Mind-Body Dualism - Is the Mind Purely a Function of the Brain?
Dr. Steven Novella has laid down the gauntlet. In a recent post, Dr. Novella, a materialist who asserts that "every single prediction" of materialism has been proven by neuroscience, listed the predictions of his theory that the mind is caused entirely by the brain:
If the mind is completely a product of the material function of the brain then: 1) There will be no mental phenomena without brain function. 2) As brain function is altered, the mind will be altered. 3) If the brain is damaged, then mental function will be damaged. 4) Brain development will correlate with mental development. 5) We will be able to correlate brain activity with mental activity – no matter how we choose to look at it. [numbers added]
He goes on:
What Egnor has not done is counter my claim that all predictions made by the materialist hypothesis have been validated. If he wishes to persist in his claims, then I openly challenge Egnor to name one prediction of strict materialism that has been falsified. To be clear, that means one positive prediction for materialism where the evidence falsifies strict materialism. This does not mean evidence we do not currently have, but evidence against materialism or for dualism. I maintain that such evidence does not exist – not one bit. Prove me wrong, Egnor.
Predictions of Dualism
I do wish to persist in my claims. Now of course dualism also has predictions, which, organized in accordance with Dr. Novella’s predictions, are:
If dualism is true and the mind is partly the product of the material function of the brain and partly the product of something else, then:
- There will be some mental phenomena without brain function
- As brain function is altered, the mind will not necessarily be altered
- If the brain is damaged, then mental function will not necessarily be damaged
- Brain development will not necessarily correlate with mental development.
- We will not always be able to correlate brain activity with mental activity – no matter how we choose to look at it
Note the similarities and the differences in the predictions. Dualism and materialism both predict that mental function will often correlate with brain function. Strict materialism takes it further: mental function will always correlate with brain function, because mental function is brain function. Dualism predicts that mental function and brain function won’t always correlate, because mental function isn’t the same thing as brain function.
Materialism vs. dualism
When we examine experimental evidence, we must examine situations in which the predictions of dualism and strict materialism diverge. It will do no good to examine evidence in which dualism and strict materialism make the same prediction. For example, both dualism and strict materialism predict that severe brain injury will often severely impair mental function. The finding that many brain injured patients have mental impairment favors neither dualism nor strict materialism; both predict it.
Yet dualism and materialism differ in that dualism predicts that there will be some (perhaps very few) situations in which brain injury and mental impairment will not correlate well, whereas strict materialism predicts that brain injury and mental impairment must always correlate, because mind states are brain states.
Now, of course, there are subtleties. If strict materialism is true, it may not always be easy to discern what brain state gives rise to a particular mind state. If we find a disparity between a mind state and a brain state, it may be because we are looking at the wrong brain state. Contra Dr. Novella, these issues are not always clear, but reasonable inferences based on evidence can often be drawn.
Evidence for dualism
Comparing the straightforward predictions of strict materialism and dualism, let’s begin to examine the evidence. I’ll choose one of Dr. Novella’s own examples, which he used in his post: a remarkable study from Cambridge of a woman in a persistent vegetative state.
Dr. Novella wrote:
To give one example [of the irrefutable evidence for strict materialism], two years ago Adrian Owen published an article in Science1 in which he used fMRI to examine the brain function of a young woman in an apparent vegetative state. During the study she was asked to either imagine herself playing tennis or to imagine herself walking through her house. These two distinct thoughts created distinct patterns of activation on the fMRI - indicating that she was actually capable of thought. But the relevance to this discussion is that different thoughts correlate to different functional states of the material brain. In fact this is what all fMRI research shows.
I agree with Dr. Novella. The study by Owen and his colleagues at Cambridge has a great deal of relevance to our discussion. Let’s take a closer look at the Cambridge study.
In the September 2006 issue of Science, Dr. Owen and his colleagues published a study entitled "Detecting Awareness in the Vegetative State." Owen and his colleagues studied the responses of a woman who was in a persistent vegetative state, which was the consequence of severe diffuse brain damage that she had suffered in an automobile accident the year before.
The patient had no evidence of any mental function. Based on a battery of standard tests, including MRI scans, electroencephalograms (EEG’s — brain wave tests), and careful bedside examinations by neurologists and neurosurgeons, she was diagnosed as being in a persistent vegetative state. Persistent vegetative state means that she had no mental state — no consciousness. She was, in a sense, a shell, a human body without a mind. That’s what "vegetative" means.
Owen and his colleagues did a fascinating series of tests. First, they asked a group of normal volunteers to have a kind of research MRI scan of their brain, called a functional MRI (fMRI). fMRI doesn’t measure the actual activity of the neurons in the brain, but it measures the blood flow and brain metabolism in specific regions of the brain. It has been found to correlate to some extent with mental activity. Thinking about things can make the metabolism in certain parts of the brain increase, and fMRI can detect this. The observation that brain activity can locally increase brain blood flow and metabolism was originally made a century ago, in animals in the lab, so it’s not new. What is new is that we can now measure it in living people non-invasively, using fMRI.
The Cambridge researchers asked the volunteers to think of things, like playing tennis or walking across the room, and they recorded their fMRI brain responses. They also presented the volunteers with nonsense words, to distinguish understanding in the brain from the mere reflex to sounds. The response to understanding was different from the response to sound. The fMRI test seemed to test understanding, not just reflexes.
They did the same tests to the woman who was in a persistent vegetative state. They asked her to imagine playing tennis or imagine walking across the room, and they did the sham test with random words as well.
When they examined her fMRI responses, they found that her fMRI patterns were identical to those of the normal awake volunteers. By fMRI criteria, she understood. In fact, by fMRI criteria, she was as conscious as the normal volunteers. Her brain was massively damaged, to the extent that she had been diagnosed as having no mind at all. Yet the blood flow and metabolism patterns in her brain were those of a normal person. And just like normal people, she showed different fMRI responses to nonsense words. So she not only heard what was said to her, but she understood, and complied with the researchers’ requests to think about specific activities like playing tennis and walking across a room.
Implications of Owen's study
Owen’s study generated enormous interest among researchers, physicians and the public, not only for its implications for diagnosis of persistent vegetative state (e.g. the implications for the Terri Schiavo case), but because of what it suggests about deeper questions about the relationship between the mind and the brain. Many other studies of fMRI in patients in persistent vegetative state are underway, and several studies recently completed with other patients tend to support Owen’s findings.
From a scientific standpoint, Owen’s study is important for three reasons. The first is obvious; the last two are more subtle, but very important:
- Owen’s study demonstrates that normal consciousness might be present in some patients who have met the clinical criteria for persistent vegetative state, which is defined as a state lacking consciousness.
- It demonstrates that methods of assessing brain state and function (e.g., MRI, EEG, clinical examination, fMRI) can differ profoundly in their assessment of consciousness.
- It demonstrates that an indirect assessment of brain function (fMRI, which measures regional blood flow and brain metabolism), may reveal evidence for consciousness when more direct methods (clinical examination, EEG) fail to detect consciousness.
Note that each of the three conclusions that can be inferred from Owen’s study is evidence for the lack of correlation between various methods of assessing consciousness based on assessment of material properties of the brain. The inconsistency between the fMRI and the other standard methods of assessment is striking. If the mind is the brain, why would different measures of brain function yield contradictory measures of mind function? If materialism is true, correlation between brain function and mind function should converge, not diverge.
Now, let’s consider Owen’s findings in light of Dr. Novella’s specific predictions about mind/brain correlation. The study actually addresses three of Dr. Novella’s predictions:
- As brain function is altered, the mind will be altered.
- If the brain is damaged, then mental function will be damaged.
- We will be able to correlate brain activity with mental activity – no matter how we choose to look at it.
- As brain function is altered, the mind will not necessarily be altered
- If the brain is damaged, then mental function will not necessarily be damaged
- We will not always be able to correlate brain activity with mental activity – no matter how we choose to look at it.
Owen's evidence correlates much more closely with the predictions of dualism than it does with the predictions of materialism. Consider each prediction:
Strict materialism: As brain function is altered, the mind will be altered
Dualism: As brain function is altered, the mind will not necessarily be altered
Dr. Owen’s evidence is in accordance with the dualist prediction. The most parsimonious conclusion was that she was conscious, despite a diagnosis, based on traditional neurological examination, EEG, and neuroimaging, of persistent vegetative state, which is defined as the absence of consciousness. This panoply of neurological tests predicted different — and incompatible — things. Standard brain tests indicated that she had no mind. fMRI testing indicated that her mind was indistinguishable from that of a normal person. Recall that Dr. Novella insists that "every single prediction" of materialism has been verified. That's not possible with tests that yield contradictory results.
Strict materialism: If the brain is damaged, then mental function will be damaged.
Dualism: If the brain is damaged, then mental function will not necessarily be damaged
Again, Dr. Owen’s evidence is more consistent with dualism than it is with materialism. The patient’s brain was profoundly damaged, but her fMRI correlated with normal conscious thought.
Strict materialism: We will be able to correlate brain activity with mental activity – no matter how we choose to look at it.
Dualism: We will not always be able to correlate brain activity with mental activity – no matter how we choose to look at it.
Dr. Novella’s claim is directly falsified by Owen’s work, because different studies of brain activity gave opposite conclusions about the patient’s mental activity. Dr. Owen’s findings are clearly more consistent with the dualist prediction than with the strict materialist prediction. The central finding of the Cambridge researchers is that correlation between brain activity and mental activity can be quite nebulous, and the findings can even be completely contradictory. fMRI suggested the woman was fully conscious; all other tests suggested that she was in persistent vegetative state, without any consciousness at all.
Strict materialism predicts that mental function will always correlate with brain function, because mental function is the same thing as brain function. Dualism predicts that mental function and brain function won’t always correlate, because mental function isn’t the same thing as brain function. The Cambridge findings are more consistent with the dualist prediction than with the strict materialist prediction. That is, in a sense, why the paper received so much attention; it suggested that mental function may not be linked to brain function in a strict cause-and-effect relationship.
So is it reasonable to conclude that Owen’s findings prove dualism? Of course not. Science doesn’t work that way. Scientific theories prevail by preponderance of evidence and by carefully considered inferences, not by "proof" or by validation of "every single prediction." Hyperbole is the currency of hucksters, not scientists. But the growing body of scientific evidence, which is consistent with my experience as a neurosurgeon for 23 years, suggests that the strict materialist theory of the mind is simplistic and probably wrong. There’s scientific evidence that justifies the inference that there is more to the mind than the brain.
Dr. Novella again:
The materialist hypothesis - that the brain causes consciousness - has made a number of predictions, and every single prediction has been validated. Every single question that can be answered scientifically - with observation and evidence - that takes the form: “If the brain causes the mind the...” has been resolved in favor of that hypothesis.... [w]hat Egnor has not done is counter my claim that all predictions made by the materialist hypothesis have been validated. If he wishes to persist in his claims, then I openly challenge Egnor to name one prediction of strict materialism that has been falsified. To be clear, that means one positive prediction for materialism where the evidence falsifies strict materialism. This does not mean evidence we do not currently have, but evidence against materialism or for dualism. I maintain that such evidence does not exist – not one bit...
...Prove me wrong, Egnor…
Originally posted as Proving Dr. Novella Wrong: Enjoying Tennis in a Persistent Vegetative State at Evolution News & Views, a service of the Discovery Institute. Reprinted with permission.
- The Spiritual Brain: A Neuroscientist's Case for the Existence of the Soul
- Man, Created in the Image of God: How Man is Unique Among All Other Creatures on Earth
Who Was Adam?: A Creation Model Approach to the Origin of Man. Are humans just advanced apes or have they been specially created in the image of God? Publications by scientists almost never ask the question, whereas publications by theists seldom examine the scientific data that relates to the question. However, two scientists raised in non-Christian homes, Fuz Rana (Ph.D. in chemistry) and Hugh Ross (Ph.D. in astronomy), have written a new book (Who Was Adam?: A Creation Model Approach to the Origin of Man) that examines the question of human origins by comparing biblical and evolutionary models.
Book Review: Why We
Believe What We Believe: Uncovering Our Biological Need for Meaning,
Spirituality, and Truth
Last updated March 3, 2008