WHERE ARE WE KNOW NOW?
A review of what we have covered in theory of
knowledge so far
IT ALL STARTS WITH DESCARTES…
Descartes’ Project (in the Meditations): To build a system of
knowledge.
I. A Foundational Theory of Knowledge attempts to build a
theory such that :
a. Each of the initial premises must be indubitable (no
one could doubt it) and incorrigible (not subject to
correction).
In other words, each premise must be such that were any
person — any minimally rational and sane person — to
consider that proposition, he or she would agree that the
premise is true.
b. Each step of the argument must follow indubitably
from the previous premise(s). In Descartes’ terms,
we can simply see by The Light of Reason, that each
step must be true given the previous step(s).
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II. Using the method of doubt (discarding every belief that is not
certain) , he arrives at the Cogito “I think, therefore I am” and the
conclusion that the only things of which he is certain are the
contents of his own thoughts—the way things seem to him.
He concludes that he knows the contents of his mind better than
anything else—and this includes innate ideas.
And now I have brought myself back to where I wanted
to be. I now know that physical objects are not really
known through sensation or imagination but are grasped
by the understanding alone. And from the fact that
physical ideas are grasped in virtue of their being
understandable (rather than tangible or visible) I infer
that I can’t know anything more easily and plainly than
my mind. p
III. Starting with the idea of God, and using only premises that
Descartes sees clearly and distinctly to be true, Descartes proves
the existence of God.
Having proved the existence of God, he says:
The whole argument comes down to this: I know that I
could not exist with the my present nature (that is, that
I could not exist with the idea of God in me) unless
there really were a God—the very God of whom I have
an idea, the thing having all of the perfections that I
can’t fully comprehend but an somehow reach with
thought, the thing that clearly cannot be defective.
From this it is obvious that he can’t deceive, for the
natural light reveals that fraud and deception arise
from defect. (p. 123)
Hence, because God is no deceiver, the truth of those things I
believe to be true is assured.
SKEPTICISM IS FALSE.
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For Descartes
Knowledge = Justified, True,
Belief
Justification is NONdefeasible
(i.e. our reasons guarantee truth)
When we have knowledge, we
know that we have knowledge.
We can prove that skepticism is
false.
For Locke..
As an Empiricist, Locke starts with the view that all of our Ideas either come from the
senses or they are derived from sensory ideas — even the concepts of numbers, of
God, or abstract concepts like government, etc.
Following Descartes, he starts with the view that we have access to only the content of
our ideas—thus we have only “Certain Knowledge” of sensory ideas and of what
Locke called “relations between Ideas”. You also have knowledge of mathematical
truths and of the existence of God.
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What about knowledge of the external world?
Locke: We can be reasonably certain that there is an external world for
two reasons:
(a) our perceptions are forced upon us (they occur
involuntarily)—we can’t control the information that comes to us
through our senses
(b) There is a definite pattern to our perceptions of the external
world .
Therefore something must be causing theses perceptions and the simplest
hypothesis is that there is an external world.
But what does this mean for Locke’s theory of knowledge?
Appiah’s Interpretation
Knowledge = Justified True Belief
But justification need not be certain; our
reasons are defeasible.
Consequence: we can have justified, true
beliefs that no one would want to call
them knowledge.
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But what does this mean for Locke’s theory of knowledge?
Appiah’s Interpretation
A Better Locke/Interpretation
Knowledge = Justified True Belief
Knowledge = Justified True Belief
But justification need not be certain; our
reasons are defeasible.
We can have “Certain Knowledge”
about only our Ideas and the relations
between them.
Consequence: we can have justified, true
beliefs that no one would want to call
them knowledge.
For Descartes
Knowledge = Justified, True,
Belief
Justification is NONdefeasible
(i.e. our reasons guarantee truth)
When we have knowledge, we
know that we have knowledge.
We can prove that skepticism is
false.
All other “knowledge” is only “probable
knowledge”: we can know what is
probably true.
For Locke
Knowledge = Justified True Belief
Our reasons must be NONdefeasible.
All Ideas come from the senses.
When we have knowledge, we know that
we have knowledge
We cannot prove that Skepticism is false.
We can know are facts about our Ideas
(which come from the senses) and the
relations between them.
Hence, we cannot have real knowledge
about the physical world, only “probable
knowledge”.
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Verificationism
Skepticism is meaningless! So we don’t have to address it.
Verificationism
Skepticism is meaningless! So we don’t have to address it.
1.
According to the Logical Positivists, in order for a sentence to have meaning
there must be a rule for using that sentence — a rule that tells us when we are
using the sentence correctly and when we are not using the sentence correctly.
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Verificationism
Skepticism is meaningless! So we don’t have to address it.
1.
According to the Logical Positivists, in order for a sentence to have meaning
there must be a rule for using that sentence — a rule that tells us when we are
using the sentence correctly and when we are not using the sentence correctly.
2.
If there were no such rule, we would have no idea how to use the sentence. And
hence it would not be a meaningful sentence.
Verificationism
Skepticism is meaningless! So we don’t have to address it.
1.
According to the Logical Positivists, in order for a sentence to have meaning
there must be a rule for using that sentence — a rule that tells us when we are
using the sentence correctly and when we are not using the sentence correctly.
2.
If there were no such rule, we would have no idea how to use the sentence. And
hence it would not be a meaningful sentence.
NOTE: the logical positivist does not claim that you, yourself, must be capable of
finding out whether any sentence is true or false. Rather, for a sentence to be
meaningful, you must be able to conceive of circumstances that would show
whether the sentence was true or false.
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Take sentences about history. “John Locke was born at Wrington, a village in
Somerset, on August 29, 1632.”
What makes it true?
Obviously you cannot go back in time, say to August 28, 1632, to the village of
Wrington in Somerset, England, and wait to see whether, the next day, John
Locke is born.
But we do know exactly what would make that sentence true, namely, whether or
not, on that day in history, John Locke was or was not born.
So the sentence is meaningful (on the Verificationist Theory of Meaning)
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What about sentences that posit skepticism?
1. There is no physical world beyond you: rather you are a
brain in a vat controlled by the Evil Scientist, Mary.”
What about sentences that posit skepticism?
1. There is no physical world beyond you: rather you are a
brain in a vat controlled by the Evil Scientist, Mary.”
What makes this true is if there is scientist Mary, who is currently feeding your
brain electrical impulses while floating your brain in a vat of cerebral spinal fluid.
Of course, there is no way for YOU to know whether this is true, to somehow
check out the hypothesis. But you can well imagine what would have to be the
case in order for the sentence to be true.
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2) “You may think that you are awake and that there is a
physical world beyond you; in fact, right now you are fast
asleep dreaming and everything you see before you at
present does not exist.”
2) “You may think that you are awake and that there is a
physical world beyond you; in fact, right now you are fast
asleep dreaming and everything you see before you at
present does not exist.”
Of course, as in the case of Evil Scientist Mary, there is no way for you to check
the truth or falsity of this sentence, because even if you seem to wake up right
now, you may still be asleep.
But do you know what would make it true? Yes: If your body lies asleep in bed,
twitching and moaning, and muttering “I’m dreaming! Maybe I’m dreaming!”,
and then eventually you wake up and report the strangest dream, etc. then this
would make the statement true.
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3. “Although you may think you are awake, in fact you have
never been awake. You have always been asleep, merely
dreaming about a physical world that does not exist,
occasionally dreaming that you wake up.”
3. “Although you may think you are awake, in fact you have
never been awake. You have always been asleep, merely
dreaming about a physical world that does not exist,
occasionally dreaming that you wake up.”
This is trickier. If there really is no physical world beyond you, what exactly would
make this sentence true? We can’t imagine you sleeping in bed, because if this
sentence is true, then there is no physical you and no physical bed.
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So has Verificationism shown that skeptical worries are
meaningless?
NO.
It is not clear whether (3) is meaningful or not—that we can talk sensibly about
what it would means to say that we are dreaming ALL THE TIME.
But certainly (1) and (2) seem to be meaningful, even on the Verificationist theory
of meaning.
And we can use either (1) or (2) in order to explain skepticism about the physical
world.
So it does not seem like the Skeptical Thesis is meaningless.
Causal Theories of Knowledge
“Forget REASONS. Justification is about your causal
connections to the world not about what you may know about
it!”
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Thus far there have been two very large problems with any theory of
knowledge.
1) Skepticism About the External World
So far, for everyone, including the Logical Positivists:
Knowledge = Justified, True Belief.
Thus far there have been two very large problems with any theory of
knowledge.
1) Skepticism About the External World
So far, for everyone, including the Logical Positivists:
Knowledge = Justified, True Belief.
Justification is understood in terms of having good reasons to believe that
something is true.
For Descartes (and probably for Locke too), your reasons must guarantee the truth
of the proposition, be indefeasible.
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Thus far there have been two very large problems with any theory of
knowledge.
1) Skepticism About the External World
So far, for everyone, including the Logical Positivists:
Knowledge = Justified, True Belief.
Justification is understood in terms of having good reasons to believe that
something is true.
For Descartes (and probably for Locke too), your reasons must guarantee the truth
of the proposition, be indefeasible.
But you can never have this kind of justification for propositions about the nature
of the external world.
Thus far there have been two very large problems with any theory of
knowledge.
1) Skepticism About the External World
So far, for everyone, including the Logical Positivists:
Knowledge = Justified, True Belief.
Justification is understood in terms of having good reasons to believe that
something is true.
For Descartes (and probably for Locke too), your reasons must guarantee the truth
of the proposition, be indefeasible.
But you can never have this kind of justification for propositions about the nature
of the external world.
So, SKEPTICISM RULES.
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Thus far there have been two very large problems with any theory of
knowledge.
1) Skepticism About the External World
So far, for everyone, including the Logical Positivists:
Knowledge = Justified, True Belief.
Justification is understood in terms of having good reasons to believe that
something is true.
For Descartes (and probably for Locke too), your reasons must guarantee the truth
of the proposition, be indefeasible.
But you can never have this kind of justification for propositions about the nature
of the external world.
So, SKEPTICISM RULES.
2) Gettier Problems
a) You have good reasons for believing that p is true.
b) The statement p is true.
c) But your belief is correct only through blind, dumb, luck.
So we don’t want to say that you KNOW that p is true as the truth of what you
believe depends on sheer good luck.
Example. Knowing that your Blue Honda Fit is in its parking spot.
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2) Gettier Problems
a) You have good reasons for believing that p is true.
b) The statement p is true.
c) But your belief is correct only through blind, dumb, luck.
So we don’t want to say that A KNOWS that p is true.
Example. Knowing that your blue Honda Fit is in its parking spot.
•You leave your blue Honda Fit in parking spot #347 and walk away.
2) Gettier Problems
a) You have good reasons for believing that p is true.
b) The statement p is true.
c) But your belief is correct only through blind, dumb, luck.
So we don’t want to say that A KNOWS that p is true.
Example. Knowing that your blue Honda Fit is in its parking spot.
•You leave your blue Honda Fit in parking spot #347 and walk away.
•You walk by the parking structure at noon, and see a blue Honda Fit in
#347.
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2) Gettier Problems
a) You have good reasons for believing that p is true.
b) The statement p is true.
c) But your belief is correct only through blind, dumb, luck.
So we don’t want to say that A KNOWS that p is true.
Example. Knowing that your blue Honda Fit is in its parking spot at 5 p.m..
•You leave your blue Honda Fit in parking spot #347 and walk away.
•You walk by the parking structure at noon, and see a blue Honda Fit in
#347.
•At 5:00 p.m. when you leave work, you know that your blue Honda Fit is
in its spot and you walk to your car secure in your knowledge (produced by
in your superior epistemic system/powers).
However…
9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She
drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING
zone, and goes in to rob the bank. She leaves the car running outside a 9:32.
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However…
9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She
drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING
zone, and goes in to rob the bank. She leaves the car running outside a 9:32.
9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is
desperate to get to city hall to purchase a Small Business License before they
close for lunch. He hops in and drives away.
However…
9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She
drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING
zone, and goes in to rob the bank. She leaves the car running outside a 9:32.
9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is
desperate to get to city hall to purchase a Small Business License before they
close for lunch. He hops in and drives away.
11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running
late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for
an empty spot. He spys an empty spot and leaves the car there. That spot is
#347.
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However…
9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She
drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING
zone, and goes in to rob the bank. She leaves the car running outside a 9:32.
9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is
desperate to get to city hall to purchase a Small Business License before they
close for lunch. He hops in and drives away.
11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running
late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for
an empty spot. He spys an empty spot and leaves the car there. That spot is
#347.
12:00 NOON. You walk by and see a blue Honda fit in #347.
However…
9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She
drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING
zone, and goes in to rob the bank. She leaves the car running outside a 9:32.
9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is
desperate to get to city hall to purchase a Small Business License before they
close for lunch. He hops in and drives away.
11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running
late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for
an empty spot. He spys an empty spot and leaves the car there. That spot is
#347.
12:00 NOON. You walk by and see a blue Honda fit in #347.
12:30 p.m. The PHIL 100 student leaves his tutorial and drives away in his
blue Honda fit.
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However…
9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She
drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING
zone, and goes in to rob the bank. She leaves the car running outside a 9:32.
9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is
desperate to get to city hall to purchase a Small Business License before they
close for lunch. He hops in and drives away.
11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running
late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for
an empty spot. He spys an empty spot and leaves the car there. That spot is
#347.
12:00 NOON. You walk by and see a blue Honda fit in #347.
12:30 p.m. The PHIL 100 student leaves his tutorial and drives away in his
blue Honda fit.
4:25 p.m. The SFU business student arrives at SFU for his 4:30 class, and
drives desperately around the parking structure. He finds an empty spot. #347.
He parks the car and leaves.
However…
9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She
drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING
zone, and goes in to rob the bank. She leaves the car running outside a 9:32.
9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is
desperate to get to city hall to purchase a Small Business License before they
close for lunch. He hops in and drives away.
11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running
late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for
an empty spot. He spys an empty spot and leaves the car there. That spot is
#347.
12:00 NOON. You walk by and see a blue Honda fit in #347.
12:30 p.m. The PHIL 100 student leaves his tutorial and drives away in his
blue Honda fit.
4:25 p.m. The SFU business student arrives at SFU for his 4:30 class, and
drives desperately around the parking structure. He finds an empty spot. #347.
He parks the car and leaves.
5:00 p.m. You walk to your car secure in the knowledge that your blue Fit is in
#347.
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Normally leaving your car in the parking lot and seeing a car of the
same description in that exact spot 3 hours later, is good evidence
that your car is where you left it.
Normally, you infer that a car that looks exactly like your car and is
parked in the same place IS your car.
But here, the inferences is incorrect.
Hence you do no know that your car is in your parking spot.
In light of this kind of problem (what I’ll call the “dumb
luck” problem) and the general worry of
skepticism…
Some philosophers have wondered whether justification is NOT just a
matter of what reasons a person has or what a person knows, but
how your beliefs connect to the world.
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On a causal account of knowledge:
a.
You must believe that S
b.
S must be true
c.
Your belief in S must be caused in the appropriate way.
In the case of the Blue Fit, your belief that your car was in the parking lot
was caused by you seeing a Blue Honda Fit.
Normally, this would be enough to justify your belief that your car was
sitting in its parking place.
But THAT Honda Fit was not YOUR Honda fit. But your belief was not
caused in the right kind of way.
Thus on the causal account you do NOT know that your car is in the
parking garage.
Things to NOTE about Causal Accounts.
1. Causal accounts called externalist accounts of knowledge because
whether or not a belief counts as knowledge depends upon the way the
world is (its causal relation to your belief) NOT upon your reasons for
believing what you do. That is, it depends upon events that are
EXTERNAL to you.
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Things to NOTE about Causal Accounts
1.
Causal accounts called externalist accounts of knowledge because
whether or not a belief counts as knowledge depends upon the way the
world is (its causal relation to your belief) NOT upon your reasons for
believing what you do. That is, it depends upon events that are
EXTERNAL to you.
2.
Because knowledge depends upon facts that are external to you, you
may not know when you have knowledge and when you do not. You
do NOT know that know (or don’t know) in all cases.
3.
There is no such thing as a foundational causal account of knowledge,
because justification (on this account) does not depend upon what you
know. Thus we do not need Cartesian indubitable axioms from which
to reason.
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