Descartes Meditation 3

COLLLECT HOMEWORK

I.  (a) How can you know that you know something instead of that you just believe it? (b) What is Descartes' answer; i.e., his 'criterion of knowledge' ? (sec. 35) (c) Give two examples of things Descartes thinks we can know. Give an example of something we can't know for certain. (d) Can you think of a counter-example to Descartes criterion of knowledge?

II. Comprehension check: What's the problem of the two-world view?

III. Descartes 1st Argument for the Existence of God

1.  It is clear from the light of nature that there must be as least as much reality in the cause as in the effect.

• How could the effect get its reality if not from what caused it? 
• How could the cause give that reality if it did not possess it itself?

2. It follows that: 

(a) Something can't come into being from nothing and 

(b) The more perfect (or real) cannot come from the less perfect.

3. This is true of both things in the world and ideas in the mind.

• I cannot have an idea unless it caused by something that has as much reality as the idea

4. Great Chain of Being: Levels of Perfection or Reality. I have an idea of “a substance [God] that is infinite, independent, supremely intelligent and supremely powerful”.

5. The idea could not originate with me because I am finite and the infinite is more real than the finite.

• This comes from premise 2.
• The more real cannot come from what is less real. 
• So, this idea must have been placed in me.

6. Thus, the idea must have been placed in me by a being who is infinite, independent, supremely intelligent and supremely powerful

In other words, from the idea I have of God as a perfect being I can concluded that God must exist. 

IV. Descartes Second Argument for the Existence of God
The Basic Argument
A) i)    Every event must have a cause.
     ii)   This cannot go back indefinitely (infinitely).
     iii)  Thus, there must be a first cause.
     iv)  The first cause must be the cause of itself.
     v)   The source of my own (or anything's) existence isn't either (a) myself, (b) my parents, (c)                    anything less perfect less than God.
     vi)   The first cause is God.

(a)  I could not have created myself (sec. 48). Argument: If he had he would have given himself all the perfections he can imagine. But he has imperfections. So, he must not be God and have the power of self-creation nor be the source of the idea of God. 

(b) I can't self-sustain my existence. Even if I suppose I always existed, something must sustain my existence. However, this can't be true since I have no awareness of any such power within me (sec. 48-49).  Is this true that you can't sustain your own existence as a thinking thing? Does this apply to everything? Is it true that the only evidence you have for capacities are ones you are aware of? Can you think of a capacity you have but that you aren't conscious of?