Indeed, breaks new ground - Rated 
I've come to this book as someone who has been reading about consciousness and the mind-body problem since encountering Descartes and Locke in my University days. Hi-lites on the way have been Dennett's Consciousness Explained (not) and Chalmers' Conscious Mind. After reading several recent Philosophy titles, including Kim's Philosophy of Mind I was getting the feeling that the Philosopher's were getting bogged down.
Edelman and Tononi are writing from the leading edge of Neuroanatomy and present a fascinating and extremely readable account of the architecture of the Human Brain and indeed Monkey and Cat brains, which we are starting to map out in great detail now. For this account alone the book gets its five stars. The bulk of the book then builds on this to present a theory of what consciousness, considered as a process, is from a neurological perspective. In brief, the brains of higher mammals who enjoy primary consciousness, that is conscious experience of their sensory modalities and a range of emotional states, are mostly made up of the cortex and the thalamus which implements hundreds or thousands of tiny little modules, all with very specific functions like, identifying colours and lines and so on. If we then imagine there to be a cloud of such modules and then imagine that each module is connected by a mesh of fibres to some, possibly many of the other modules. It is evidently the case then that when we are awake or dreaming in REM sleep, the modules are all beavering away doing their tasks and there is a vast amount of bi-directional traffic on this mesh connections. When we are in deep NREM sleep or in seizures like epilepsy, where consciousness is lost, then the modules are all still working away but the traffic on the connections is off. Whatever consciousness is, the authors are saying, then this is what distinguishes conscious and unconscious mental states in the brain's operation. The system operates such that no overall process is in charge but behaviour emerges from the interaction between the dumb modules according to rules not yet understood.
They work this and a lot of other detail up into a theory which they call they Dynamic Core Hypothesis, the first big result of which is that consciousness cannot be identified with particular neurons, types of neurons or areas of the brain. Consciousness arises from the constantly shifting pattern of activation between the many modules along what they call the re-entrant connections between them. When the pattern switches off, or slows down beyond a certain rate, then so does consciousness. This to me was all fresh knowledge and magnificent stuff.
The latter part of the book includes speculations on the evolution of consciousness, including what he calls the secondary or higher consciousness which only humans have. This would plausibly seem to have arisen first with language, followed by the internalisation of language, followed by thought, which gives rise eventually to the discovery or invention of logic and mathematics. They stress that there was no 'logic', in the formal sense, going on anywhere in the universe until thought arose. This is part of their strongly held position thet the brain IS NOT a computer.
And for me this is the nub of the book. Part of the theory they present is the Theory of Neural Group Selection (TNGS) which is based on observations of the development over time of axons and dendrites down in the neurons in response to patterns of stimuli. While TNGS presents the way neurons operate and what the brain needs to be doing as a whole, it doesn't really have much to say about how the changes going on in the neurons are doing what they need to do. Eventually in the book we are at a stage where they declare that the brain is not a computer in the strict sense of not being a Turing machine, but is rather a selectional system. They make much of the contrast between Turing machines (based on logic) and Selectional systems but, I may have missed something here, the workings of a 'selectional' system, as presented, are not clear enough to say whether what they do could or could not be carried out by a Turing machine. To claim that any information processing system IS NOT a Turing machine, I would have thought, requires a formal mathematical description and proof. What does the 'selectional system' do that a Turing machine can't? Can a selectional system tackle classes of problem that are incomputable by Turing machines? And so on.
Nonetheless a facinating read. The first seventy pages or so were very easy going but once we got into the nitty-gritty it became a demanding book, requiring the kind of slow methodical approach that a proper philosophy text demands. I have seen Edelman criticised that his style includes a lot of repetition of terms and definitions. I actually think that this is appropriate because he is trying to be as unambiguous as possible about concepts that are notoriously slippery.
A fine, fine book. It will be while before I go back to reading a Philosophy of Mind text. Hopefully when I do the philosphers will have found something new to say.
This could be the new paradigm - Rated
Having been pretty much a devotee of "airy-fairy" philosophical explanations of memory, learning, consciousness and psychopathology, I picked up this book with some hesitation. However, it seems that Edelman and Tonio are really onto something. Something so profound that it may be that all future mental health and education theories use it as the new paradigm that unites or dismisses previous explanations. However, it does open the way for more airy fairy philosophical debates about, if forward movement is merely a concept made of linked neuronal maps, what the external world is really like. Or if it is at all. Anyway, great thought provoking and very satisfying book.
|
