Rene Descartes
Modified: 2023-08-13 (3:01 PM CDST)
-
Descartes wore many hats: he was a soldier, a teacher, a
mathematician, and a philosopher.
- Most of you have already heard of
Descartes, the mathematician, but you may not realize it.
- Descartes
invented what we now call Cartesian coordinates, or the system by
which we can graph mathematical functions in two-or three-dimensional
space.
- So, all of those problems you have been working in algebra are
his fault.
- It is interesting to consider how Descartes came to
develop Cartesian coordinates.
- Descartes was lying on his bed
watching a fly. Slowly, it came to him that he could describe the
fly's position at any instant by just three numbers. Those three
numbers were along the planes of the floor and two adjacent walls,
what we now call the x,y,z coordinate system.
- Most cities today are
laid out in Cartesian fashion, so we give directions as x,y
coordinates easily and without realizing it. When we tell a stranger
to go three blocks down Main Street and then turn right on Jackson
and go 10 blocks, we are using Cartesian coordinates. Interestingly,
suburbs have pretty much abandoned such systems, as anyone who has
been lost in a suburban development can testify.
- Interesting as Cartesian coordinates are, that is not our concern
with Descartes.
- Rather, we are much more interested in Descartes the
philosopher and his solution to the mind-body problem.
- That
philosophical problem wrestles with the question of reality itself.
- We could all probably agree about external aspects of reality. For
example, the room you are in is real and the equipment you are using is real. We can touch them, see them, bite them, and so on. When we
close a book, we all agree that we can no longer see the page. So,
external reality, or the body part of the mind-body problem, is not
really the issue.
- The issue really confronts us when we consider our
internal view of external reality, in other words, how our mind
represents external reality and whether it creates de novo other
aspects of internal reality.
- For example, ask yourself what color a
tennis ball is.
- I will make it a multiple choice question: Is it
yellow, is it green, or is it a yellowish green?
- Now go ask your
friends and acquaintances the same question.
- Guess what? You will
find three answers, because different people see the same physical
object in different ways. (I see them as green, by the way. For
years, I could not understand why the cans were labelled "Yellow
Tennis Balls".
- My wife sees them as yellow, and interestingly, my
first son sees them as green.) There is a physiological explanation;
it has to do with genetic differences in eye pigments. We will
discuss color vision in Chapter 3.
- Back to the mind-body problem, the fact that different people
perceive tennis balls differently shows us that internal realities
vary.
- But the mind-body problem is deeper than that when one begins
to consider the interactions between mind and body.
- Before Descartes,
the problem was fuzzy, convoluted.
- People believed that mental powers
routinely affected the physical world.
- For example, the witch down
the road could kill your chickens by hexing them, so you had to be
nice to her.
- Today, we do not think that way, or do we?
- Consider the
following:
- We carry brides across thresholds,
- we put pine trees on
top of buildings when we finish them,
- and we throw salt over our
shoulders after we spill some.
- But, most of us only pay lip service to such behaviors
- . We
do not really believe that our marriage will last if we carry our
bride across the threshold, or that the building will fall if we do
not top it, or that bad luck will follow if we fail to throw the
salt.
- In the Middle Ages, however, people did believe strongly in those
kinds of interactions between internal and external reality. Further,
they believed that both types of realities were completely and
totally bound together.
- Descartes destroyed that type of thinking by
proposing that mind and body were separable. He said that they
existed separately but that they did interact from time to time. For
that reason, we call Descartes' solution to the mind-body problem
interactionism.
- In many ways, one can argue that interactionism led directly to
the creation of the modern world.
- By separating mind and body,
Descartes made it possible to study the two separately, and that is
exactly what happened.
- The route made possible by studying the body
or external reality, is called mechanism.
- Today, we pay more
attention to the engineer's analysis of a building than we pay to
whether or not a building was topped by a pine tree during its
construction. (FYI, in 2004 Reynolds Hall was topped with a pine tree. They building has yet to collapse :-)
- If the building were to collapse, we would look for the
engineer, not for the person who rigged the pine tree.
- In short,
science and technology have flourished by ignoring, at some level,
the mind half of the mind-body problem.
- The route to internal reality or to the mind has been much more
difficult, and in many ways has not been attempted.
- The study of
internal reality is called phenomenology.
- Psychology has always been
interested in the mind.
- Note that physics and chemistry have no such
interest.
- Chemists need not consider the mental state of electrons
when they formulate their equations, for example.
- Psychologists,
however, do have to consider mental states to some extent, and that
requirement makes psychology more complex, by definition, than either
physics or chemistry
- That complexity also helps explain the relative
state of development of psychology as a field.
- Being more complex,
psychology has lagged behind the "hard sciences ."
- So, today
psychologists are interested in both internal and external reality,
and they owe that interest to Descartes and his interactionist
solution to the mind-body problem.
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