Apr 29 2008
Dr. Egnor must be tired of always being wrong – or at least he would be if he had the insight and intellectual honesty to see how persistently wrong he is. Alas, so far he has not demonstrated such insight. I have been engaged in an ongoing blog debate with Dr. Michael Egnor, who writes for the propaganda blog of the Discovery Institute, over the question of whether the scientific evidence supports the strict materialist hypothesis of mind, or the dualist hypothesis – that the mind is something more than the function of the brain.
Egnor has mangled most of his arguments, has misrepresented my opinions, has cruelly assaulted logic (as you can see he has a proper home at the Discovery Institute) – but now he demonstrates that he is incapable of reading a simple sentence and comprehending its meaning.
Two weeks ago I wrote about an fMRI study that looks at the process of decision making in the brain. (Rather than re-summarizing this study, just read this post before proceeding.) At the end I wrote:
Given my recent posts concerning materialism vs dualism (does the brain cause mind), I also want to point out that this research falls squarely in the materialism camp. Causes precede their effects – brain activity precedes conscious awareness and action – the brain causes mind. That much seems pretty clear.
In response to this, Dr. Egnor wrote yesterday:
This research “falls squarely in the materialist camp”? That’s a remarkable assertion. Dr. Novella asserts that this bit of evidence for correlation (rather weak correlation) between unconscious mental processing and brain activity supports materialism.
He then proceeds to argue that the weakness of the correlation is actually support for dualism, not strict materialism. His entire argument is nothing more than a straw man, since I did not offer the correlation in this study as evidence for materialism. My point was that in this study brain activity preceded conscious awareness. It it the temporal sequence – not the accuracy of the correlation – that I was pointing to as evidence in support of materialism.
The reason I bothered to point this out is because one of the primary arguments used by dualists is the notion that brain activity only correlates with mental activity – and since correlation alone does not prove causation, it is possible that the mind causes brain activity, or that some third thing causes both. Logically speaking, this is true. These are always the options to explain a correlation between A and B: A causes B, B causes A, or C causes A and B.
This is, in fact, a common strategy of denialism in general – the denial of legitimate science. Denialists would have us believe, for example, that HIV only correlates with AIDS, and that smoking only correlates with certain types of lung cancer – but that these relationships are not causal. Correlations are very useful evidence in science. And it is important not to assume any particular pattern of causation from a correlation. But good scientists do not do that. It is necessary to look at correlation from multiple perspectives, to ask questions that derive from the various causal hypotheses and then eventually arrive at the most likely causal explanation for the correlation. (All this assumes that the correlation has been established as real and is not a statistical fluke.)
Let’s now apply this to the question of the brain-mind correlation. It is a well established tenet of science and philosophy that causes precede their effects. An effect cannot occur prior to a cause. If someone gets lung cancer before they start smoking, no reasonable person would attempt to blame the cancer on the smoking. Therefore, if brain activity causes the mind then we would expect that brain activity would generally begin prior to the mental effects caused by the brain activity. If, rather, the mind causes the corresponding brain activity then we would expect a mental experience to happen before the brain activity. If some third phenomenon causes both mental activity and the corresponding brain function, then we would expect both to occur simultaneously, although either could precede the other if there were differing lag times for the mind and the brain.
This third possibility, of a third factor causing both mind and brain, is not currently a consideration, as far as I can tell. It would be difficult to experimentally rule out such a third cause, and so the burden would be on anyone advocating this to postulate what this third cause could be, and also how we could experimentally tell if this is the case. Otherwise we can use Occam’s razor to set it aside from serious consideration.
The major question, as Dr. Egnor himself states, is: “Does the unconscious mind cause the brain activity, or does the brain activity cause the unconscious mind?” These two hypotheses make clear predictions regarding the direction of causation. If the mind causes brain activity, then we would expect mental activity to manifest prior to brain activity. If brain activity causes the mind then we would expect brain activity to precede mental activity. In this study brain function clearly occurred prior to the corresponding mental activity (the choice being made).
This is in line with neuroscience research in general. When we look at brain activity and mental activity – it is always the brain activity that comes first. This supports the brain causes mind hypothesis. In light of this, dualists can no longer dismiss the correlation between brain activity and mental activity as mere correlation – we have reason to believe that the brain causes the mind.
I expected that most people would have understood this from that brief paragraph from my prior post. Dr. Egnor, however, did not get it – and so he forced me to spell out in detail the logic behind my statement. He still won’t get it, and he will simply move on to his next misunderstanding or misrepresentation, without ever acknowledging his error. This is the dance that denialists do.
As a side note – saying that the “brain causes the mind” is a bit misleading because I think it is more accurate to say that the mind is brain activity. The reason for the long delay (seconds) in this study is because there was a subconscious phase of decision making that occurred prior to the conscious decision. But the argument of causation still holds because even with more direct neurological function there is always at least a 60-70ms (milisecond) delay from when we can see neurons firing to whatever the mental manifestation we are observing. Brain activity always comes before any mental activity with which it correlates.
Also, to put things into historical perspective – the materialist hypothesis predicts that brain function would correlate with mental function. The dualists initially denied this correlation, claiming that the mind is not physical but spiritual in nature. But now the last hundred years of neuroscience has clearly shown a correlation – so much so that the dualists can no longer deny it. So now the dualists acknowledge the correlation, but argue that correlation is not causation. But increasingly, as with this study, and other lines of evidence, the data show that the brain doesn’t just correlate with mental activity – it causes it. Dualists like Egnor then retreat further into the darkness of the gaps in neuroscience. The correlation is imperfect, they say, without recognizing that this can be explained by the limitations in our current instruments and models of brain function – not the materialist hypothesis. Dualism is a “mind of the gaps” argument – defended by perpetual goal-post moving.
I do want to address further the correlation issue that Egnor raised – even though it was not the point of my original comment. Egnor states that the correlation between brain activity and mental activity is imperfect. In this study we are discussing, for example, the pattern of brain activity predicted the left/right choice of the subject 60% of the time, with 50% being chance. This is a weak correlation. Egnor argues:
If Dr. Novella is asserting that evidence for correlation is evidence for materialism, then the evidence demonstrating a lack of close correlation (which is most of the evidence in neuroscience) between mind and brain states is evidence against materialism.
Notice the subtle misdirection here. He states that I am asserting that “evidence for correlation is evidence for materialism.” Although that was not my assertion in my prior post, I do agree that correlation between brain activity and mental activity is a powerful line of evidence for materialism. But then Egnor states that “lack of close correlation…is evidence against materialism.” Notice that he inserted the word “close” in his statement. This changes the nature of his argument altogether – but Egnor does so subtly, without ever drawing attention to it specifically. In fact I have already dealt with this criticism from Egnor, who has not responded to my existing criticism.
To clarify – I never stated that the correlation between brain activity and mental activity, as currently measured by our technology, is perfect. Egnor, however, is pretending that this is my position – which makes his argument just another straw man logical fallacy. What Egnor is saying is that because the correlation is not close (we can quibble about this, since “close” is a vague term, but functionally what he means is that the correlation is not exact) that contradicts the materialist hypothesis and therefore supports the dualist hypothesis.
But as I have already pointed out, and Egnor ignored, the lack of exact correlation is more simply explained by two things: the poor resolution of our instruments, and the complexity of the brain. We are not seeing actual brain activity at the neuronal or even neural network resolution. fMRI looks at brain blood flow and metabolism, and from this we infer brain activity. It’s an excellent tool – but it is tricky to use properly and is much lower resolution than actual brain activity.
Also – as I pointed out in my post, and Egnor quoted, brain activity is complex. In any decision like the ones being studied here, there is a complex interplay between subconscious processing, intention, attention, and conscious awareness. Multiple parts of the brain are playing their own role and interacting to produce a net result. And, we cannot know what people are actually thinking – we can only infer what they are doing because we give them specific tasks to perform.
Further – there are two types of correlation to consider in this study, and Egnor is choosing the one that he feels makes his point without ever acknowledging that he is doing so. One correlation is the correlation between brain activity and the decision-making process. This correlation in the study is very strong. The other correlation is between the particular pattern of brain activity and the specific choice that is made – this correlation is weak in the study: only 60%.
For the purpose of the materialist vs dualist hypotheses, the former correlation is much more important. Brain activity, in the same general parts of the brain, reliably precede the conscious decision-making process. This is the type of correlation that must occur if the materialist hypothesis is correct – brain activity must always occur with (and begin before) mental activity. The correlation Egnor has chosen to focus on – predicting the actual decision being made – has more to do with the limitations of fMRI and our models of how the brain works. This is another example of what I have written about before – that denialists confuse questions at different levels of understanding. The evidence strongly supports the conclusion that the brain causes mind – this conclusion is not called into question because of our limited ability to describe exactly how the brain causes mind, or (even more detailed) how specific decisions are made.
Finally, Egnor (like his intelligent design proponent colleagues) persists in turning reality onto its head by insisting that I am the ideologue. He opens his blog entry by referring to me as “the dogmatic materialist neurologist at Yale” and then concludes::
The Nature Neuroscience article provides no meaningful evidence either for or against dualism or materialism, but Dr. Novella’s citation of it to support his materialist ideology tells us a great deal about how Dr. Novella approaches scientific evidence. He’s a materialist ideologue. He views the scientific evidence through materialist glasses, and sees evidence for materialism…everywhere.
The opposite is true. The article does provide meaningful evidence for the materialist hypothesis, by supporting a temporal sequence that is consistent with the notion that brain causes mind, rather than mind causing brain. Egnor’s rebuttal is a straw man, and a false one at that. Further, the exchange reveals that Egnor does not understand scientific reasoning or basic logic, or chooses to ignore them in favor of his dualist ideology.
But like those other denialists – his intelligent design cronies at the DI – since Egnor cannot win his argument based upon logic or evidence he is taking the “dogma gambit.” He is trying to portray those who support the strong scientific consensus based upon a fair assessment of the evidence as being dogmatic ideologues. Wishing does not make it so.
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