How does Epistolution Explain Lateralization?
The human brain, and the brains of all other highly intelligent animals, is divided in half, into two hemispheres that are quasi-independent. This is a very puzzling architecture. Why should a perfectly functional brain be doubled into two brains? The brain is an energetically expensive organ to maintain, and redundancy is the obvious first guess, and perhaps this provides part of the answer. But the two hemispheres are not entirely redundant. Rather, as Iain MacGilchrist has brilliantly explored in his book, The Master and His Emissary, the two hemispheres of the neocortex see the world quite differently. The reductionistic hemisphere, in most humans the left, is the predatory side of the brain, which picks out details of the world and manipulates them. This is the side used by animals for picking out their food and consuming it. The holistic hemisphere, in most humans the right, is the prey side, which is sensitive to the entire context of one’s environment and actions, and their meaning within that context. This is the side which understands that the flick of an ear means a predator is lurking in the underbrush. Epistolution is a theory of how meaning can be embodied by a living structure, by the sensitivity to the larger context of the niche. This is essentially the way the right hemisphere processes the world, as a whole. The cognitivist view, on the other hand, sees general intelligence as a highly developed machine for manipulating symbols, which is a very left hemisphere way of doing things. In the cognitivist view, intelligence consists of building up the world from separate isolated engrams, reference frames, or algorithms. It focuses on the neuron as a building block, and the brain as a structure. Epistolution, on the other hand, focuses on the niche as the creative device, and posits that all living bodies of any species are set up to be servants of their niches. This provides a sort of universalism to intelligence, an egalitarianism among living creatures. Everything living has some intelligence in the epistolution view, only some living creatures are in niches which particularly reward collaborative, far-sighted, concerted expect-actions. Lateralization of the brain makes sense if the same dataset must be processed in two fundamentally different ways, one way to provide reductionistic manipulation of detail, and the other to provide holistic synthesis of meaning and morality.
One hemisphere of the brain (in humans, the right) is configured to be sensitive to slight alterations in the expected patterns of a broad array of inputs, while the other (the left) is configured to be sensitive and to focus strongly on the single most noteworthy stimulus in the attention field. This corresponds to the evolutionary need for nearly all organisms to use different attention thresholds for the activities of predation/eating versus social/situational awareness, yet use the same streams of whole-body sensation for both. This bifurcation must be absolutely essential to “get a grip” on the world. It has convergently evolved also in octopuses, which have eight “brains” in their tentacles to attend to details, and one in their main bodies to attend to the whole. This is entirely logical, since attending very vaguely to only to slight surprises in the overall flow of life (the holistic right hemisphere) would lead to obliviousness to salient details, like food or predators, while attending only to the most salient details in order to manipulate them intensively (the reductionistic left hemisphere) would lead to complete inattention to the overall context one is living in. These two forms of sensitivity are incompatible, there is no way for one brain to do both well. This must be why all known highly intelligent nervous systems are divided along this axis.
