Back to the Philosophy 101 Home Page
Back to Main Lecture Notes Page
Lecture Notes: October 7
Note that page numbers herein refer to the Adam and Tannery page numbers, located in the margins of the text.
Getting Rid of
the Deceiver
Once we have a criterion and a proof of the existence of God, everything else
follows.
We'll need a few of the details
On Error, from
MIV (pp 53-4)
1) God exists and is perfectly good
2) God creates and preserves me
3) My faculty of judgment therefore comes from God
:. My judgments never err
Uh-oh: since the conclusion of this argument is false, either it's invalid, or a premise is false.
Furthermore, consider this additional argument:
1) Deception is a defect
2) God has no defects
3) So God is no deceiver (54)
4) God created and preserves me
So, I am not deceived by God
So, the puzzle here is how to explain the possibility of error, given God as a good creator and preserver.
Descartes' solution
to this puzzle is to distinguish between the will and the understanding.
Our power of willing is infinite (56-7)
Our power of understanding is finite (57)
So we err when we apply our will (and judge) outside our understanding.
To avoid making errors, avoid judging unless you have a clear and distinct understanding.
So, we've eliminated the deceiver. Now we can reclaim the world
Remember, clarity and distinctness, as a criterion for knowledge, is ensured only by the presence of God.
And the deceiver
eliminated knowledge of math and of universals.
By defeating the deceiver, we reclaim that which the deceiver called into doubt
What kinds of
knowledge are clear and distinct? MV (pp 64-5)
Mathematical truths themselves
Mathematical properties of objects (extension, e.g.)
God (ontological proof, pp 65-6)
These are all known by proof, and are not sensory
The sensory is
still in doubt, the dream argument lingers, with the resemblance hypothesis
as an explanation of the source of those errors.
Our knowledge of mathematics remains, even in dreams (pp 70-71)
Blocking the dream
argument
pp 89-90: the connectedness through memory characterizes waking states and distinguishes
them from sleeping states
They can exist,
see p 71, but do they?
Are there physical
objects? pp 79-80
1) I seem to sense objects
2) If I seem to sense objects, while there are none, then God is a deceiver
3) God is no deceiver
:. Physical objects exist
What are these
objects like?
only math properties are clear and distinct (extension!) (p 80)
Sensory properties are in doubt
We never completely
defeat the doubt of illusion.
So what good are the senses, then?
The role of the
senses as natural protection of body (p 81)
This is just the best structure for humans
Far better to be deceived once in a while (pp 83-4; also pp 88-9)
Important metaphysical point: bodies are perceived by the mind alone, and only
have extension as real properties.
the other properties are confused representations!
(Locke and Berkeley
take this up)
Still, doesn't allowing us to err make God deceptive?
He could prevent it, even given all these excuses
But understanding the mind/body distinction blocks this accusation
A) I am a thinking thing (p 78)
1) I have a clear and distinct understanding of my mind, without my body
2) I have a clear and distinct understanding of my body, without my mind
3) Whatever I can clearly and distinctly conceive of as separate, can be separated by God, and so are really distinct
:. My mind is distinct from my body
Does he have a
body?
Unlike the sailor and his ship (p 81)
His essence is as a thinking thing.
Does he need a body? No, he has a C&D understanding of self without it (end
of p78)
Perhaps we live in a Berkeleyan world (to be explained soon!)
But then God would be a deceiver
B) proof of distinctness from divisibility (pp 85-6)
1) whatever 2 things have different properties are different objects
2) mind is indivisible
3) body is divisible
:. the mind is not the body
1) 3 doubts
A) Illusion
B) Dream
C) Demon
2) Rationalism (Innate Ideas)
3) Empiricism
4) skepticism (or scepticism)
5) a priori, or innate, knowledge
6) a posteriori, or empirical, knowledge
7) Clarity and Distinctness as criteria for knowledge
8) resemblance hypothesis
9) ontological proof of god's existence
10) Cause of error (will and understanding)
11) role of senses (at end)
12) Knowledge and nature of physical objects
13) mind/body thesis
Midterm exam on Wednesday, October 16.
Next class after that is on Monday, October 21.
We will discuss both Locke and (the beginnings of) Berkeley, then.