This investigation started with consideration of the biological origins of the mind, then recast and added to that perspective in a philosophical light, and now shall flip back to biology. In doing so there are two benefits: Firstly, one can see how the model described so far is represented within the human brain itself, in part verifying the reason that has led us thus far. Secondly, this comparison will also show gaps in the philosophy and point the way toward a more complete representation. This first section of Biological Correlation shall look at the sense and Entity Interpretation part of the system. On this page, familiarity with the basic nature of the human brain, and on the next, how this relates to the idea of Entities and Interpretation. Before starting proper, there are a few important points to consider when detailing the correlates: The blind watchmaker Firstly, the brain was a product of evolution, and as such was developed through gradual outgrowing, reshaping and repositioning of the interconnections within its structure. Thus, what was evolved first tends to be not discarded but adapted where necessary and incorporated into the new scheme of things. Take for example the vestigial tail in the apes, or the remnant bone structure of ancient hands in the flippers of aquatic mammals. In the brain this has had the similar effect of creating a mass of interconnections that, though elegant in execution as the rest of nature tends to be appreciated, is not the logically simplest way to achieve the end product. Secondly, and related to this point, evolution has "hard-wired" many "instinctive" neural pathways that, though certainly a benefit for living organisms trying to survive and procreate, are equally certainly not a necessity to becoming self-aware. The visual and auditory senses pass through the lateral and medial geniculate nuclei on their way to the cortex, these connections allowing Dasein to turn its head, "instinctively" on a pre-conscious level, towards sudden noises. No doubt a benefit should a lion step on a twig, but something that could be just as left to conscious decision in a synthetic instance of Dasein. These two points, together, tend to make the biological, evolutionarily derived, model of Dasein an order more complex than it need be. Overview The human brain is, for all its cellular complexity, quite a simple structure in the macroscopic. As intimated in the Primer, the brain is an evolutionary response to the need for large, multicellular replicators to coordinate sense and action, and is an outgrowth of the spinal cord. This picture shows a human brain specimen with some cranial nerves, like the optic nerves and eyes, removed. The spinal cord at the bottom is what connects the brain to most of the body, functionally speaking. Upwards from the spinal cord we find the hindbrain, and thence the midbrain and forebrain; in evolutionary terms the spinal cord is the oldest part and the further towards the front, or top depending on the replicator, are more recent adaptations found.  Just as the ubiquitous function of the model is Interpretation, one would expect, should the model be correct, for the cortex to house this function and exhibit associated characteristics. The difficulty of defining Interpretation as a process shall be tackled later, but in the present situation there are features of the cortex that do correspond with what one would expect: The cortex is neuron dense, and has relatively high intra-connectivity, something like 99% of cortical neuron connections staying within the cortex. Also identified on the histological level are small, relatively distinct, collections of neurons that lie "upright" across the transverse layers of cells, called neo-cortical columns, or NCCs. Within the average human these number approximately 500,000 and consist of about 60,000 neurons each. I shall later on argue for these as a candidate basic unit of Interpretation. The above diagram shows the four main, external, lobes of the cortex, the occipital, temporal, parietal and frontal lobes. The diagram below shows the regions of "primary" cortex within each lobe. Within the sensory half, these primary cortical regions are where afferent nerve connections receive data from the body, the eyes and the ears. Within the action half, the primary motor cortex is where the efferent, outgoing, nerves originate, from where they travel to the cerebellum and onto the body.  Summary
Created 27th June 2008 Revised 9th July 2009 |