Neural Darwinism: The Evolution of Truth
Can evolutionary theory build a bottom-up explanation of higher cognitive functions? David Papineau (King’s College) doubts it. In his review of The Physiology of Truth: Neuroscience and Human Knowledge by Jean-Pierre Changeux (transl. Malcolm DeBevoise, Belknap Press: 2004), published in the June 3 issue of Nature,1 he gives the author high marks, but concedes that this neurophysiologist with outstanding credentials falls into the usual trap:
Can neurophysiology cast any light on the human condition? Books that set themselves this ambition, and there are plenty, are invariably disappointing. The problem is not that we lack information at the neuronal level – a great deal is known about cell receptors, neurotransmitters, re-entrant connections and so on. Rather, the difficulty lies in relating this microscopic knowledge to higher human faculties such as thought, emotion and consciousness.
To get round this, popular-science books by the likes of Francis Crick, Joseph LeDoux or Antonio Damasio typically have the following trajectory. We start with a few chapters on the neuronal nitty-gritty. But then the gears surreptitiously change, and we switch to speculation about the mind’s higher powers. However, any serious theorizing at this level tends to be ‘boxological’, rather than physiological — we are given flowcharts connecting posited brain modules, but there is no bottom-up, cell-level account of how these modules might work.
Perhaps this is unsurprising, given the kind of evidence that is currently available about the large-scale operations of the mind. In recent years, functional-imaging data have been added to findings from studies of brain lesions. But even these new data are at too gross a scale: it is like trying to figure out how a computer works by noting when different bits get hot and what goes wrong when certain parts are broken. With luck, this might give us some idea of where certain operations are located, but it is not going to tell us about the mechanisms that make them possible.
So is the mind Freud’s black box? Cognitive psychologists seem to be in the same boat as the evolutionists Michael Behe described in Darwin’s Black Box. They can watch the inputs and outputs, but have no idea how to get from one to the other; they end up with vague, handwaving, “boxological” explanations. That does not prevent Changeux from proposing a “neural darwinism,” a tentative mechanism based on “selective favouring of some spontaneously formed synaptic connections over others during development.” Papineau is unconvinced this makes any progress.
Changeux has plenty to say about neural darwinism, and touches on functionalism [the belief no molecular mechanisms can explain higher cognitive functions] in passing, but he doesn’t quite spell out the connection between them. Still, his book presents a more satisfying picture of the brain than most of its competitors in this crowded market. On standard accounts, it can simply seem frustrating that we never get any bottom-up explanations of higher cognitive functions. If the structure of the brain is laid down by a definite genetic plan, then why can’t we find out about the underlying mechanisms? Changeux’s book fails to identify any such mechanisms too, but at least he gives us some insight into why the search for them may be doomed to permanent frustration.
David Papineau, “Mind the gap,” Nature Nature 429, 505 – 506 (03 June 2004); doi:10.1038/429505a.
If truth evolves, it isn’t the truth. As usual, Darwinists want to explain everything, even the intangibles, in terms of unguided materialistic processes. But in the area of the mind, have they even begun? Papineau says no, despite the crowded market of contenders; they all reveal it to be an exercise in “permanent frustration.” The result is simplistic just-so stories, as unsatisfying as “presto, Changeux.”
We know the mind influences the body, and the body influences the mind, but neither can be reduced to the other. Consider what a conundrum it must be to a materialist to realize that though our individual brains are composed of quadrillions of neurons, which all join together in unique ways during development – making each of us one-of-a-kind in the universe – we still can hold conversations and understand quite a bit about each other. Scientists can peer review each other’s papers and judge the merits of their arguments. That indicates that the capacities for relationships and logical thinking were designed into us from the beginning. It also points to an intangible nature expressed through, but not reducible to, our bodies. We also have a sense of self, a conscience, and a hunger for ultimate meaning. None of these can be reduced to molecules.
The Bible teaches that we are more than matter in motion. To a dichotomist, we have a body and soul. To a trichotomist, we have a body, soul and spirit. Either way, we are not just a body. According to the Bible, the spirit of Jesus Christ existed eternally from the beginning (John 1). He inhabited a physical body for a time, but His spirit remained alive while his body was dead (I Peter 3:18-22), and then returned into His body during His resurrection. This means our soul and/or spirit can endure apart from the atoms and molecules of our bodies. Even if the whole world melted in a nuclear holocaust, our natures would live on (II Peter 3:8-13). What a profound thought: we’re going to live somewhere forever. It makes good sense, therefore, to learn how to live. We will all be doing it, one place or the other, for a long time.
Suggested reading: Ecclesiastes 12, I John 5.