Chapter 1: Knowledge
We saw in the introduction that philosophical inquiry
is the result of our ability to reflect on ourselves and
pose questions about the relation between
ourselves and the world.
One of the things that triggers such reflection is
error. When we make mistakes, we can learn to fix
those mistakes, or at least avoid them in the future,
by asking: What did I do wrong?
This question is inherently an act of self reflection.
It requires you to think about yourself, as well as
what you were thinking and why.
Consider an example: You meet someone named
Liza who seems to like you a lot and who is also
very charming and cool. You start hanging out
together, go to a few parties, and within a few
weeks you are thinking about becoming
roommates. One day Liza borrows your car, goes
joyriding with people you don’t even know, and
ends up totaling it. She has no insurance, makes
no attempt to compensate you in any way, and from
that day on goes around telling everyone what a
bitch you are.
An experience like that would really shake you up.
Among other things it will make you ask: How
could I have been such a fool? Why wasn’t I able
to see Liza for the kind of person she obviously is?
If you are a normal sort of person you will figure out
a way to learn something from that experience.
You may learn not to be so easily flattered, or to put
so much stock in superficial characteristics, or to
trust people who you have not known very long or
who have never done anything to earn that trust.
You might also pose a question like this: What can
I do to be absolutely certain that no one ever takes
advantage of me like that again?
Now, as you probably realize, this is a foolish over
reaction. For the only way to make absolutely
certain that no one will ever take advantage of you
again is to be sure that you never have anything to
do with anyone who could possibly do you any
harm. In other words you would need to withdraw
from society completely, and reject even those who
have been close to you all your life, since there is
really no telling for sure when they will turn on you.
The point of this example is that error can lead us
to reflect constructively or destructively.
Constructive self-reflection can help us learn from
experience. Destructive self-reflection can makes
us paranoid.
Descartes’
“If you would be a real seeker after truth, it is
necessary that at least once in your life you doubt,
as far as possible, all things.”
Descartes lived during the infancy of modern
science. Copernicus, Kepler, Galileo (and Newton
soon) had pioneered a way of inquiring into the
world that was producing amazing results. But it
was a way that brought a huge amount of anxiety
from a traditional point of view.
The sources of this anxiety were:
(1) The method was entirely mechanistic.
(2) The method was largely based on probabilities,
and could never promise complete certainty.
Descartes was a mathematician, and the
mathematics with which he was most intimately
acquainted did not in any way satisfy itself with
mechanism or probabilities. Mathematics, for
Descartes was a way of seeing into the very soul of
the universe, and it’s results were absolutely
certain. The model of inquiry being developed by
the physicists and astronomers could promise none
of this.
A less flattering way of thinking about this is to
realize that from a pure philosophical, logical,
mathematical point of view physical science is just
grubby. You actually have to touch things. That’s
just not how we come to know. We come to know
by thought, pure thought, and thought alone.
The Meditations
 The Evil Demon and the method of doubt
 Cogito Ergo Sum and the primacy of the mind.
 Senses vs. Intellect
Blackburn’s Critique
 Examination of method of doubt
o Reconstruction of the argument p22-23
 I have been deceived in the past,
therefore it is possible that I have
always been deceived.
o Is the argument coherent? p23-24
 If you know that you have been
deceived in the past, then you can’t
always have been deceived.
 Can Descartes really succeed in
doubting as much as he wants
to?
 What sort of ‘I’ am I?
o Mental vs. physical p30
 The Cogito establish existence of a
mental I, not a physical one.
o Is the existence of a thinking thing
demonstrated or merely assumed?
 Lichtenberg claims that Descartes
merely assumes his existence as a
thinking thing, but is not entitled to it
by his method. He’s only entitled to
the premise: Thinking is occurring.
 Clarity and Distinctness
o Descartes’ Mathematical Model of Clarity
o
A + A +B + B = 180
2A + 2B = 180
2(A + B) = 180
A + B = 180/2= 90
o Can we be deceived about our clear and
distinct ideas?
 Yes, both our sensory and our
intellectual CD ideas can be wrong.
 The Trademark Argument (p.34)
o This is Descartes proof of God’s existence,
which he requires to demonstrate that
something exists besides Descartes.
 The Cartesian Circle (p. 37)
o This is a criticism of the reasoning the
Trademark argument is involved in.
1. My belief in God’s existence is based only
on CD ideas.
2. Beliefs based only on CD ideas always
lead to true beliefs.
Therefore my belief that God exists is true.
Both of these premises can be questioned, but
the Cartesian Circle is based on asking for Descartes’
argument for premise 2.
Foundations and Webs
Hume’s Critique
You can’t doubt the principles and beliefs you use to
establish doubts. So Descartes project of universal
isn’t possible.
Rational Foundationalism and Rationalism
Rationalism is the theory of knowledge that says all
knowledge must be based on a foundation of reason.
The ultimate problem with rationalism is that if you
start with truths of reason, you never get out to the
external world. This is the problem of solipsism.
Natural Foundationalism and Empiricism
Empiricism is the theory of knowledge that say that all
knowledge must be based on a foundation of
experience.
 We build our knowledge on a foundation of what
we get from nature.
 This is a practical starting place, not essentially a
logical one.
Anti-Foundationalism (p.44)
The AF believes that there are no foundational
beliefs, and that we can only inspect and repair our
system of beliefs, from within. (Remember the Otto
Metaphor.)
Skepticism (p. 48)
Universal skepticism is doubt that we know anything
at all. Specifically, the universal skeptic doubts that
our beliefs reflect the way the world really is.
One useful way of thinking about the significance of
Descartes’ meditations is this: Descartes showed us
that, while it is possible that the universal skeptic is
right, this does not imply, or even suggest that
universal skepticism is one of the reasonable
alternatives.
Descartes moved us from a time when rational belief
was connected to the need for certainty, to a time
when we recognize that rational belief is possible
even under conditions of uncertainty.