Feb 11 2008

Intelligent Design of the Brain

Dr. Michael Egnor, a neurosurgeon who has decided to take on a second career as an intelligent design proponent, has been embarrassing himself over at the Discovery Institute propaganda blog. He has dropped some real gems, like the claim that if evolution were true then brain cancer should evolve a better brain. Recently he has been taking me on over the question of the materialist vs dualist concept of the mind. On Friday he posted his latest reply, nicely illustrating that he can apply the same logical fallacies favored by the intelligent design proponents to the question of dualism.

In response to this statement that I wrote in my previous blog entry on this topic:

The materialist hypothesis— that the brain causes consciousness — has made a number of predictions, and every single prediction has been validated.

Dr. Egnor replies:

A bit of advice: whenever a scientist says of his own theory that “every single prediction has been validated’, you’re being had. No scientific theory has had ‘every single prediction’ validated. All theories accord with evidence in some ways, and are inconsistent in others. Successful scientific theories prevail on the preponderance of the evidence, not validation of “every single prediction”. Real science lacks the precision of ideology.

This is one of those statements that seems reasonable on the surface, but with a bit of thought, and a modicum of scientific knowledge, we can see that it is just deceptive rhetoric. Science progresses chiefly by formulating hypotheses to explain observed phenomena, and then testing those hypotheses with observation and experimentation. It is true that often the data does not point entirely in one direction – depending upon the type of data that is being collected and the complexity of the question.

But this actually misses the point I was making, which is this: in order for a theory to survive it must be validated by every observation or experiment that has the potential to falsify it. It is a trivial application of logic to say that in order for a theory to be considered true it cannot have been falsified or found to be untrue. Theories that are falsified are either modified or discarded. A “preponderance of evidence” cannot rescue a theory that has been disproven even by a single piece of incompatible evidence.

It is also historically true that many scientific theories have been validated “by every single” piece of evidence that bears upon the basic question of whether or not the theory is true. Let’s take special relativity, for example. Einstein proposed this theory in 1905, and his claim that space and time are relative makes a number of specific predictions. In the last century every single prediction made by special relativity has been validated. There is not one observation that falsifies special relativity. (That would be big news if there were.) I guess Egnor thinks that all physicists are not “real” scientists and are just conning the public.

The same is true of evolutionary theory. The evolution deniers (creationists/intelligent design proponents) often point to those details that evolutionary scientists have not yet fleshed out in order to claim that the evidence for evolution is lacking. In addition to this being an argument from ignorance, they also are missing the point. We need to separate the lines of evidence for the question of did life on earth evolve from the questions of how it evolved or what particular evolutionary paths life took. If we focus just on the question of did life evolve we see that this theory makes a number of predictions. So far, every prediction that flows from the evolutionary hypothesis has been validated. There is no evidence that falsifies evolution, or is incompatible with evolution.

Here are some examples. The fossil record exists in an evolutionary pattern. There is not a single fossil that falsifies evolution – no horses in the Cambrian strata. Genetic evidence is also found to exist in an exquisitely evolutionary pattern – one of branching relationships among groups that closely follows the pattern we would infer from morphology.

Intelligent design proponents argue, falsely, that if evolution were true than evolutionary scientists should be able to explain exactly how every structure, biochemical pathway, and organism evolved. They then conclude that the inability of scientists to explain exactly how everything evolved falsifies evolution. What they are doing is just taking the “god of the gaps” logical fallacy and trying to reformulate it to make it sound like a scientific prediction. This exposes several problems for the ID proponents and the logical fallacies they employ to cover them over.

First, as I said, they cannot point to any positive prediction made by evolution that was falsified. So they invent one by claiming that evolutionary theory is falsified if it cannot currently explain every tiny detail of how evolution occurred. They can then link this fallacy to the moving goalpost logical fallacy – as evolutionary scientists make new discoveries, just keep moving the goalpost back and proclaiming that evolution is falsified.

The second problem is that ID does not make any positive predictions for itself. It therefore cannot be specifically falsified and that is why it is not a scientific theory. But ID proponents are adept at fixing these nagging logical problems by simply lying. So they pretend that ID can be falsified – all you have to do is prove every last detail of evolution. Saying that proving evolution falsifies ID does not make ID a scientific theory – it is simply committing the false dichotomy logical fallacy. This is the claim that either evolution is true or ID is true (the false dichotomy) and therefore until you prove evolution 100% ID wins by default.

This also relates to the third major problem with the ID line of argument – it is dependent upon what has not been discovered. There is no evidence against evolution, so ID proponents point to evidence that does not yet exist and treat it as if it is positive evidence against evolution. On top of that they get the context of the evidence wrong – they point to the lack of evidence for how evolution occurred, not if it occurred.

As we will see, Dr. Egnor applies the exact same intellectual strategy to the question of strict materialism vs dualism. He writes:

“We have a vast knowledge of neuroscience. Yet what is the scientific evidence supporting this most fundamental prediction of materialism— that every thought is reducible at the molecular level to a discrete and unique brain state? There isn’t a shred of evidence that any discrete mental state— any specific thought— can be reduced at the molecular level to a unique material brain state. Not a shred.”

Egnor’s strategy here is to claim that neuroscientists have not yet proven that every specific thought reduces to a specific molecular brain state, and that materialism predicts that we should. This is as absurd as arguing the evolution predicts we should be able to explain every single biochemical pathway, and that until we do evolution has problems. Egnor’s statement is actually false, but even if it weren’t it makes no logical sense, and does not address my claim that all predictions made by materialism has been validated.

The materialist theory of mind does not predict that we will have the technology to examine brain function at the most reducible molecular level. What it predicts is that once we do what we find will be compatible with materialism. Egnor can present no evidence that thought does not reduce to specific material states of the brain. Any current lack of evidence is not a reflection of problems with the materialist theory but just limitations of our current technology.

But Egnor’s claim that there is “not a shred” of evidence that mental states correlate with specific material states in the brain is demonstrably false. We can now look at the brain with functional MRI scanning – we can create an image of which neural networks within the brain become active with a specific thought or mental task. When we do this we find that there are specific material brain states that correlate with specific thoughts. To use Egnor’s example, if subjects were made to think “the White House is in Washington, D.C.” that would produce a different pattern of activity than thinking, for example, “ID proponents are a bunch of baboons.”

To give one example, two years ago Adrian Owen published an article in Science 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 was all fMRI research shows.

Therefore, within our current technology, to the limits of resolution that we can now image brain function, the materialist theory is validated – specific thoughts do correlate with specific patterns of brain activity. Egnor is quite simply wrong.

But you can see the “moving goalpost” strategy he is implying as well. He is acknowledging, to some degree, that current evidence supports materialism. He writes:

“Both dualists and materialists recognize that matter influences the mind. Wine affects dualists just as it does materialists. The difference in viewpoint is this: dualists propose that the mind is in part caused by matter, and in part caused by something else. Mental causation is dual. Materialists believe that the mind is entirely caused by matter. There is nothing else.”

What evidence does Egnor present that dualism is necessary? None. What evidence does he present of an observation, phenomenon, or experiment that cannot be explained by materialism, and therefore requires that there be “something else?” None. Materialism explains all currently available evidence. Egnor simply pulls the ID strategy of pointing beyond current technology and evidence to say that materialism has not produced this evidence. He then moves the goalpost beyond current evidence, and will keep doing so forever, because our scientific knowledge will never be complete.

Let’s get back to my core claim – that all predictions made by mental materialism that can be falsified scientifically, and for which we have evidence, have been validated. There are no predictions that have been falsified. If Egnor disagrees with this he needs to give a counter example. He can’t do it, which is why he made up his intelligent design of the brain deception.

I listed the specific predictions in my previous post on this topic. Egnor was not able to counter any of the examples I gave. Here they are again:
If the mind is completely a product of the material function of the brain then:
– There will be no mental phenomena without brain function.
– As brain function is altered, the mind will be altered.
– If the brain is damaged, then mental function will be damaged.
– Brain development will correlate with mental development.
– We will be able to correlate brain activity with mental activity – no matter how we choose to look at it.

All of these predictions have been resolved in favor of materialism. “Every single one!” Dualism makes predictions too – that some mental function will be documented to exist separate from brain function. The evidence for this? None. Egnor claims that dualism predicts that neuroscience will fail to find specific molecular states for thoughts, and then declares victory on this score. This is not a positive prediction, however, just a negative prediction. This is exactly like saying that ID predicts evolutionary theory will fail to explain every last biochemical pathway. A negative prediction for some other theory is not the same as a positive prediction for your pet theory (again, the false dichotomy logical fallacy).

Egnor’s intelligent design gambit for dualism fails. Materialism is not falsified because he have not yet developed the technology to image brain function at the molecular level. The ways in which we can currently image brain function, fMRI, shows that specific thoughts do correlate with discrete material brain states. So Egnor is also ignorant of the current facts of neuroscience (and he’s a neurosurgeon).

Not content with the degree of nonsense Egnor has so far spewed forth, he decided to add a few bonus absurdities. He wrote:

“The materialistic hypothesis creates even more problems. Imagine that Dr. Novella and I are both simultaneously thinking “the White House is in Washington, D.C.”. Do we both simultaneously have exactly the same brain state, defined in terms as acetylcholine, dendrites, etc.?”

This is a complete non-sequitur. The materialist model of neuroscience does not predict that the same thought will correlate with the exact same molecular state in different people. This is such utter nonsense it is almost surprising – except that Egnor has already demonstrated his capacity for such nonsense. Different brains certainly have much in common – the same basic anatomical structure and biochemical function. But there is good reason to believe that there are also significant differences in detail. The name “Washington” is probably not coded in my brain’s language center exactly the same as anyone else’s brain. Plus we know that human memory is contextual and works largely through pattern recognition. The word “Washington” conjures up in my brain a different set of memories, images, ideas, and thoughts than any other person. Although human brains generally follow the same rules, the specific manifestation for any individual is likely to vary considerably.

Egnor next brings up the notion that consciousness is an “emergent property of the brain.” However, in this context this is a straw man. Emergent property does not need to be invoked to explain the fact that we do not yet have a specific molecular model for specific thoughts. This is purely a technological limitation, not a conceptual failing of materialism. To be clear (in case he tries to bring this up) I have invoked the “emergent property” argument before, but that was to explain how the subjective experience of consciousness emerges from brain function – not as an excuse for the alleged absence of discrete molecular states.

The sloppy thinking on the part of Dr. Egnor is profound, but it can be understood as an application of intelligent design sloppy thinking to the question of materialism and dualism. 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.

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