The Problem of Knowledge

The Problem of Knowledge
3 things you believe to be
true—i.e. “I believe that…”
Rank from most certain to
least certain.
What causes you to be more
or less certain?
What new information
would cause you to be less
So when we say “I’m certain
that…” what are we saying?
Does Ludwig have beliefs?
Does Ludwig have
Can Ludwig justify his beliefs?
Can Ludwig have knowledge
of the outside world?
Why doesn’t Ludwig realize he
is just a brain in a vat?
What would the ability to “get
outside” of our minds and
experiences allow us to do?
What is “knowledge?”
What does it mean “to
know?” How is it different
from believing?
How do we come “to
Are there things we cannot
Does Ernest know that Brenda’s birthday is today?
(a) Ernest believes that
Brenda’s birthday is
(b) Brenda’s birthday is
really next week.
(a) Ernest has no
opinion about when
Brenda’s birthday is.
(b) Brenda’s birthday is
(a) Ernest randomly throws a dart at the
calendar while shouting “Brenda,” and the
dart lands on today’s date.
(b) Based on this, Ernest decides that today
is Brenda’s birthday.
(c) Today is, in fact, Brenda’s birthday.
(a) Ernest looks at Brenda’s driver’s license
and notices that today is her birthday.
(b) Ernest has no reason to doubt the
accuracy of Brenda’s driver’s license.
(c) Based on this, Ernest believes today is
Brenda’s birthday.
(d) It is true that today is Brenda’s birthday.
True, Justified Belief
What does it mean to say
that a belief is “true?”
How do we determine
whether or not a belief is
Why must we believe the
truth in order for it to be
The Problem of Knowledge
Can we know?
What can we know?
How do we know?
How do we know
that we know what
we claim to know?
Is sense data the same thing as
the thing itself? Does our sense
data give us reality as it actually
Because everything is constantly
changing, is knowledge simply
Are there things we know
without sense data?
Philosophy of knowledge.
Three questions of epistemology:
The study of knowledge and
• Is it possible to have
knowledge at all?
The study of the implications • Does reason provide us with
and significance of statements knowledge of the world
independently of our
like “I know that….” (i.e.
propositional knowledge)
• Does our knowledge represent
reality as it really is?
Knowledge from Reason vs. Knowledge from Experience
A Priori
A Posteriori
“Prior to”—that is, knowledge that
is justified without appeal to
“Posterior to”—that is, knowledge
that is justified by appeal to
• Definitions and logically
necessary truths.
• Empirical knowledge
(observation, sense data, etc.)
• My brother-in-law in married to
my sibling.
• At night, the air temperature is
cooler than during the day.
• Ink pens are hand-held writing
• CR is located south of Eureka off
HWY 101.
• Either it is raining outside or it is
not raining outside.
• A unicorn lives in my backyard.
What do I think? Page 57
It is impossible to ever truly
know anything, for all we
can ever have are merely
opinions and beliefs.
It is possible to have
objective knowledge of
what reality is like in itself.
Reason vs. Experience
When my reason convinces
me that something must be
true, but my experience tells
me the opposite, I trust my
When my experience
convinces me that
something is the case, but
my reason tells me it is
illogical, I trust my reason.
Blank Slate vs. Hard Wired
When we come into the world
at birth, the mind is like a
blank tablet.
Some ideas are directly
known by the mind and are
not learned from experience:
a. the laws of logic; b. the
basic principles of
mathematics; c. cause/effect;
d. concept of perfection; e.
idea of God; f. moral
Knowledge, Probability, and Certainty
Our knowledge of reality can
never be absolutely certain.
However, if a belief is true and
we have sufficient evidence of
its probability, we have
Through reason, it is possible
to have knowledge about
reality that is absolutely
Is the Problem of Knowledge Really a Problem?
If we are born “blank
slates,” what obligations do
we have to ensure that all
have equal opportunity to
gain knowledge?
If nothing can ever be
known, how can anything
ever be condemned,
celebrated, or
If knowledge about the
nature of reality is primarily
a priori, how should
children be educated?
If certainty is impossible, by
what criteria do we claim
that a belief is justified?
God and Religion
1= I do have knowledge.
2 =Know is possible but I don’t know
the answer.
There is a God.
Supernatural miracles do
not occur.
3=Knowledge is impossible.
There is life after death.
One particular religion in
the true one.
4-6=very confident
10-12=very skeptical
1= I do have knowledge.
2 =Know is possible but I don’t know the
3=Knowledge is impossible.
Science gives us the best
information about reality.
Science can tell us about the
origins of the universe.
Science can tell us about the
origins of human life.
Scientists will one day be able
to explain all human behavior.
4-6=very confident
10-12=very skeptical
Moral Knowledge
1= I do have knowledge.
2 =Know is possible but I don’t know the
3=Knowledge is impossible.
Some actions are objectively
right or wrong.
The convention of one’s
society determine what is
right or wrong.
Pleasure is the only thing in
life that has value.
Sometimes it could be one’s
moral duty to lie.
4-6=very confident
10-12=very skeptical

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