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Archive for 19/12/2009

The missing hierarchical level


One of the problems with neural research is that there is a missing hierarchical level. To explain this I have to discuss the nature of science. The basic idea of science is to gather data (or facts, or observations) by investigations and then explain the the data with theories about the nature of the physical world. I know, I know; this is a very simplistic description, but it will do for now.

The larger the range of data explained by the theory, the more accurate the predictions that the theory makes and the more consistent the theory is with other knowledge (mathematics, logic, other established theories), than the better (or the more convincing and useful) the theory. Each large theory has its own model of how the physical world works; it has its own vocabulary of words and concepts; it has its own tools, methods and instruments; it has its own rules, laws and relationships. There is actually very little overlap between theories, but some. So for instance, the theory of plate tectonics and the theory of evolution by natural selection are very different. One can discuss either of them for days on end without needing to refer to the other one. But they do overlap when location or time of events in their narratives overlap or where their casual links entwine. These are sister theories, more or less at the same hierarchical level. However, not all theories are on the same hierarchical level. Theories can only overlap if they are on the same level or adjacent levels.

If we are looking at evolutionary biology and we want to explain the nature of fitness, we have to drop out of evolutionary biology into the level of functional physiology in order to see the functioning of the eye producing sight and how this helps an animal to survive. If we then want to talk about the changes that have occurred in eyes, we have to drop down another level to the cellular level with its overlapping theories of biochemistry, biophysics and genetics. For a deeper explanation we would drop down to macro chemistry and physics and then down to atomic physics and then sub-atomic physics. But you cannot jump over a level. You cannot get any reasonable explanation of physiological function from the concepts of sub-atomic physics – there is no overlap.

When we look at the brain/mind, we are missing an important level. On the one hand, there is behavior, ideas, emotion, cognition with theories in psychology, ethology, anthropology, philosophy and so on. On the other hand there is neurobiology, mostly at the cellular level. There is no overlap between the wet and squiggly neuron in brain tissue and the dry abstractions of a ‘black-box’ mind. There is experimental evidence for the very close connection between the brain’s activity and the mind but there is no accepted theory that bridges that gap.

What would such a theory look like? It would be about the functional physiology and anatomy of medium and large groups of neurons and in particular how they manipulate information. It would be about how the concepts of mind are manifested in neural activity.

One way to understand something is to try and make it. That is why creating artificial intelligence, work with neural networks, attempts to accurately simulate small areas of brain tissue and the like will contribute. Another approach is to study very simply ‘brains’ and completely understand how they function before climbing the stairs to ever more complex brains, trying to get a complete understanding at each level. Also, many are going to keep collecting data on connected events at the mind and brain levels, looking for generalizations and patterns. There is little doubt that the tools that exist today, primarily various kinds of scans and electrical recordings, will be improved and new types added. A few ‘eureka’ ideas will get investigators out of old habits of thinking.

Everyone is entitled to their opinion, but frankly it is not helpful to those looking for a theory that bridges the gap when someone stands to the side and says that such a theory is impossible. In effect they are saying that it can’t be done because no one has ever done it. Until recently, no one has tried very hard. Now quite a few are trying.

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