Last week I wrote about dualism – the philosophical position that the mind is somehow more than or separate from the biological activity of the brain. I argued that dualists commit the same error in thinking as creationists when they doubt the causal relationship between brain an mind because we cannot fully explain how the brain causes mind, not recognizing that this is a separate question from does the brain cause the mind. In the same way creationists confuse scientific knowledge concerning how evolution works with the evidence for the fact of evolution. We can know that life evolved without knowing all the details of how, just as we can know that the mind is a manifestation of brain function without knowing all the details of how brain function creates the experience of mind.

In response to this post The Agnostic Blogger wrote this response. In it he writes:

Simply put, he does not understand the dualist’s position. The dualist usually begins with an assumption- the mind exists. Now, this mind displays properties that are unlike physical entities- rationality, volition, awareness. Furthermore, science has not found a neural correlate for consciousness, and it is very possible that they never will. And it is the dualists that are being unskeptical?

It is true that I have never separated out the various forms of philosophical dualism. I am not a philosopher and when I discuss philosophy it is only to the extent that it intersects science, as the question of dualism certainly does. Further, I am interested in how critics of science use philosophy, which often reveals how philosophy has trickled down to the popular culture. Interestingly, while taking me to task for not distinguishing various types of dualism the Agnostic Blogger carelessly uses the phrase “the dualist’s position” – let us, rather, agree that there is a spectrum of dualist positions.

While considering this spectrum of dualism it occurred to me that there is yet another analogy that can be made between dualism and creationism, another denialist tactic they share, which I will get to below.

This is a gross oversimplification from a non-philosopher, but here are the basic types of philosophical dualism (taken from Wikipedia):

(1) Substance dualism asserts that mind and matter are fundamentally distinct kinds of substances.
(2) Property dualism suggests that the ontological distinction lies in the differences between properties of mind and matter (as in emergentism).
(3) Predicate dualism claims the irreducibility of mental predicates to physical predicates.

Substance dualism is the easiest to deal with and, for that reason, has largely been abandoned by serious philosophers. However, it is still in use by the enemies of science. I wrote previously about ID proponent and neurosurgeron, Michael Egnor, who claims that the substance of mind must be different from the substance of brain, even though it is clearly “influenced” by it. Although he does mix in some properties dualism arguments, by saying that the mind has different properties than the physical brain and that is why the latter cannot explain the former.

Property dualism also seems to be the favorite position of many in the spiritualism camp. There are also those, like B. Alan Wallace (who I interviewed on The Skeptics Guide podcast) who claims that the brain creates the mind but that the mind, once created, is a separate thing from the brain itself. There are also those who claim that the brain is some kind of antenna, that it is transmitting or channeling the mind to the physical body.

As I stated in my previous post, the evidence from neuroscience is now overwhelming that the mind is what the brain does. Cruder forms of dualism must deny this body of evidence, and for this reason no serious thinker still maintains that the brain is not at least involved with the mind. But even the more sophisticated forms of dualism must deny the scientific implications of modern neuroscience to some degree, or perform some logical fancy footwork to evade the conclusions of neuroscience.

I pointed out in my previous entry one such “dodge” – confusing the question of how for the question of if. This is also a form of the moving goalpost fallacy: always requiring more evidence from neuroscience than is currently available. Now that neuroscience has mapped cognitive function to the brain dualists are demanding that neuroscientists show how the brain produces the subjective experience of mind.

A more sophisticated “moving goalpost” form of dualism denialism is the claim that all the evidence from neuroscience only shows that brain function “correlates” with cognitive or mind function, and that correlation does not prove causation. No one can now deny, from the copious evidence, that activity within specific locations in the brain correlate with specific mental activities. And here is where we get to the analogy with evolution denial.

Some creationists/ID proponents, such as Michael Behe, accept all the evidence for common descent, for the change in life over time in a branching pattern of relatedness. This nicely accommodates the bulk of the evidence for the fact of evolution. Behe just maintains that the proposed mechanisms of evolution are not adequate to explain this change, that we need to invoke an invisible hand pushing evolution forward. In essence Behe is moving his creationism (the involvement of a creator, or “intelligent designer”) out of the way of all that evidence for evolution.

Also (and more in line with the “correlation is not causation” argument) it is common for creationists to dismiss the existence of transitional forms as mere correlation. For example they say that Archaeopteryx (or Ambulocetus or Tiktaalik) only look as if they are transitional, this does not prove that they actually are transitional (the descendant of one species and the ancestor of another). What they are saying is that even though the anatomy may correlate to what a transitional form would be that does not mean that evolutionary relationships caused that anatomical correlation.

Likewise, some modern dualists acknowledge that brain function correlates to the mind but this does not prove that it causes the mind. Strictly speaking this is true (assuming causation from correlation is a logical fallacy), but it is also a logical fallacy to assume that correlation does not result from causation. Further, we can infer causation from multiple correlations that all point in the same direction. The brain does not only correlate with mind, it does so in every way we would predict from the hypothesis that the brain causes mind. For example, if an independent or separate mind caused changes in the brain (reversing cause and effect) then we would not expect that altering brain function would alter the mind also – but it does. We can use drugs to change brain function, and the mind alters. Damage to a part of the brain damages the corresponding mental activity. Every way we choose to look at it the correlations indicate that the causal arrow is pointing from the brain to the mind.

Does this metaphysically prove that the mind is nothing but brain function? No, science does not deal with metaphysical certitude. However, I think that we can come to two broad conclusions based upon the current state of neuroscience:

1) The “brain causes mind” hypothesis has held up to all scientific observations. Every correlation predicted from this hypothesis has been observed, and there is no established evidence that is incompatible with this hypothesis.

2) The brain is sufficient to explain the mind, meaning that we do not require something other than or more than the brain to explain the phenomenon of mind.

So while some form of dualism cannot be excluded on philosophical grounds, dualism is completely unnecessary. The more modern and subtle forms of dualism do try to account for the evidence of neuroscience, in the same way the Behe tries to account for the evidence of evolution, but still commit some logical fallacies in maintaining that an invisible hand is necessary. And very much like ID proponents, until dualists can propose a testable hypothesis of their position it suffers from the worst of scientific vices – it is not even wrong.