``Neural Darwinism
Edelman's theory of neuronal group selection, also known as Neural Darwinism, has three basic tenets -- Developmental Selection, Experiential Selection and Reentry.
* Developmental selection -- the formation of the gross anatomy of the brain is controlled by genetic factors, but in any individual the connectivity between neurons at the synaptic level and their organisation into functional neuronal groups is determined by somatic selection during growth and development. This process generates tremendous variability in the neural circuitry -- like the fingerprint or the iris, no two people will have precisely the same synaptic structures in any comparable area of brain tissue. Their high degree of functional plasticity and the extraordinary density of their interconnections enables neuronal groups to self-organise into many complex and adaptable "modules". These are made up of many different types of neurons which are typically more closely and densely connected to each other than they are to neurons in other groups.
* Experiential selection -- Overlapping the initial growth and development of the brain, and extending throughout an individual's life, a continuous process of synaptic selection occurs within the diverse repertoires of neuronal groups. This process may strengthen or weaken the connections between groups of neurons and it is constrained by value signals that arise from the activity of the ascending systems of the brain, which are continually modified by successful output. Experiential selection generates dynamic systems that can 'map' complex spatio-temporal events from the sensory organs, body systems and other neuronal groups in the brain onto other selected neuronal groups. Edelman argues that this dynamic selective process is directly analogous to the processes of selection that act on populations of individuals in species, and he also points out that this functional plasticity is imperative, since not even the vast coding capability of entire human genome is sufficient to explicitly specify the astronomically complex synaptic structures of the developing brain[11].
* Reentry -- the third tenet of Edelman's thesis is the concept of reentrant signalling between neuronal groups. He defines reentry as the ongoing recursive dynamic interchange of signals that occurs in parallel between brain maps, and which continuously interrelates these maps to each other in time and space (film clip: Edelman demonstrates spontaneous group formation among neurons with re-entrant connections [12]). Reentry depends for its operations on the intricate networks of massively parallel reciprocal connections within and between neuronal groups, which arise through the processes of developmental and experiential selection outlined above. Edelman describes reentry as "a form of ongoing higher-order selection ... that appears to be unique to animal brains" and that "there is no other object in the known universe so completely distinguished by reentrant circuitry as the human brain".''
http://en.wikipedia.org/wiki/Gerald_Edelman
I just looked up Gerald Edelman because Ian mentioned him here:
``Or are you intimating your curiosity on the Searle-Putnam collaboration with Gerald Edelman re "Neural Darwinism" which has this little gem tucked in the first few pages?
``The position I will take here is that this is just the case: the environment or niche to which an organism must adapt is not arranged according to logic, nor does it have absolute values assigned to its possible orderings...When we consider the world, there is no given semantic order: an animal must not only identify and classify things but also decide what to do in the absence of prior detailed descriptive programs[.] [GE, ND pages 24-26] '' (Ian)
http://mailman.lbo-talk.org/pipermail/lbo-talk/Week-of-Mon-20091102/015596.html
Oh boy, am I interested in this shit. If the developing brain and its later operation `adapt' to its greater context of human relationships, society and its orders, and the physical world over its lifetime, do you see the potential for a vast sort of `relativism'? This implies more than a theory of learning.
On the other hand I could argue for constants. Let's start here:
``...environment or niche to which an organism must adapt is not arranged according to logic...''
It depends on which features of the environment we consider.
Let's consider space. Space is universally ordered by gravity. It's down vector presents our space with a distinct ordering principle we recognize as the euclidean symmetries of motion: up, down, right, left, forward and backward. (Or in terms of navigation, the compass points). These are constants for the brain frame of reference. The bilateral symmetries of many different kinds of animals are a physical evolutionary mapping onto the physics of these symmetries and their forces.
This set of symmetries has a logic that can be seen in what's called the group algebra. It doesn't matter too much what that means. The point is that there is usually a form of logic or algebra imparted to the environment through the physical features of the world.
Here is a passage I was reading several months ago, from ``Mind as Motion, Explorations in the dynamics of cognition''. This is a fascinating book, but I haven't read through it. Just picked up bits and pieces.
``...Piaget believed that human cognition was a biological adaptation designed to know the truths about the world by logical structures. He wanted to understand how people acquired and perfected these logical structures during development. Piaget made several assumptions that may be challenged by a dynamic cognition---first, that there are logical relations in the world to be discovered, and second, that people symbolically represent these relations in mind through a series of propositional structures.'' (Esther Thelen, 3.4 The Piagetian Legacy, p72)
I think I just showed there are spatial ordering relations in the world and physics spends most of its time trying to discover and articulate them. The reason Piaget was so interested in the child development especially the neuromuscular system was because he started off in math and physics and at first imagined him self as a philosopher of science. Instead he chose to be a scientist in developmental psychology.
In any event, Piaget's mistake (I think) was he took up a Cartiesan position in his approach, looking for ordering principles within the mind. If you think about this, you realize the brain doesn't need to possess some group algebraic structure, because that already exists in the world. All the brain via experience as to do is have adaptive systems (including learning) that entrain on key ordering features of the world. These environmental features will map onto and in, and help organize brain development as well as thinking and action.
Then onto the second point about the symbolic representations of ordering systems of the world what Thelen called propositional structures. I agree about the problem of a linguistically understood concept of propositional structures. However language isn't the only means of symbolic representation and understanding. For example there are the arts. Here we can find many of those space symmetries adapted to many of the abstract patterns that are found through out the world in many different cultures in many different times and places. (I was also thinking about the construction of stone tools, even the simple ones.)
On the other hand, taking the relativistic side. It seems to me, if we take Edelman's view of the brain as an adaptive system, it seems to follow that the controversial linguistic relativity, or Sapir-Whorf hypothesis could be also be true in some form or other. The more fixed structural elements can co-exist with the more relativistic elements. They are not mutually exclusive.
>From my pretend scientist pov, this potential relativistic feature of
languages and mind, is exactly why I think some of the cognition science
crew have to get off their fascination with language and logic. Beyond
problems with relativistic features, there is the problem of the
Cartesian position the focus on language and mind tend to fall into
without noticing. This is also known as the dualism of mind/body
problem. I certainly agree with Searle on the idea of an embodied
cognition.
There are related philosophical and scientific problems. Take the psychology of perception. If you focus on the subject and its experience and try to find some ordering principle within, then you miss the highly ordered external environment. You have to use a kind of dialectical approach. And I think you start down at the bottom tiers of the brain like what's called the hypothalamus-thalamus region. These regions are also associated with `consciousness' per se. This is where you might be able to find something like the Piaget's concepts of `structure' or what I sketched about as something like a group algebra of the symmetries of space-motions.
For example this H-T location is physically where there is likely to be the least amount of motion---while in motion---much like a moving inertial frame gyroscope. If you watch one of those lion chase scenes on Nature, you will notice that the lions hold their heads, with their eye reflex as fixed as possible on the co-moving target, while their body twists, turns, and their hind legs switch back and forth sideways to make up the next switch in direction the prey takes to dodge being captured. Part of the prey evasion of capture are reflexes and reactions and learned behavior that attempt to defeat this system of motions of the predator.
All of this is learned and `instinct' working together.
>From there, maybe it's possible to `build' a conceptual model of mind
and how it works.
CG