[extropy-chat] About the Evolution of Vision, Cognition and Knowledge
gts_2000 at yahoo.com
Sat Mar 3 01:21:23 UTC 2007
According to traditional (non-evolutionary) empiricists like Locke and
Hume, the mind plays no active role in perception. Instead the objects of
our awareness act on our senses and then the mind steps in to actively
interpret those perceptions. This would seem to be a reasonable view, but
does it conflict with evolution theory? I think so.
Traditional empiricists find themselves in a quagmire when they try to
trace sensory awareness back through the path of evolution. The concept of
sense awareness breaks down at lower organisms, for example at the level
of the microbe.
Primitive animals like the amoeba and the paramecium seem 'aware,' but
what is the nature of this awareness? These animals have no nervous
systems and no obvious sense organs.
One species of paramecia uses a plant (chlorella) to 'see'. The animal
swallows the plant but holds it live as a hostage in its cytoplasm, using
the chemical by-products of its photosynthesis as an 'eye.' The animal
uses the plant to find more light and more food.
Is this a primitive form of vision? If not then why not? After all the
animal is able to detect light and act upon it. Isn't this what we mean by
If by vision we mean something like the ability to experience light then
the answer seems to be no. It is doubtful that amoebas have anything like
what we might call experience of any kind.
A distinction seems necessary here between experience and cognition.
Although amoebas probably have no experience, they do seem capable of a
primitive type of cognition.
Traditional empiricist doctrine holds that knowledge of the world arises
from sense experience. But here we have an organism that seems to acquire
knowledge of its environment separate from any sense experience.
Traditional empiricism seems mistaken here, at least at some levels
outside the realm of human experience.
Cognition seems also to be fundamentally active.
The normal, visually blind paramecium bounces about almost randomly in its
environment in search of food. Although this primitive trial-and-error
searching has no obvious direction, it is nevertheless an active
goal-driven process. This active but random locomotion is, I think, a
primitive method of cognition.
That sense which we call vision is, I believe, an evolutionary descendant
of random locomotion.
Human eyes on this view are analogous to radar towers, active organs that
search the environment and report information back to headquarters. Their
most basic purpose is to save us physical steps. Unlike the blind
paramecium we needn't bounce into walls to know the walls exist.
Also it seems no coincidence that we see only a very narrow band of
electromagnetic radiation. Most objects that reflect electromagnetic
radiation in the visual light band are also impenetrable. That
impenetrability is useful knowledge to any organism. Until very recently
(on the evolutionary time-scale) it was not very useful to know about
Our use of visual light may also have its origin in light-as-food: i.e.,
Probably it is no coincidence that our eyes use the pigment retinol. This
pigment requires nutrition found mainly in plants, or in certain organs of
animals that eat plants. The pigment allows for color vision.
Why do humans need plants to see?
This dependency of humans on plants may be due to a common ancestor of
plants and animals, one that used beta-carotene, a precursor to both human
retinol and plant chlorophyll.
It seems that in our branch of evolution, we lost the ability to eat light
but retained the ability to detect it.
Light detection is perhaps the most basic example of knowledge
acquisition. This knowledge starts with biological knowledge in plants and
animals, but extends to intellectual human knowledge. Vision and all more
advanced forms of cognition can be understood as more efficient
substitutes for primitive trial-and-error random locomotion, including
even the process of forming abstract theories about the world.
All evolution, from the physical and biological to the mental and
cultural, can then be seen as a single contiguous process involving the
growth of knowledge.
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