Results from Meditation 2
I exist
I am a thinking thing
the mind can be understood
independently of the body
The mind is better and more easily
understood than anything physical
I can know the content of my mind (my
ideas, my conscious states).
Ideas
One important result from Meditation 2 is
that I can know my ideas.
Ideas are mental states that represent
something, they are about something
other than themselves (like a picture)
Descartes does not know if the ideas
represent things truly, but he knows he
has them, and knows what they are about.
What is the cause of our ideas?
Three possibilities:
External cause (tree)
Self-caused (unicorn)
Innate (truth)
Descartes does not yet know which of these
possibilities is true, but he thinks that ideas
need some kind of cause or explanation
Can we prove God exists?
It’s important to prove God’s existence,
because once we have God, we don’t
have to worry about the evil deceiver.
Descartes will use a non-deceiving God to
reply to the skeptical arguments of
Meditation I
But you can’t use God, until you prove
God exists.
Principles about causation
Everything must have a cause
The cause must have as much reality as
the effect
The cause of an idea must have as much
formal reality as is found objectively in the
idea.
Descartes needs this last claim to prove
God’s existence
Formal and objective reality
Formal reality is just reality
But objective reality refers only to ideas.
An ideas objective reality is what the idea
is about, what it represents.
If we think of an idea as like a picture, the
formal reality of an idea is what is pictured,
represented by it.
Descartes thinks that if you have an idea,
the cause of the idea must be as “real” as
whatever the idea represents.
IF this is true, and if I have an idea of God,
then I can prove that God must exist.
How?
The first proof for God’s existence
I have an idea of God (an infinite, perfect
being.
The cause of an idea must have as much
formal reality as objectively contained in
the idea
Only God has as much formal reality as is
contained (represented by) the idea of
God
Therefore God exists.
Is the argument any good?
Is it true that the only way you can get the
idea of God is from God. What other ways
might one construct an idea of God?
The proof is even worse given
Descartes high standards
Remember Descartes says that he will
only accept beliefs that are so certain that
even an extremely powerful demon cannot
deceive him
But if a demon can deceive him about
3+5=7, then that demon can surely also
deceive him about “the cause must have
as much formal reality as is objectively in
the idea”
The Cartesian Circle
After proving God exists, Descartes can
say God is not a deceiver, God created
me, so I can trust my cognitive faculties, at
least those idea that I “clearly and
distinctly perceive”
But he can’t use this principle to justify the
premises of the God argument. He needs
God to prove God. But this is a circle.
Another argument for God
I exist
I require a cause
Therefore God exists
???????
What is going on here?
Causation is not so simple
“For because the entire span of one’s life
can be divided into countless parts, each
one wholly independent of the rest, it does
not follow from the fact that I existed a
short time ago that I must exist now,
unless some cause, as it were, creates me
all over again at this moment, that is to
say, which preserves me” (p.78)
Time and Causation
Descartes thinks each moment of time is
separate from every other moment.
Because they are separate, they cannot
causally interact.
In order to cause my existence, the cause
must be here, with me to cause me to
exist. IF its in the past it does not exist,
and cannot create me
So we need a cause that can be copresent with the effect.
God is outside of time, a divine
projectionist creating the world over and
over again at each instant.
How God helps with skepticism
1. if God is a perfect being, then God is not
a deceiver (deception is an imperfection)
2. If God created me so that I am
systematically deceived, God would be a
deceiver
3. According to (1) this is impossible. So I
can trust my senses, my rational insight.