Thoughts on "Origins of human thought"

Phil Nicholls (
Fri, 13 Oct 1995 02:41:53 GMT

The branch of philosophy that concerns itself with the nature of
knowledge is called epistemology. There are really only two basic
questions in epistemology:

1. What do we know?
2. How do we know what we know?

Obviously (unless you are a vitalist) human thought is a product of
evolution and a direct result of changes that have occurred in the
human brain. It makes sense, therefore, to address such questions
as the origin of human thought by looking at changes in the brain that
may be associated with changes in human cognative abilities such as
the development of abstract though.

Now scientifically there are two ways of approaching the study of the
evolution of the brain. One of these is by looking and endocrainal
casts of fossil species (paleoneurology) and the other is to compare
the structure and organization of the brain in living species
(comparative neurology). Each approach has drawbacks because each
makes certain assumptions that may or may not be valid.

Paleoneurology, for example, places more emphasis of brain volume than
on the organization of the brain because most changes in the
organization of the brain cannot be observed in the surface morphology
of the brain. True, some organizational trends are associated with
shifting patterns of sulci and gyri and these can be noted on
endocranial casts but only the large sulci and gyri can be studied and
these mostly reflect very gross changes in brain organization.

Comparative neurology allows us to study size and organization
conclusions about brain evolution drawn from such data must be
attenuated by the fact that living organisms are each a product unique
evolutionary histories. Living insectivores are not the ancestors of
primates or any other modern mammalian group. What we learn about
insectivore brains may not be true for early mammals in general.

Putting aside the limitations of methodology for the moment and
getting back to the point, the best way to study the evolution of
human thought is to understand the evolution of thought in mammals and
in particular in primates.

Harry Jerison put forward some interesting ideas in his book "The
Evolution of the Brain and Intelligence." I would like to summarize
some of these ideas and then see if anyone would like to take a moment
from discussing important things like aquatic apes.

The earliest mammals were nocturnal. This means that the sensory
information most critical to their survival was not visual
information. Most important were what might be called distance sences
such as hearing and olfaction. Nocturnal mammals used information
from these senses to construct a perceptual map of the world around
them and then use this perceptual map as a guide to moving though and
interacting with their world.

The construction and use of perceptual maps also produced a
decoupling of behavior from sensation to some extent, leading to less
stereotypic behaviors and producing more and more flexiblity in the
ability to respond to the perceptual map.

If you want to look for the origins of "abstract though" then I think
this is a good place to begin. Surely perceptual maps are
abstractions of the real world constructed from distance sense data.

Phil Nicholls
"To ask a question you must first know most of the answer"
-Robert Sheckley