all, it is not motivated by the available evidence.

So, we have both explanatory reasons and causal reasons to not be dualists. The dualists themselves have pushed back on the explanatory reasons. It turns out, they say, that the brain explains a great deal about the mind, but it still doesn’t explain enough. Its workings may explain how our beliefs react to new information, or how alcohol consumption promotes exhilarated behavior. But they fall short of explaining why any of these processes should be accompanied by consciousness – i.e., why it should feel like anything to revise beliefs or have exhilarating thoughts.

The brain may explain much about the mind, but it does not explain the mind away.

Our case against dualism now rests on the causal reasons. This has long been considered safe and solid ground. Immaterial minds causally interacting with material brains and bodies certainly seems too fantastical to take seriously. But why exactly does it seem that way?

Well, at first glance, causes seem to do their causing by being materially integrated in some way – by having mass and exerting some force or energy. Billiard balls cause other billiard balls to roll by transferring some physical quantity on them (force, acceleration, or whatever the physicists tell us it turns out to be). Immaterial minds possess no such physical quantities to transfer. They are, more or less by definition, not materially integrated in the world. Therefore, they cannot cause events in the material world either.

The problem with this line of reasoning is that the transfer-of-quantity idea of causation turns out be no good. Plenty of causes do not possess physical quantities. The absence of the mother can cause the child to cry, and the lack of proper support caused the bridge to collapse, but neither event seems to have any physical quantity that it transfers onto the effect. Gravity exerts a force on the bridge, as do the facial muscles on the tear ducts of the child. Once all this passing around of physical quantities is done, there is somehow still causal work left for the absence of the mother and the lack of proper support. They do this work without any transfer of physical quantity.

Further, we typically investigate causal relations without paying much attention to transfers-of-quantity. If we want to know whether social distancing causes a decline in infections, or whether parental income levels cause academic success, we rely on statistical analyses to figure out whether bringing about one is a reliable way of bringing about the other. These analyses do not attempt to identify a specific physical quantity transferring from social distancing to infection rates, or from numbers in bank accounts to numbers on report cards. One being a reliable way of controlling the other suffices to attain causal status.

So, while being materially integrated and transferring a physical quantity might certainly be a way of being a cause, it is not the feature that makes something a cause. What makes something a cause is its ability to serve as a point of control for the other event. We can take control over the crying of the child by controlling the presence or absence of the mother, and we can take control over the spread of disease by implementing social distancing rules. For some causes, the ability to be a point of control is supported by transferring a physical quantity, as is the case for the muscles surrounding the tear ducts. For other causes, such as the absence of the mother, this is simply not the case.

This situation provides the dualist with good ammunition. Absences, parental income, and social distancing are all awarded causal status in virtue of being points of control and without requiring a transfer of energy onto the effect. Why should the mind be any different?

The mind clearly serves as a point of control for our behaviour. We exploit this fact when we ask people to hold the door, or when we say mean things just to hurt someone; by affecting mental states, we aim to affect future behaviour. We have known that these practices work since well before we settled on whether the mind is material. And now we know that such a pattern of exploitable control can exist without transfers of energy or material integration, these patterns provide us with no clear evidence that the mind must be material. The mind might very well succeed in playing this ‘point of control’ role without having any physical features.

“This is all very speculative,” we should respond. The mind might very well play this role while immaterial, but surely a closer look at our best theories of causation and the details of dualism will reveal that the mind would do no such thing in a dualist metaphysics. However, a closer look redeems the dualist. My paper, “Mental Causation for Standard Dualists”, takes Chalmers’ naturalistic dualism and feeds it into an interventionist account of causation. What comes out is a picture on which energy and forces are passed around between physical stuff alone, but some causal work is still done by the immaterial minds floating about. They still serve as control points for our behaviour.

We might recoil. We might insist that this just goes to show that real causation is the passing around of energy and physical quantities after all. But that is not what our best theories of causation say. Instead, they say that to be a point of control suffices for being cause, no questions asked. These theories are informed by several philosophical puzzles about causation and get extra credibility by capturing causal modelling in sciences and everyday life.

To insist on some extra causal oomph in the light of these considerations, is just to insist that causation is more special than it actually is. It’s reactionary. It relies on outdated assumptions. And, I claim, it is not motivated by the available evidence.