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The neocortical Darwin Machine theory seems to me to be at the right level of explanation; it's not down in the synapse or cytoskeleton but up at the level of dynamics involving tens of thousands of neurons, generating the spatiotemporal patterns that are the precursors of movement - of behavior in the world outside the brain. Moreover, the theory is consistent with a lot of phenomena from a century of brain research, and it's testable (with some improvement in the spatial and temporal resolution of brain imaging or microelectrode arrays)

Composite cerebral codes, formed by superpositions and shaped up by darwinian copying competitions, could explain much of our mental lives. The codes themselves are suitably arbitrary, just as a century of argument about symbols has emphasized. Copying competitions suggest why we humans can get away with many more novel behaviors than other animals (we have offline evolution of nonstandard movement plans). It suggests how we can engage in analogical reasoning (relationships themselves can have codes that can compete). Because cerebral codes can be formed from pieces, you can imagine a unicorn and form a memory of it (bumps and ruts can reactivate the spatiotemporal code for unicorn). Best of all, a darwinian process provides a machine for metaphor: you can code relationships between relationships and shape them up into something of quality.

Resonances are better known these days as attractors; I imagine each hexagon's neural network as supporting a number of characteristic spatiotemporal patterns, just as spinal cord circuitry supports a number of gaits, the particular spatiotemporal pattern that you get depending on how you precondition the circuitry via the facilitation from other imposed patterns. And that may have something to say about the "stream of consciousness."

Manipulating the landscape of a basin of attraction is reminiscent of William James's train of thought, that series of mental states that preceded your current one, each one fading into the background but overlain on its predecessors - and all capable of contributing to what connections you're likely to make right now.

Just imagine those various fading attractors as like that Japanese technique of finely slicing some raw fish, then tilting the block sideways (fallen dominos are another analogy, if you are sashimi impaired). The bottom layer may be hardest to reach but it goes back furthest. Stage-setting with multiple layers of fading schemas may be handy for promoting creativity, getting the right layers of attractors in about the right order and so adjusting their relative strengths. (The Sashimi Theory of Creativity would, of course, be a suitably raw successor to all those half-baked right-brain schemes)

But such histories can also be distracting, and we often try to let them fade, try to avoid reexciting them with further thinking. There are various mind-clearing techniques; Donald Michael10 suggests that forming large quasi-stable hexagonal territories might be what meditation with a mantra is all about, preempting the everyday concerns that would otherwise partition the work space and plate out new short-term attractors. By replacing it all with the mantra's nonsense pattern, and holding it long enough for neocortical LTP to fade, the meditator gets a fresh start (for things other than the mantra!)

An ordinary mantra won't, of course, wipe the work space clean: to prematurely erase those fading attractors, you'll need a fancier mantra that disrupts instead. Short of fogging with seizures, as in electroshock therapy, I don't know of any such eraser schemas - though one can imagine mental viruses11 that might preempt entry into those fading basins of attraction, more analogous to an obscuring coat of paint than to a true eraser.

Once they finish with things as basic as perceptual transformations and memory phenomena, theories of brain function must explain abstractions and associations as diverse as categories, abstracts, schemas, scripts, syntax, and metaphor. If we are to venture past the elementary notion of consciousness as mere awareness or shifting attention, we are going to need to account for all of higher intellectual function (language with syntax, structured planning ahead, logical chains of reasoning, games with arbitrary rules, music). That's the kind of coverage needed for a useful theory of consciousness (and this neocortical Darwin Machine enables predictions to be made, all across this spectrum). It may not have to explain all of two centuries of neurology, one century of psychology, and a half-century of neurobiology and cognitive neuroscience - but it can't be truly inconsistent with any of it. A theory of consciousness needs a lot of explanatory power, while still being specific enough to make experimental predictions

Let me turn now to how complex patterns might self-organize, using such Darwinian competitions to embed suitable resonances in the neural feltwork as we gain experience.

Our passion for discovering patterns seems to have a lot to do with our notions of consciousness. If we are to have meaningful, connected experiences - ones that we can comprehend and reason about - we must be able to discern patterns to our actions, perceptions, and conceptions. Underlying our vast network of interrelated literal meanings (all of those words about objects and actions) are those imaginative structures of understanding such as schema and metaphor, such as the mental imagery that allows us to extrapolate a path, or zoom in on one part of the whole, or zoom out until the trees merge into a forest.

Early childhood contains a number of pattern-finding challenges, and children seem extraordinarily acquisitive of ever-more-complex patterns hidden in the sounds and events that surround them. In our first year of life, we discovered phonemes within words. A year later, we were busy discovering schemas and syntax within sentences, and then we went on to discover narrative principles among more extended discourses. The hexagonal superpositions, so like the different voices of a symphonic performance, show us a way that new associations can be represented in the brain - and the Darwinian aspect suggests how quality could be shaped up via the usual variation, competition, and inheritance.

When we think seriously as adults, we think even more abstractly. We conjure up simplified pictures of reality called concepts or models. We can even discover patterns in speculative scenarios, as when we create a forwards-leaping chain of inferences (especially handy for speculating about consciousness!). As Paul Valéry once said, thought is all about "that which does not exist, that which is not before me, that which was, that which will be, that which is possible, that which is impossible."

Passive awareness (and its neural correlates) may be much simpler than the creative constructs implied by the James-Piaget-Popper levels of consciousness; a pop-through recognition of a familiar object may not need to utilize a cloning competition with alternatives in the manner of an ambiguous percept or a novel movement. Hexagonal mosaics surely aren't everything going on in the brain; indeed, they are probably just one mode of operation of some expanses of neocortex, and regulated by other brain regions such as hippocampus and thalamus. But here-this-minute, gone-the-next mosaics seem quite suitable for explaining many aspects of mind, aspects that have been difficult to imagine emerging from quantum mechanics, chemistry, neurotransmitters, single neurons, simple circuits, or even the smaller neocortical modules such as minicolumns. In some regions, at some times, hexagonal competitions might be the main thing happening.

There emerges from this view of our brain, with its relentless rearrangement from moment to moment, some glimpses of the neural foundations on which we construct our utterances and think our thoughts, some possibilities for implementing our kind of language and rational thought. Dueling choirs are at a level of explanation that looks as if it might be appropriate; we'll have to see just how far we can go with their Darwinian aspects as an explanation for talking-to-yourself consciousness.


(Note: a graphical version of this talk can be viewed at http://williamcalvin.com/1990s/1998TucsonConsciousness.htm)

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