Gerald Edelman - selection and re-entry

Gerald Edelman






Edelman attaches great importance to higher-order processes - concepts are maps of maps, and arise from the brain's recategorising its own activity. Concepts by themselves only constitute primary (first-order) consciousness: human consciousness also features secondary consciousness (concepts about concepts), language, and a concept of the self, all built on the foundation of first-order concepts. 

The final key idea in the theory, another one with a slightly misleading name isvalue, a word used here to describe inbuilt tendencies towards particular behaviour. These forms of behaviour may be driven by what we value in a fairly straightforward sense - seeking food, for example, but they also include such inherent actions as the hand's natural tendency to grasp. Edelman seems to think that, like a computer, if left to itself the brain might sit and do nothing. It's the value systems which supply the basic drives. This sort of set-up has been modelled in a series of robots rather cheekily named Darwin I to IV.





Blandula   The argument is a bit more specific than you make out. Edelman points out that the selective processes he has in mind have an unusual feature he calls 'degeneracy' (I'm not quite sure why). Degeneracy means that the same output can be reached in a whole range of different ways. This is a feature of the immune system as well as mental processes, but it doesn't look much like an algorithm. Of course there are other arguments against considering the brain a computer, but I think Edelman's main point is that to deal with reality, you have to be able to arrange the streams of mixed-up and ever-changing data from the senses into coherent objects. Your computer with a camera attached finds this impossible except in cases where the 'reality' has been made artificially simple - a 'toy world' - and the computer has been set up in advance with lots of information about how to recognise the objects in the 'toy world'. I know you're going to tell me that great strides have been made, and that you only need another couple of decades and it'll all be sorted. 


Bitbucket  I wasn't, though it's true . I was just going to point out again that, however difficult it may be to digest reality, Edelman gives us no definite reasons to think computers couldn't do it; his robots even demonstrates some aspects of the methods he thinks most likely. But never mind.You expect me to attack Edelman just because he and Searle have spoken favourably of each other: but actually I've got nothing much against him except that I think he's misunderstood the nature of computationalism.  Just because we haven't got USB ports in the back of our heads it doesn't mean brain activity isn't computable. 

As for that bit about 'degeneracy', I don't see it at all. Imagine we had a job we wanted done by computer - we call in a hundred consultants to tender for the project. They'll find a hundred different ways to do it. Even if we set aside most of the possible variation - whether to use PCs, Macs, Unix boxes or what, Java, C++, visual Basic or whatever. Even if we assume the required outputs are narrowly defined and all the tenderers have to code in bog-standard C, there'll be thousands of variations. So I reckon computers can be degenerate too... 


Blandula  I don't expect you to attack Edelman at all. As a matter of fact, I'm not an unqualified admirer myself. Take his views on qualia. The temptation for a scientist is always to miss the point about qualia and end up explaining the mechanics of perception instead (a different issue) Edelman, in spite of his scientist bias, is not philosophically naive and a lot of the time he seems to understand the point perfectly. But in 'A Universe of Consciousness' he swerves at the last minute and ends up talking about how the neurons could map out a colour space - which might be interesting, but it ain't qualia. Perhaps his co-author is to blame.

However, I'm with him on the computer issue. Edelman's views about selection illustrate exactly why computers can't do what the brain does. I think his ideas on this are really important and have possibly been undersold a bit. The thing about programming a computer to deal with real situations is that you have to anticipate every possible kind of problem it might come up against - but there are an infiinite number of different kinds of problem.  Now this is exactly the kind of issue the immune system faced: it had to be ready to deal with any molecule whatever, no matter how novel. The solution is analogous: the immune system fills your body with a really vast number of variant antibodies; your brain is full of an astronomical number of different neuronal patterns. When the problem comes along, even a completely novel one, you're going to have the correct response waiting somewhere: and the one that matches gets reinforced and reused. Edelman called this a Darwinian process: it isn't really (hence Crick's joke about it really being 'neural Edelmanism'): the remarkable thing is, it might be better than Darwinian in this context!


Bitbucket   Anything's better than Darwin to you, up to and including spontaneous generation and Divine Creation. 


BlandulaNonsense! But, honestly. It's not particularly original to suggest that the mind might use selective or Darwinian mechanisms, (or be infected with memes evolved in the memosphere) but normal Darwinian selection is just obviously not the answer. When we confront a sabre-toothed tiger or think what to say to a question in an interview, we don't start by copying some earlier response, try it out repeatedly and gradually refine it by random mutation. We don't even do that in our heads, normally. 99% of the time, the response is instant, and appropriate, with nothing random about it at all. It's a bit easier to understand how this could be so on the Edelman theory, because some reasonably appropriate responses could already be sloshing around in the brain and the best one could be reinforced very quickly. 


Bitbucket  I think you're going further on that than Edelman himself would be inclined to do. In fact, I'll give you a prediction. Eventually, Edelman himself will come round to the view that there is nothing unique about all these processes, and that while the brain may not be literally a computer, its processes are computable. 


Blandula I think not. You ought to remember what the man said himself about changes of heart - the unit of selection in successful theory creation is usually a dead scientist...



"Bright Air, Brilliant Fire"
The most accessible account of the TNGS. Although Edelman's theory is very much a matter of neurons, the details are balanced with some philosophical and other general background and lightened with the occasional joke. 

"Neural Darwinism", "Topobiology", and "The Remembered Present"  
This trio together make up the authoritative account of Edelmanism. If you want the full version, this is it.
"A Universe of Consciousness" 
Written with Giulio Tononi. Same theory, narrower focus, different emphasis. Those who think qualia are the real issue, or have a particular interest in the binding problem might prefer this version.

"The Mystery of Consciousness" 
This collection of pieces by Searle about noteworthy conscious entities includes a friendly summary of Edelman, whose emphasis on biology is congenial to Searle.

"Wider than the Sky: The Phenomenal Gift of Consciousness" 
Edelman's latest book focuses on phenomenal experience, but it summarises a lot of his thinking in a relatively small space - perhaps a good place to start on Edelman or get a better idea of what he's on about.

LinksSome Links:
Short biography : from a conference site.
Page at Princeton - complete with mugshot of the youthful Edelman

Review of 'A Universe of Consciousness' - from the Guardian. Rather unenthusiastic, but some sound points.