PHIL 440 (FALL 2006)
INSTRUCTOR: WILBURN
SESSION 2 LECTURE NOTES
9/8/06
Remember last session. We looked at Edmund Gettier’s paper “Is Justified
True Belief Knowledge?”
To briefly review, the standard (JTB) account of knowledge analyzes this
relation as justified true belief.
S knows that P iff
1. P is true,
2. S believes that P, and
3. S is justified in believing that P.
Gettier, in addition, imposes two initial assumptions:
(1) Fallibility (It is possible for a person to be justified in believing a
proposition that is in fact false.)
(2) Transitivity of justification (if S is justified in believing P, and P entails
Q, and S deduces Q from P and accepts Q as a result of this deduction, then
S is justified in believing Q)
In response to this definition, Gettier proposes two counter-examples:
CASE 1: Suppose that Smith and Jones have applied for a certain job. And
suppose that Smith has strong evidence for the following conjunctive
proposition:
d.
Jones is the man who will get the job, and Jones has ten coins in his
pocket.
Smith's evidence for (d) might be that the president of the company assured
him that Jones would in the end be selected, and that he, Smith, had counted
the coins in Jones's pocket ten minutes ago. Proposition (d) entails:
e.
The man who will get the job has ten coins in his pocket.
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Let us suppose that Smith sees the entailment from (d) to (e), and accepts (e)
on the grounds of (d), for which he has strong evidence. In this case, Smith
is clearly justified in believing that (e) is true.
But imagine, further, that unknown to Smith, he himself, not Jones, will get
the job. And, also, unknown to Smith, he himself has ten coins in his pocket.
In our example, then, all of the following are true:
(i) (e) is true,
(ii) Smith believes that (e) is true, and
(iii) Smith is justified in believing that (e) is true.
But do we want to say that Smith knows the (e) is true?
CASE #2: Let us suppose that Smith has strong evidence for the following
proposition:
f.
Jones owns a Ford.
Smith's evidence might be that Jones has at all times in the past within
Smith's memory owned a car, and always a Ford, and that Jones has just
offered Smith a ride while driving a Ford. Let us imagine, now, that Smith
has another friend, Brown, of whose whereabouts he is totally ignorant.
Smith selects three place names quite at random and constructs the following
three propositions:
g.
Either Jones owns a Ford, or Brown is in Boston.
h.
Either Jones owns a Ford, or Brown is in Barcelona.
i.
Either Jones owns a Ford, or Brown is in Brest-Litovsk.
Each of these propositions is entailed by (f). Imagine that Smith realizes the
entailment of each of these propositions he has constructed by (f), and
proceeds to accept (g), (h), and (i) on the basis of (f). Smith has correctly
inferred (g), (h), and (i) from a proposition for which be has strong evidence.
Smith is therefore completely justified in believing each of these three
propositions, Smith, of course, has no idea where Brown is.
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But imagine now that two further conditions hold. First Jones does not own
a Ford, but is at present driving a rented car. And secondly, by the sheerest
coincidence, and entirely unknown to Smith, the place mentioned in
proposition (h) happens really to be the place where Brown is.
If these two conditions hold, then even though
(i) (h) is true,
(ii) Smith does believe that (h) is true, and
(iii) Smith is justified in believing that (h) is true.
But, do we want to say that Smith knows that (h) is true?
Moral: Both of these counter-examples seem to show that justified true
belief is not sufficient for knowledge because a person can make a warranted
inference to a belief that happens to be true, even though its truth has
nothing to do with the premises from which it is inferred.
Our common objection was that one cannot reach a true belief which is
accidentally justified by the evidence one has at hand. We don’t want to say
that one knows if one reasons to a conclusion which, as it were, just happens
to be true in so far as one’s evidence goes.
What options do we have:
(1) We can give supplement the JTB account with extra conditions which
will, along with the truth and belief, collectively insure knowledge.
(2) We can give up the justification condition and try to replace it with some
other condition which will, along with the truth and belief, collectively
insure knowledge.
(3) We can give up one or both of Gettier’s initial assumptions, i.e. fallibility
and transitivity of justification.
In this class session we will concern ourselves with option (1).
First, though, why think that the Gettier examples are important at all?
Consider Earl Conee’s piece, “Why Solve the Gettier Problem?” Conee
argues the following:
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(1) Discovering an analysis of factual knowledge turns on solving the Gettier
problem.
(2) Discovering an analysis of factual knowledge is philosophically
important.
(3) Thus, something philosophically important turns on solving the Gettier
problem.
Conee considers two positions offered against this argument:
Michael Williams:
(1) Which of the two premises is he arguing against, and why?
(2) What challenge does he think that knowledge theory is ultimately
concerned to address?
(3) Why, on Williams’ account, don’t efforts to address the Gettier challenge
address this question?
Mark Kaplan:
(1) Which of the two premises is he arguing against, and why?
(2) What challenge does he think that (classical Platonic) knowledge theory
is ultimately concerned to address?
(3) Why, on Kaplan’s account, don’t efforts to address the Gettier challenge
address this question?
How does Conee respond to these charges?
Let’s return to option (1) for dealing with the Gettier problem. To repeat,
this is the option of supplement the JTB account with extra conditions which
will, along with the truth and belief, collectively insure knowledge.
One such attempt has been called the “no false lemmas” principle. As
Feldman notes, this principle is suggested by D.M. Armstrong in the
following passage:
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“This simple consideration seems to make redundant the
ingenious argument of . . . Gettier’s . . article . . . Gettier
produces counter-examples to the thesis that justified true belief
is knowledge by producing true beliefs based on justifiably
believed grounds . . . , but where these grounds are in fact false.
But because possession of such grounds could not constitute
possession of knowledge, I should have thought that they are
too weak to serve as suitable grounds.”
What is the suggestion here? How would Armstrong supplement the JTB
account so as to de-Gettierize it?
S knows that P iff
1.
2.
3.
4.
P is true,
S believes that P, and
S is justified in believing that P.
S’s belief that P is not based on any false assumptions.
What is Feldman’s response to this fourth condition? Does he think that 1-4
collectively guarantee knowledge? Why or why not? What is his own
counter-counter example?
Feldman's case works like this:
You see Nogot waxing a Ford, humming Ford ad jingles to himself, and so
on. On that basis, you conclude that someone in your office is waxing a
Ford, humming Ford ad jingles, and so on. This belief is true. On the basis
of that belief, you conclude that someone in your office owns a Ford. As
before, Haveit owns a Ford so this belief is true.
Once again it seems like you have a justified true belief that someone owns a
Ford, which fails to count as knowledge. In this case it does not look like
your reasoning proceeded through any false steps.
Or, there are other cases which are somewhat more straightforward:
You're in the meadow, and you see a rock which looks to you like a sheep.
So you say to yourself "There's a sheep in the meadow." In fact there is a
sheep in the meadow (behind the rock, where you can't see it).
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Here again you have a justified true belief that there is a sheep in the
meadow, which fails to count as knowledge.
A final example is Goldman’s barn example . . .
In the last two cases, your belief doesn't doesn’t seem to be based on any
reasoning at all, so it is certainly not based on any false lemmas.
A second attempt we will consider to solve the Gettier problem by
supplementing the JTB account with extra conditions is sometimes called
the no-defeater” principle.
The idea here is the following: The problem with the Gettier examples is
forms his belief without reference to additional relevant information “out
there" in the world that would defeat his justification for P.
S knows that P iff
1.
2.
3.
4.
P is true,
S believes that P, and
S is justified in believing that P.
There are no unconsidered premises that defeat the inference to P.
What is Leher’s and Paxson’s response to this fourth condition? Do they
think that 1-4 collectively guarantee knowledge? Why or why not? What is
his own counter-counter example?
Leher and Paxson’s case works like this:
“You see Tom Grabit hide a book underneath his jacket and sneak out
of Widener Library. On the basis of this, you form the justified belief
that Tom stole a library book. As it happens, your belief is true.
However, unbeknownst to you, Tom's mother was going around today
telling people that Tom was thousands of miles away, and that Tom's
evil twin John was visiting Harvard. The fact that Tom's mother said
this is a potentially defeating piece of evidence. If you were to learn of
it, it would defeat your justification for believing that Tom stole the
book. However, as it turns out, it really was Tom who stole the book.
Tom has no twin brother and his mother is a compulsive liar.”
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In this case, the problem is that it seems that you should count be taken to
know that Tom stole the book. The testimony of a compulsive liar, locked up
in an asylum somewhere, which you never hear, should not block your
justified true belief about Tom from counting as knowledge.
So you have to talk about defeaters and defeater-defeaters and defeaterdefeater-defeaters. You can’t take all of this into account unless you are
omniscient. But to require omniscience is just to revoke Gettier’s original
fallibility of justification condition.
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