This is a big topic, of course. The brain, like all of biology, is obviously intelligently designed. From the elegant coordination of neural activity between neurons and brain regions to the remarkable law-like behavior of individual molecules and atoms that comprise neurons and neurotransmitters, the brain carries the unmistakable fingerprint of a Designer. But there is another common-sense way to infer design of the brain that is simple and I think quite convincing — it is based on our belief that our perceptions and concepts accord with truth.
To see how this points to intelligent design of the brain, consider a very compelling argument for God’s existence proposed by philosopher Richard Taylor (1919–2003) in his book Metaphysics. Thomist philosopher Edward Feser has a nice synopsis and commentary here. I paraphrase Taylor’s argument:
Imagine that you are on a train in England and you see a collection of stones on a hillside that says THE BRITISH RAILWAYS WELCOMES YOU TO WALES.
In theory there would be two ways that the stones could be arranged that way. One way would be if they were deliberately arranged by an intelligent agent to convey the message that you are entering Wales. The other way would be that wind and rain randomly moved the stones so they resembled a meaningful message but in fact had no intelligent source. The likelihood of either possibility is irrelevant to the argument.
Now you could believe, based on the stones, either that you were in fact entering Wales or you could not believe that. Whichever you believe is also irrelevant to the argument. Taylor’s point is that you could not justifiably believe that the stones came to be by random arrangement and at the same time believe that they were conveying the message that you are entering Wales. That is, you are only justified in believing semantic content conveyed by matter if the arrangement of the matter is intelligently designed.
Taylor now draws an analogy to the neurological processes of our brain. We believe the messages conveyed by our neurophysiology — by the arrangement of our neurotransmitters and our neurons. If these brain functions evolved by Darwinian evolution — that is, they came to exist as a result of unintelligent, random, heritable variation and natural selection — then you could have no justified belief that the perceptions and concepts generated via your brain have genuine meaning. It would be irrational to ascribe semantic content to a material process that lacks an intelligent designer.
Taylor uses this argument to argue for God’s existence. When we believe that our perceptions and concepts point to the truth, we implicitly acknowledge the existence of God who designed them. If the neurophysiology that generates our perceptions and concepts were not intelligently designed, we would have no justified reason to believe that they point to truth, anymore than we would have justified reason to believe that and unintelligent conglomeration of stones tells us where we are in England. It is a quite good argument for God’s existence, and of course it is also a good argument for the intelligent design of the brain.
Note that this argument puts those who deny God’s existence in a difficult rhetorical position — if they deny God’s existence, they cannot believe that their perceptions and concepts have any orientation to reality.
Ed Feser in his commentary on Taylor’s argument discusses a number of objections that might be raised to Taylor’s analogy. He points out that none of the expected arguments succeeds. For example, an atheist might argue that we have justifiable inductive reasons for trusting our senses and concepts, even if our brains are not intelligently designed because we have daily experience that our perceptions and concepts correlate with reality. But this is merely to argue in a circle. If our brain is not intelligently designed to begin with, we have no justification for trusting our inductive reasoning process or perceptions.
Taylor’s argument for God’s existence is also a good argument for intelligent design of the brain. As I noted, the evidence for intelligent design of the brain is massive and undeniable, just as it is for all aspects of biology. The nice thing about Taylor’s argument is that it logically compels atheists and others who deny intelligent design to also deny their capacity to know reality and truth. Of course, the lack of the capacity to understand reality and know truth is a hallmark of atheism and of the denial of intelligent design, and Taylor’s argument provides a clear and quite clever way of pointing that out.
You may also wish to read: My challenge to two atheists who deny free will There is too much of this nonsense in the science blogosphere. If Pigliucci or Coyne would like to debate free will, they can consider this a challenge from me. Free will has no physical cause? At least four categories of events in nature have no physical cause. Free will denial isn’t science, just atheism in a lab coat. (Michael Egnor)