Descartes and Buddies
“To be or not to be, that is
the question”
As the world shifts
Contradictions
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Carpe diem
(seize the day)
Momento mori
(remember you
must die)
Based on the
concept that life is
brief
Life is a Theater, therefore,
Shakespeare
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All the world’s a
stage/And all the men
and women merely
players:/They have
their exits and their
entrances;/And one
man in his time plays
many parts. As You
Like It
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Life’s but a walking
shadow, a poor
player/That struts and
frets his hour upon
the stage,/And then is
heard no more; it is a
tale/Told by an idiot,
full of sound and
fury,/Signifying
nothing.” Macbeth
If it isn’t a stage, what is it?
Idealism and materialism
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IDEALISM
Some philosophers
believed that all that
exists is, at bottom,
spiritual in nature
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MATERIALISM
Others believed that
all real things come
from concrete material
substances—particles
of matter (even the
soul starts with
movement of tiny
particles in the brain)
Motion Wins
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Newton applied motion to all changes
on earth and in space: principles of
universal gravitation and the motion
of bodies
Everything was thus governed by the
same unbreakable laws
(mechanisms).
Possible to calculate every natural
change with mathematical precision.
The world as a machine
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If so, then everything that happens
is predetermined (“It’s written in the
stars”)
Bye-bye free will
Everything is a product of
mechanical processes, even our
thoughts and dreams
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He was convinced that knowledge is
attainable only through reason
Can’t trust old information
Can’t trust senses
Can this be Plato again?
Long live the rationalists.
If nothing is “true,” what do you do?
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Come up with the new philosophical
system that will direct the world from
this moment forward.
How about two questions:
What can we know? (certain
knowledge)
What is the relationship between
body and mind?
Skepticism
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Is it true that we know nothing?
Skeptics thought so.
But Descartes thought: If natural
sciences develop a method to
provide exact descriptions of natural
sciences, why can’t philosophy?
The big question: In a mechanistic
view, what’s the relationship
between the body and the soul?
The Soul
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Before the 17th century:
• Soul was “breath of life”
• Pervaded all living creatures
• Soul and spirit meant “breath” or
“breathing”
• Aristotle saw soul everywhere as the
“life principle”—could not be separate
from the body
Big Question:
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If the body is a machine, surely the
soul could not be part of this body
machinery.
WHAT IS THE SOUL, THEN?
Mind / Body
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I decide to lift my
arm
I decide to run for
the bus
I think of
something sad
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The arm lifts itself
My legs start
moving
I start crying
Discourse on Method
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We cannot accept anything as being true
unless we can clearly perceive it
Break down compound problem into as
many single factors as possible
Point of departure comes in simplest idea
of all
Philosophy should go from the simple to
the complex
Ensure new insight with constant vigilance
(mathematical in model)
Doubt everything
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When we dream, we feel that we are
experiencing reality
“When I consider this carefully, I find
not a single property which with
certainty separates the waking state
from the dream…how can you be
certain that your whole life is not a
dream?” Descartes
What else is true?
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Descartes concluded that in his mind
was a clear idea of a perfect entity.
He’d always had this idea, so it
clearly did not come from himself,
since he was imperfect. Therefore,
the idea of a perfect entity must
have originated from that perfect
entity itself: God. God’s existence,
then, was as self evident as his own
thinking.