“Cogito ergo sum”
Lauren Dobbs
Bio
Descartes was a French born
philosopher from the 1600’s.
 He’s most famous for his “Meditations
on First Philosophy” Which consists of
six different “meditations”
 He originally became a lawyer but
changed into philosophy.

General Philosophy
Descartes’ main belief was that nothing is true if
you don’t exist. Because you exist things are.
His second meditation “Concerning the Nature
of the Human Mind: That It Is Better Known
Than the Body” says that everything we know
comes from our mind because there is no
external world without you. Except later in his
meditations he finds Dualism, which means a
body can exist without a mind and a mind
without a body. He believed that there was
perfection within everyone although no one
was perfect
Body vs. Mind
He believed in two different substances,
thinking (res cogitans) and extended
(res extensa).
 Thinking substances are split into infinite
(God) and finite (the mind)
 There was only one extended
substance, finite, which connects the
physical to our minds.
 There are many different thinking
substances possibly an infinite number

Religious Beliefs

In meditation three Descartes comes to the
conclusion that God does exist.

He believed that the idea of God was innate
(born within us), not factitious (invented from
our imagination), or adventitious (from the
outside world).
Arguments
1. Something can not come from
nothing.
2. The cause of an idea must have at
least as much formal reality as the
idea has objective reality.
3. I have in me an idea of God. This
idea has infinite objective reality.
4. I cannot be the cause of this idea,
since I am not an infinite and perfect
being. I don't have enough formal
reality. Only an infinite and perfect
being could cause such an idea.
5. So God — a being with infinite
objective reality — must exist (and be
the source of my idea of God).
6. An absolutely perfect being is a
good, benevolent being.
7. So God is benevolent...
8. So God would not deceive me, and
would not permit me to error without
giving me a way to correct my errors.

Descartes had two
arguments for why
God exists.
Formal reality is how
much reality
something seems to
have
Objective
reality is how
real things
are.
Argument 2
1. I exist.
2. My existence must have a cause.
3. The only possible ultimate causes are
a) myself
b) my always having existed
c) my parents
d) something less perfect than God
e) God
4. Not a. If I had created myself, I would have made myself perfect.
5. Not b. This does not solve the problem. If I am a dependent being,
I need to be continually sustained by another.
6. Not c. This leads to an infinite regress.
7. Not d. The idea of perfection that exists in me cannot have
originated from a non-perfect being.
8. Therefore, e. God exists.
Descartes vs. Plato
Both Descartes and Plato put reason at
the center of their philosophies.
 Both also believe in God.
 The two differ in their ideas of Utopia.
 The ideas of what is real differ slightly:
Plato’s Allegory of the Cave and
Descartes metal view.

Sense Perception
Descartes viewed sense perception as
unreliable.
 He said we can’t trust them because
what we perceive could be like wax.
 Wax can be solid or liquid, hot or cooled,
and the smells can differ. But just
because those factors change doesn’t
mean it is no longer wax. We need our
mind to tell us this not our senses.

Bibliography
"Meditation II by Rene Descartes." Oregon State
University. Web. 15 Feb. 2011.
<http://oregonstate.edu/instruct/phl302/texts/descartes/me
ditations/Meditation2.html>.
 "SparkNotes: Descartes (1596-1650): Themes,
Arguments, and Ideas." SparkNotes: Today's Most Popular
Study Guides. Web. 15 Feb. 2011.
<http://www.sparknotes.com/philosophy/descartes/themes.
html>.
 Descartes, Rene. "Descartes - Degrees of Reality." Trinity
University | Welcome. Web. 15 Feb. 2011.
<http://www.trinity.edu/cbrown/modern/descartesReality.html>.
 "René Descartes." Wikipedia, the Free Encyclopedia.
Web. 15 Feb. 2011.
<http://en.wikipedia.org/wiki/René_Descartes>.
