R e n é
D e s c a r t e s
( 1596 - 1650 )
LIFE
He was born in La
Haye France.
He studied
Scholasticism and law at La Fleche - a Jesuit
college.
Descartes invented
analytic geometry.
Did some work in optics
and science.
In 1633 Galileo was
condemned for supporting Copernicus.
Descartes moved to
Holland to avoid condemnation in 1629.
He wanted to support
Galileo's theory of indirect realism.
This theory has a
problem:
Material objects are
perceived indirectly by ideas.
We can never compare
our ideas with physical objects; therefore
We can not know that
our ideas resemble physical objects.
He wanted to persuade
the church to accept modern physics.
Cardinal de Berulle told him it's easier to do it
with Augustine.
AUGUSTINE
Augustine's method
begins with doubt.
The senses cannot
obtain absolute truth.
I doubt, therefore I exist is the only truth that
cannot be doubted.
This truth is certain and eternal.
I cannot be the
author of an eternal truth, for
the effect cannot be
greater than the cause; therefore,
God exists.
In An Historical
Introduction to Philosophical Thinking, Perelman
says:
The idea of literary
property is in fact a modern one; until the time of
the romantics the truth of an idea was more
important than its originality. Novelty was a sign
of error, and therefore no one was afraid of
Plagiarism. On the contrary, it was better to
present a new idea as a form of a very old one, (86).
Descartes became the
tutor to the Queen of Sweden.
He died of pneumonia
in 1650.
CH.
Perelman, Trnaslated by Kenneth A Brown,
An Historical
Introduction to Philosophical Thinking,
Random House, New York.
PHILOSOPHY
1).
The foundation of knowledge is certainty.
Certainty
is what is impossible to doubt.
Check all beliefs by examining their
foundations.
2). We can
doubt our senses.
Distant things,
insanity, dreams,
and memory are unreliable.
(Click
here to learn about memory.)
Wax
Example
3). We can
doubt our inferences.
I could be insane.
There could be an
Evil Demon
deceiving me.
4). But if I
doubt, then I exist.
I think therefore I am; Cogito Ergo Sum is an
inference.
All inferences can be doubted because of #3.
(see above)
I think, I am. This is an identity statement. (I
think = I am.)
This is self evident, clear, and distinct.
5). Only God could cause my concept of God, for
the effect cannot be
greater than the cause; therefore,
God exists.
6). Experiences must be an accurate
representations of reality
since God is no deceiver.
7). Physical
objects are different from minds.
Color, odor, taste, and texture don't
belong to matter.
Extension, movement, shape, and
location belong to matter.
Minds are self-moving, thinking, not extended,
or in a place.
ARGUMENTS
MIND
If I can't think
of something as divided, then it's not
extended.
I can't think of
mind as divided; therefore, mind is not
extended.
or
If I cannot
think of something as divided,
then it's either not an extended thing, or it
is an infinitely extended thing.
Mind cannot be
thought as being divided; therefore, mind is
not an extended thing, or it's an infinitely
extended thing.
Here is what the argument looks like in predicate
logic. Predicate logic is where we argue about the
properties of things:
1. (X) {~Tx >
[ ~Ex V Ix ]}
2.
~Tm / ~Em V Im
You would need to take a
class in logic to understand what you are
seeing. If the abstraction of math is difficult
for you, taking logic would be a good way to get
over that.
THE
WAX EXAMPLE
1. If wax is understood, then
it's understood by our senses
or (imagination or
judgment).
2. Wax is understood.
3. It is not understood by our
senses.
4. It is not understood by our
imagination. / Therefore
5. Wax is understood by our
judgment.
Here is what the argument looks
like in deductive logic:
1. W > [ S V ( I V J ) ]
2. W
3. ~S
4. ~I
/
J
5. S V ( I V J )
1, 2 mp
6. I V J
3, 5 ds
7. J
4, 6 ds
To demonstrate the limitations
of our senses with his wax example. Consider a
piece of wax; your senses detect a color, smell,
taste, texture, sound, and so forth. All these
properties change, when introduced to heat. By
what faculty do we know that this is the same
object? Certainly not the senses. You can
imagine infinite changes. Descartes concludes:
“And so something which I thought I was seeing
with my eyes is in fact grasped solely by the
faculty of judgment which is in my mind."
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