Consciousness: A journey up the Dennett Tower
Introduction
Most people agree that there was a time when no life existed anywhere on the earth. According to modern science, precursors of life emerged for the first in the form of complex organic molecules that could replicate with high fidelity - resulting in lineages or generations of these.
These organic molecules replicated with very high fidelity - but on rare occasions, errors did occur in the process of replication. Whenever such an error occurred during replication, the this "flaw" would be passed on to all subsequent generations of that lineage. This resulted in many parallel "versions" of lineages (of self-replicating molecules).
Now, some versions of lineages would get terminated abruptly -- when all copies of identical molecules (capable of high fidelity replication) got destroyed in the environment before even one of these could move on to the next generation. Other lineages survived and proceeded to ever newer generations. Variety of molecular lineages too proliferated due to occasional errors in replication - these errors referred to as "mutations".
To cut a long story short -- this process of selective survival of lineages triggered biological evolution, leading up to all the bio-diversity that we see on the earth today.
Evolution of "self"
It is reasonable that the first stirrings of "life" that emerged in the primordial oceans of the earth (by way of self-replicating molecules), did not have a sense of "self". Selective survival of some lineages gave a further survival advantage to those molecules that (accidentally) grew a protective "body" around itself. This must have been a critical moment in evolution. For the first time, there was dualism in nature, an "inside" and an "outside". For the first time, there was "self interest" to preserve the body and its "inside" against the vagaries of the environment "outside". This "outside" also included other organisms (self-replicating molecules with bodies) with similar "self interest" in their own survival and reproduction.
Along with "self-interest" evolved what we may call "behaviour". Organisms that could "behave" in a particular manner had relative selective advantage over others that "behaved" differently. Thus complex behaviour patterns evolved and proliferated in the biological world of diverse living creatures.
Again to cut a long story short, -- this process of selective survival of behaviour patterns triggered the evolution of the brain (that controls behaviour); and of "consciousness".
The Dennett Tower
Daniel Dennett
suggested a four stage model to represent the evolution of consciousness and behaviour. His own words about the model that he proposed:-
"It is an outrageously oversimplified structure, but idealization is the price one should often be willing to pay for synoptic insight"
I summarise Dennett's model in the table below:-
Floors of the Dennett Tower
Examples
Level of Consciousness
Genesis of behavioral strategies
Position
Ground Floor: Darwinian creatures
Amoeba, Insects
Behavior purely genetically determined -- lacks ability to learn new behaviour within the life time of an individual organism
Survivors of field tests in earlier generations;
Superset DC
First Floor: Skinnerian creatures
Mammals (Pavlov's dog)
In additional to genetically determined behaviour, new behaviour can be acquired within the life time through the process of conditioned reflex
The behaviour of individual organisms are not wholly designed at birth. New behaviour can be learnt during field tests within the life time of an individual
SC: Subset of DC
Second Floor: Popperian creatures
Higher mammals
Behaviour no longer limited to those inherited through genes; or those acquired as conditioned reflexes. These creatures evolved the ability to hypothesise about the world -- thus enable to make tentative predictions regarding the outcomes of behaviour options.
New behaviour emerges from the ability to hypothesize about the world, based on memory of past experience. What gets selected or abandoned are hypotheses -- rather than behaviours.
PC: Subset of SC
Third Floor: Gregorian creatures
Man
Behaviour that involves incredible cunning made possible by information about the world that are captured in the form of "capsules" of pre-designed tools and cultural traditions. These include reusable tools and behavioural codes; and more importantly language, books etc
The ability to imitate behaviour of other individuals (some other higher animals too have this ability). Thus behaviour based on the benefits of information gathered not just by our ancestors, but also by our social groups over generations, transmitted non-genetically by a "tradition" of imitation.
GC: Subset of PC
Conclusion
Let me quote Dennett himself on the implications of the above model.
Dennett began a lecture on The Role of Language in Intelligence by asking the following question:-
"We human beings may not be the most admirable species on the planet, or the most likely to survive for another mill
ennium, but we are without any doubt at all the most intelligent. We are also the only species with language. What is the relation between these two obvious facts?"
Having introduced the concept of the "tower" (which I refer above as the Dennett Tower), he said:-
"Anthropologists have long recognized that the advent of tool use accompanied a major increase in intelligence. Our fascination with the discovery that chimpanzees in the wild fish for termites with crudely prepared fishing sticks is not misplaced. This fact takes on further significance when we learn that not all chimpanzees have hit upon this trick; in some chimpanzee "cultures" termites are a present but unexploited food source. This reminds us that tool use is a two-way sign of intelligence; not only does it require intelligence to recognize and maintain a tool (let alone fabricate one), but it confers intelligence on those who are lucky enough to be given the tool. The better designed the tool, the more information is embedded in its fabrication, the more potential intelligence it confers on its user. And among the pre-eminent tools, Gregory reminds us, are what he calls mind-tools: words. What happens to a human or hominid brain when it becomes equipped with words? I have arrived, finally, back at the question with which I began."
He concluded the lecture thus:-
"Our human brains, and only human brains, have been armed by habits and methods, mind-tools and information, drawn from millions of other brains to which we are not genetically related. This, amplified by the deliberate use of generate-and-test in science, puts our minds on a different plane from the minds of our nearest relatives among the animals. This species-specific process of enhancement has become so swift and powerful that a single generation of its design improvements can now dwarf the R-and-D efforts of millions of years of evolution by natural selection. So while we cannot rule out the possibility in principle that our minds will be cognitively closed to some domain or other, no good "naturalistic" reason to believe this can be discovered in our animal origins. On the contrary, a proper application of Darwinian thinking suggests that if we survive our current self-induced environmental crises, our capacity to comprehend will continue to grow by increments that are now incomprehensible to us. "
[All quotes of Dennett from The Role of Language in Intelligence ]
Anand Nair
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