There are many, many different ways of implementing consciousness, each with its own advantages and weaknesses, and it may well be that lots of them have been tried out during the course of evolution. So say Rodrick Wallace and Roger G. Wallace, in a paper (pdf) full of daunting mathematics and airy speculations.
The Wallaces take Bernard J Baars’ Global Workspace theory as their starting point. The Global Workspace theory sees consciousness as providing a general access function: a fleeting memory capacity that connects brain modules that otherwise function separately. It’s as though consciousness were a noticeboard where the different functions can post problems, warnings, discoveries and data which other functions may be able to use or respond to. Consciousness is there to provide an overall integrative function.
The Wallaces have developed a detailed analysis of the requirements of such a function, and they have come to the conclusion that many different architectures and organisations are capable of giving rise to something with the essential properties. Indeed, they see no barrier to a slow form of consciousness in all sorts of creatures: a kind of ‘paraconsciousness’, as they call it. The details of this notion are tantalisingly vague, but it seems the idea is that even trees might have processes which allow them a very slow and very dim kind of awareness. The Wallaces also see analogues of the Global Workspace in systems made up of multiple organisms: societies or ant colonies. The idea that such higher-level systems have at least some of the properties of consciousness is reminiscent of Ned Block’s ‘Chinese Nation’ thought experiment, in which the whole population of China is somehow dragooned into hand-simulating the nervous activity of a brain. The Chinese Nation idea, however, was supposed to demonstrate the weakness of functionalism by pointing out how absurd it is to think that this kind of gigantic hand-simulation of mental functions would give rise to anything like a mind. I suppose this perhaps shows how different our perceptions of intuitive plausibility can be.
The idea of higher level workspaces has a role, however, in overcoming some of the objections to the Wallace’s ideas. The most obvious objection, of course, is that they take the Global Workspace for granted: they say it is rapidly becoming the most favoured model among researchers, but even if that is true, it’s a long way short of being established. It remains quite possible that the theory is entirely wrong; or perhaps more likely, that an integrating function does exist, but does not constitute consciousness.
At the risk of being speciesist, it certainly looks as if the Wallaces are thinking of a form of consciousness somewhat short of the grand human version we are normally concerned with: they readily attribute it to a range of animals all the way down to cephalopods (who would surely achieve consciousness through a very different organisational structure from ours, given their tendency to rely on large neural ganglia distributed around the body rather than just a single central brain).
In fact the Wallaces are primarily interested in the palaeontology of consciousness, the road to which is, they say, wide and open (A rather optimistic conclusion, I think, since about the best evidence we can hope for is the shape of a fossil skull. The Wallaces’ own conclusions reinforce the common sense assumption that you can’t tell much about how a strange brain may have worked merely from its shape) . What strange forms of intellect may have flourished during the great Cambrian explosion, when many bizarre animals with strange body plans flourished!
However, they do have a view about the special qualities of purely human consciousness, and this is where the higher level workspaces come in. It is likely that all the different forms of consciousness tried out by evolution had different strengths and weaknesses: most would have suffered from some areas of ‘inattentional blindness’, but the creatures that had the smallest blind spots in the least important places would have survived best. Perhaps the unique trick of human consciousness, the one which fitted it for a distinctly human way of surviving, was to have a special facility for tuning in to higher-level workspaces: for fitting into complex societies and networks of communication and decision making.
This idea is more or less an aside in the Wallaces’ paper, but I can see some appeal in it, and I suspect it might in fact provide a more fruitful avenue to pursue than the attempt to reconstruct the minds of Acanthostega or Tulerpeton.