The Emergent Evolution of the Soul in the Neocortex

In Darwinian Conservatism, I have a chapter on "Emergence" (104-111). Against the charge that Darwinian science is reductionistic because it denies the uniqueness of human mental freedom in denying that the mind has any freedom from the material mechanism of the brain, I argue that Darwinian evolution actually denies both reductionism and dualism and sustains the idea of emergence as a third alternative.

The simplest expression of the idea of emergence is that the whole can be greater than the sum of its parts. As we pass through levels of complexity in evolution, we see new properties at higher levels that are not fully reducible to the lower levels. That's why, for example, biology is not fully reducible to physics and chemistry. So the idea of emergence denies strong reductionism, because it denies that the higher levels of organization can be completely reduced to the lower levels. But the idea of emergence also denies dualism, because it denies any radical separation of matter and mind.

Part of my argument here concerns the "emergent evolution of the soul in the brain" (109-111). We should say that only human beings have a soul, which gives them an intellectual and moral freedom that other animals do not have. And we should explain this soul as an emergent product of the evolution of the brain once it passed over a critical threshold of size and complexity in the neocortex, particularly in the frontal lobes.

The evolution of the primate brain shows a trend towards increasing size and complexity of the neocortex, which allows for greater behavioral flexibility in these animals. This trend reaches its peak in the human brain. Larger and more complex frontal lobes give animals the capacity for voluntary action, in the sense that they can learn to alter their behavior in adaptive ways. In human evolution, the growth in the size and complexity of the frontal lobes passed over a critical threshold allow human beings to use words and images to compare alternative courses of action through mental trial and error. Consequently, human beings are capable not just of voluntary action but of deliberate choice, by which they self-consciously choose present courses of action in the light of past experiences and future expectations to conform to some general plan.

Recent research in neuroscience on the evolution of the neocortex gives some support to this kind of reasoning. A short review of this research is Pasko Rakic's article "Evolution of the Neocortex: A Perspective from Developmental Biology," Nature Reviews Neuroscience, 10 (October 2009): 724-35. Here's the abstract for the article:

"The enlargement and species-specific elaboration of the cerebral neocortex during evolution holds the secret to the mental abilities of humans; however, the genetic origin and cellular mechanisms that generated the distinct evolutionary advancements are not well understood. This article describes how novelties that make us human may have been introduced during evolution, based on findings in the embryonic cerebral cortex in different mammalian species. The data on the differences in gene expression, new molecular pathways and novel cellular interactions that have led to these evolutionary advances may also provide insight into the pathogenesis and therapies for human-specific neuropsychiatric disorders."

Normally, this article would be available only to subscribers. But for the next six months, it can be accessed online along with some other articles on the evolution of the brain.

Some previous posts related to this topic can be found here, here, and here.