In the previous post in this thread, we were considering the causal linkage between my observation of a falling flowerpot and my stepping out of the way, and how a dualist account of such a chain of events might differ from a materialist one. Although the immaterial Mind of the dualist is considered to be not of the physical world, and therefore outside the purview of the natural sciences, that is not necessarily the case, as we shall see.
Picking up where we left off, we examine the sequence of events that begins with my visual detection of the plummeting pot, and ends with my sidewise step, and compare the physicalist and dualist models of what is taking place.
To the physicalist, the mind and body are entirely contained within the one and only natural world, are subject to all its customary regularities, and we ought in principle be able to follow the causal sequence from beginning to end. While the microdetails of causation are still the subject of vigorous philosophical debate, there is no reason to assume that we need a complete philosophical understanding of causation at the bedrock level to make a description of the causal processes of the brain. We commonly make causal accounts at macroscopic hierarchical levels — a hammer drives a nail, an enzyme catalyzes a reaction — without worrying about such esoterica, and there is no reason to assume that examining brain processes at such a level will be inadequate either.
So, if we may assume some brain-imaging technology that allows us to follow in precise detail the patterns of neural excitation, chemical exchanges, and so forth that occur as we react to our falling flowerpot, the physicalist would expect us to be able to trace an unbroken causal chain of brain activity all the way through, from initial detection to moving out of the way. The dualist, on the other hand, will claim that at some point the signals taken in by the eyes are in some way presented to the immaterial Mind, which in turn, having made its decision, sets in motion the physical events that result in our hopping to the side.
If the dualist model is correct, then, we can divide the causal flow into “upstream” and “downstream” segments. There is no “seeing”, then, in the upstream leg of the journey, or anywhere else in the brain; the subjective experience of vision is not a physical process at all. More importantly, the decision-making — the “free” act of will that is ultimately responsible for the dodging of the flowerpot — is, in the dualist view, an entirely non-physical process as well. At the end of the “upstream” part of the process, then, the visual signal is presented to the Mind, and at the headwaters of the “downstream” flow the Mind sets in motion the motor signals that will get us out of the way.
But what this means is that there should in principle be observable consequences to dualistic mind-body interactions: if we can follow the causal process with sufficient sensitivity, we ought to see a place where the upstream and downstream portions of the causal chain are disconnected — and in particular, if we closely examine the downstream side, we should see an onset of neural activity without any apparent antecedent cause. Should such a violation of “causal closure” be observed, it would be a major result in support of a dualist view.
On the other hand, however, if the physical causal chain were found to be unbroken — if a continuous account could be made of the entire path, from visual stimulus right through to motor-neuron excitation — then the dualist would be in an uncomfortable spot, because any input from the purely mental realm would be superflous. There would be no reason to believe that there is any need for the physical process, which is sufficient on its own to account for the phenomena, to be “overdetermined” by the mental. The Mind could just as well be a feckless observer, its causal powers a mere illusion. This is still consistent with dualism, of course — the conscious Mind might still actually be some sort of nonphysical “substance” that can receive input across the ontological gap in some unspecified way. But this is far from the exalted role that most dualists — especially those, such as C.S. Lewis, who see our minds as splinters of the mind of God — have imagined.
The point then, is that there may in fact turn out to be empirical tests to which the dualist account can be put. Making such a detailed assessment of the causal chain I have described exceeds — far exceeds, I freely admit — our present technical skill, but the progress of technical ingenuity in this field is astounding, and the pace of innovation is accelerating. We might not have to wait so very long.
Another question for the dualist: where do minds come from? We’ll puzzle over that one next.
13 Comments
I have no opinion on the question of whether the dualist model is correct. I would, however, like to express my fervent opinion that life is just a bowl of cherries.
Bing or Hudson?
Life is just a bowl of cherries.
Don’t take it serious; it’s too mysterious.
You work, you save, you worry so,
But you can’t take your dough when you go, go, go.
You’ve got your Kant, your Schopenhauer, your Hegel and your Foucault. But me? I’ll take Chevalier any day.
Bah! Real cherries come from Michigan and are not as sweet as Bing or Hudson. Further, you put them in pies, not bowls. Cherry heaven (should you subscribe to such a notion) is Traverse City Michigan!
– M
Hi Mike, and thanks for weighing in.
I hoped, when I began this series of posts, that it would stimulate an interesting discussion, and I’m gratified to see that it has.
Hey, cherries are a very serious matter to someone from Michigan, bucko! :-)
Couldn’t one consider dodging the flower pot an entirely physical process but still subscribe to a dualist view? I would suppose that depends on where the dualist draws the line between physical and “other”, wouldn’t it? I would think that as science knows more and more about the mind, ‘the line’ might be getting redrawn like Qaddafi’s retreating “line of death”. Is there a standardized place where a card carrying dualist is supposed to draw the line? Have you made assumptions about this for the purpose of your posting?
– M
Hi Mike,
Thanks — you raise an important point, one that I ought to have made clearer.
In the dualist view, what is considered to be on the nonphysical side of the line is whatever is “mental” in nature. This includes anything and everything that takes place in consciousness: perception, qualia, thinking, decision-making, intitiation of volitional actions, and so forth. So to the dualist the seeing of the flowerpot, the decision to move, and the instructions to the body to do so are all taking place in the immaterial Mind. This is in contrast, for example, to the knee reflex, say, or digestion.
What this means is that the answer to the question “Couldn’t one consider dodging the flower pot an entirely physical process but still subscribe to a dualist view?” would have to be no.
Oh!
But wouldn’t that make dualism, in the form you describe, just plain wrong?
– M
Malcolm – I’m sure you could find dualists who would contest your account of where they mark the boundary between the mental and the physical. Dualism is no more monolithic than physicalism.
Hi Mike,
No, as described it is a defensible position, but with difficulties; these posts are an attempt to outline what they are. Of course, my own intuition is that the view described is indeed wrong, but it is not demonstrably wrong — not yet, at least.
Hi Bob,
I do realize that there are various versions of dualism, but this is the typical, “mainstream” version — the “standard model”, if you will — and is the one I had seen presented most often over at Bill V.’s place. But if you wouldn’t mind adding a brief taxonomy of the various alternative dualist positions, and where they’d draw that line, I’m sure it would be helpful in this discussion, and would be welcomed by all.
Malcolm – I’ll beg off the task of constructing a taxonomy of dualisms. I suspect any taxonomy of metaphysical positions would run into problems with “intermediate forms” that would be eerily familiar to students of biological classification.
Fair enough, Bob; I didn’t mean to sound as if I was assigning you homework! You will agree, I hope, that the view of dualism that I am addressing here is fairly representative of the majority position.
That business of intermediate biological forms is an interesting one too, and I actually have a post or two on that topic in the pipeline.