Knowledge and Reality
Scepticism
Lecture three: Epistemic Contextualism
Ema Sullivan-Bissett
ema.sullivan-bissett@york.ac.uk
www.emasullivan-bissett.com
Feedback and Advice hour: Thursdays, 11:30, office A/101
(weeks 2–6)
A (very brief) recap
The Sceptic’s Challenge
•
The Sceptical Argument
(S1) I do not know that I am not a brain in a vat.
(S2) If I do not know that I am not a brain in a vat then I do not know that I
have two hands.
(SC) I do not know that I have two hands.
•
The Sceptical Paradox
1. I know that I have two hands.
2. I do not know that I’m not a brain in a vat.
3. If I do not know that I’m not a brain in a vat, then I do not know that I
have two hands.
(adapted from Pritchard 2002: 217)
Two Dogmatic Responses
• Perceptual Knowledge (Moore 1959): I know that I
have two hands, and so I know that I’m not a brain in
a vat.
• Perceptual Justification (Pryor 2002): I don’t know that
I have two hands, but absent any defeaters, I have
immediate prima facie justification for believing that I
have two hands on the basis of perceiving that I have
two hands.
Contextualism
Changing Contexts:
Dinner Party Case
•
One seat with little leg room. I ask you whether
Michael is tall. You say he is 6’5”, we agree that:
1. Michael is tall.
(Feldman 1999: 92).
Changing Contexts:
Basketball Case
• After dinner, we discuss whether
Michael could make it as a basketball
player. You say he could only play
centre but players in that position are
typically 7’ tall. We agree that:
2. It is not the case that Michael is tall.
(Feldman 1999: 92).
•
1.
Michael is tall.
2.
It is not the case that Michael is tall.
I was right when I asserted 1, and I was right when I asserted 2:
‘[W]hether the word 'tall' applies to an object depends in part upon
facts about the context of attribution. When someone
predicates 'tall' of something, there is typically a contextually
determined standard for the application of the term. The
person's claim is true if and only if the object designated
meets that standard’
(Feldman 1999: 92).
Changing Contexts for Knowledge
‘What it takes for a knowledge sentence to be true can
vary from context to context; sometimes the standards
are more restrictive, sometimes more liberal. The key
point is that the relation a person must bear to a
proposition in order for it to be correct to say that the
person knows the proposition changes according to
context’
(Feldman 1999: 93).
Changing Standards for Knowledge
• Our standards for knowledge change across contexts.
‘In some contexts, when we use the word ‘know’, we
have low standards of knowledge in mind: standards
that are easy to meet. We will then ascribe knowledge
liberally. In other contexts, our use of the word ‘know’
is guided by more demanding high standards. Meeting
these is very difficult. In such contexts, we will ascribe
knowledge only reluctantly’
(Steup 2005).
An Example
‘Consider: you ask me whether I know when the next train leaves for
the city and I tell you “Yes, two o’ clock.” Imagine that I have I have
derived my information from an impeccable source, such as the latest
timetable, so that it seems clear that I really do know. However, you
explain that you have an appointment that you absolutely cannot miss.
Moreover, it does happen occasionally that repairs to the track require
temporary timetable changes. Have I looked into whether any such
changes have been announced for today? No. So do I really know that
the next train leaves at two? Suddenly, things seem less clear’
[sic] (Williams 2001: 1–2).
Closure
• The Closure Principle: ‘If I know that p, and I know that p entails q,
then I know that q’ (Steup 2005).
• Suppose you’re in the Willow. Your being in the Willow entails your
not being in Bier Keller. If you know both of these things, then you
know that you’re not in Bier Keller.
• Closure and the sceptical argument:
P: I am giving a lecture
Q: I am not a brain-in-a-vat.
• Brain-in-a-vat closure: If I know that I am giving a lecture, and I know
that if I am giving a lecture then I am not a brain in a vat, then I also
know that I’m not a brain in a vat.
• (Notice: denying closure is a way out of scepticism, see Dretske 1970.)
Solving the Paradox
1.
2.
3.
I know that I have two hands.
I do not know that I’m not a brain in a vat.
If I do not know that I’m not a brain in a vat, then I do
not know that I have two hands.
(adapted from Pritchard 2002: 217)
The solution:
•
In ordinary, low standard contexts, 1 and 3 are true, but,
by modus tollens, 2 is false. In sceptical, high standard
contexts, 2 and 3 are true, but, by modus ponens, 1 is
false. The paradox is resolved.
Responding to the Argument
(S1) I do not know that I am not a brain in a vat.
(S2) If I do not know that I am not a brain in a vat then I do not know
that I have two hands.
(SC) I do not know that I have two hands.
• In ordinary, low standard contexts, premise (S1), by modus tollens is
false (since the conclusion is false because we meet the low standards
for knowledge). In sceptical, high standard contexts, premises (S1) and
(S2) are true, and therefore, by modus ponens, so is the conclusion.
The Contextualist Response: In Brief
‘The problem of skepticism lies in the conflict between skepticism and
everyday epistemic attitudes: skeptical reasoning (at its best) is flawless,
compelling, and thus rationally undeniable; but the skeptical conclusion
is absolutely implausible, even ridiculous, from an “ordinary”
perspective. An adequate response to skepticism should explain how
the knowledge claims we make in everyday life can be true, even
though, in some sense, skepticism is correct. Initially, that seems
impossible: if A and B oppose one another, how could we show that A
is correct without denying B? The contextualist response is that,
although A and B appear to oppose one another, they really do not.
Skepticism and “ordinary” knowledge claims belong to different kinds
of epistemic contexts, so that although skepticism is correct relative to
the standards of knowing operative in its own context, it has no bearing
on knowledge claims made in “ordinary” contexts, where different
standards for knowledge operate’
(Daukas 2002: 63–4).
David Lewis’s Contextualism
‘We know a lot’
‘We know a lot. I know what food penguins eat. I know that phones
used to ring, but nowadays squeal, when someone calls up. I
know that Essendon won the 1993 Grand Final. I know that here
is a hand, and here is another’
(Lewis 1996: 549).
‘Besides knowing a lot that is everyday and trite, I myself think that
we know a lot that is interesting and esoteric and controversial.
We know a lot about things unseen: tiny particles and pervasive
fields, not to mention one another’s underwear. Sometimes we
even know what an author meant by his writings’
(Lewis 1996: 549).
‘We know next to nothing’
‘For no sooner do we engage in epistemology […] than we
meet a compelling argument that we know next to nothing.
The sceptical argument is nothing new or fancy. It is just
this: it seems as if knowledge must be by definition
infallible. If you claim that S knows that P, and yet you
grant that S cannot eliminate a certain possibility in which
not-P, it certainly seems as if you have granted that S does
not after all know that P. […] Those possibilities of error
are far-fetched, of course, but possibilities all the same.
They bite into even our most everyday knowledge. We
never have infallible knowledge’
(Lewis 1996: 549).
Knowledge
‘Subject S knows proposition P iff P holds in
every possibility left uneliminated by S’s
evidence; equivalently, iff S’s evidence
eliminates every possibility in which not-P’
(Lewis 1996: 551).
Eliminating Possibilities
• Uneliminated possibilities are the ones in which
the subject’s perceptual experience and memory
are as they are in actuality:
‘[A] possibility W is uneliminated iff the subject’s
perceptual experience and memory in W exactly
match his perceptual experience and memory in
actuality’
(Lewis 1996: 553).
Possibilities and Domains
• Looking around the lecture theatre I say ‘Everyone looks
tired’.
• When I say that I – and my audience – ignore all of the
people in the world that aren’t currently in the lecture
theatre.
• Those people are outside of the
domain to which my claim was
restricted, and so ‘are irrelevant
to the truth of what was said’
(Lewis 1996: 553).
Proper Ignoring
• New definition of knowledge:
‘S knows that P iff S’s evidence eliminates every
possibility in which not-P […] except for those
possibilities which we are properly ignoring’
(Lewis 1996: 554).
• What can be properly ignored?
‘[O]f course, I am not entitled to ignore just any
possibility I please’
(Lewis 1996: 554).
Compare: Flat Surface
‘Just as P is known iff there are no uneliminated
possibilities of error, so likewise a surface is flat iff
there are no bumps on it. We must add the proviso:
Psst! – except for those bumps that we are properly
ignoring. Else we will conclude, absurdly, that
nothing is flat’
(Lewis 1996: 554).
BREAK
(which tell us which possibilities we
cannot properly ignore)
But First: Possible Worlds
Actual
world
ES-B is
giving a
lecture at
15:00 on
21/10/14
(YOU ARE
HERE)
Possible
world
one
ES-B is
giving a
lecture at
16:00 on
21/10/14
Possible
world
two
ES-B is giving
a lecture at
16:00 on
21/10/14
stood on her
head.
ES-B is giving a lecture at 16:00 on
21/10/14 and ES-B is not giving a
lecture at 16:00 on 21/10/14.
Possible
world
three
ES-B is giving a
lecture at 16:00 on
21/10/14 stood on
her head with a live
chicken sticking out
of her nose.
Impossible
world
Rule of Actuality
• ‘The possibility that actually obtains is never
properly ignored’ (Lewis 1996: 554).
• What is actual is always a relevant alternative.
• Whose actuality is important?
‘There is just one actual world, we the ascribers
live in that world, the subject lives there too, so the
subject’s actuality is the same as ours’
(Lewis 1996: 555).
Rule of Actuality and
Other World Knowledge Ascriptions
• I didn’t watch the X-Factor results on Sunday. If I had
watched them I would know which act left the show.
• In the nearby possible world in which ES-B did watch the
X-Factor results on Sunday, ES-B knows which act left the
show.
• The ascriber can ascribe knowledge to the subject that she
(the ascriber) does not possess.
• When the subject of knowledge ascriptions and the
ascriber’s worlds are different, ‘it is the subject’s actuality,
not the ascriber’s, that never can be properly ignored’ (Lewis
1996: 555).
Rule of Belief
• ‘A possibility that the subject believes to obtain is not
properly ignored, whether or not he is right to so believe’
(Lewis 1996: 555).
• If Sally believes that Fred ate the last cookie in the cookie
jar (when it was actually Tim), she cannot know that Tim
ate the last cookie in the cookie jar.
Rule of Belief
cont.
• ‘Neither is one that he ought to believe to obtain – one that
evidence and arguments justify him in believing – whether
or not he does so believe’ (Lewis 1996: 555).
• If Sally knows that Fred is allergic to cookies, and that Tim
is a sucker for cookies (and regularly eats the last one),
Tim’s having eaten the last cookie in the cookie jar is not a
possibility which can be properly ignored when ascribing
knowledge to Sally.
Rule of Resemblance
•
‘Suppose one possibility saliently resembles another. Then if one of them
may not be properly ignored, neither may the other’ (Lewis 1996: 556).
‘Unbeknownst to me, I am travelling in the land of the bogus barns; but my
eye falls on one of the few real ones. I don’t know that I am seeing a barn,
because I may not properly ignore the possibility that I am seeing yet
another of the abundant bogus barns. This possibility saliently resembles
actuality in respect of the abundance of bogus barns, and the scarcity of
real ones, hereabouts’
(Lewis 1996: 557).
BOGUS BARN
BARN
BOGUS BARN
BOGUS BARN
Rules of Method
1.
We can presuppose that a sample is representative.
2.
We can presuppose that the best explanation of our
evidence is the true explanation.
‘[W]e are entitled properly to ignore possible failures
in these two standard methods of non-deductive
inference’
(Lewis 1996: 558).
Rule of Conservatism
• Generally ignored possibilities may be properly
ignored (Lewis 1996: 559).
• If certain possibilities are normally ignored by
those around us, then (though defeasibly), we too
may properly ignore such possibilities.
• ‘We are permitted, defeasibly, to adopt the usual
and mutually expected presuppositions of those
around us’ (Lewis 1996: 559).
Rule of Attention
• What is being properly ignored is a feature of
conversational context. (Lewis 1996: 559).
‘[A] possibility not ignored at all is ipso facto not properly
ignored. What is and what is not being ignored is a feature
of the particular conversational context’
(Lewis 1996: 559).
• In an epistemology seminar, we attend to the possibility
that we are brains in vats, and hence this possibility cannot
be properly ignored (because it isn’t being!) In the context
of an epistemology seminar, we do not know that we have
hands.
Responding to Scepticism
‘The pastime of
epistemology does not
plunge us forevermore into
its special context. We can
still do a lot of proper
ignoring, a lot of knowing,
and a lot of true ascribing of
knowledge to ourselves and
others, the rest of the time’
(Lewis 1996: 559).
Hurrah for Contextualism!
‘The obvious attraction of
contextualism, besides (and
closely related to) the
resolution of sceptical
arguments it purportedly
provides, is that it seems to
have the result that very many
of the knowledge attributions
and denials uttered by speakers
of English are true’
(DeRose 1992: 924).
Objections to Contextualism
know
1. Bizarre Dialogues
‘[C]onversations like the following seem to
be incoherent:
“A: Is that a zebra?
B: Yes, it is a zebra.
A: But can you rule out its being merely a
cleverly painted mule?
B: No, I cannot.
A: So, you admit you didn't know it was a
zebra?
B: No, I did know then that it was a zebra.
But after your question, I no longer
know”’
(Yourgrau 1983: 182–3).
Response to 1.
• Contextualism doesn’t license these dialogues.
• Contextualism is a semantic thesis about knowledge claims,
not about knowledge itself.
• All that contextualism licenses is metalinguistic claims like:
‘I was previously such that an utterance of ‘B knows it is a
zebra’ would have expressed a true proposition, but the
different and more demanding proposition which such an
utterance would now express would not be true’
(De Rose, 2000, section 6, cited in Rysview 2001).
Well, how should I answer the question? If there is no special
reason to think they were painted mules then I certainly
wouldn’t want to admit that I didn’t know they were zebras,
but maybe I’m just being stubborn. Suppose I do admit it…
Aha! The witness has
Yes.
Could
you
rule
outknow
the
ISo,
guess
Iyou
didn’t
know
that
did
really
No,
Iearlier
suppose
not.
So,
you
knew
that
they
Just
answer
the
question!
I
saw
some
there.
contradicted
his
claim.
Is
there
any
reason
to
How
do
you
know?
Yes.
possibility
that
they
were
Do
you
know
that?
that
they
they
were
were
zebras.
zebras?
Were
there
any
were
zebras?
First he
says
that
he
knew;
now
think
that
they
were
only
cleverly
painted
zebras inmules?
the
he says hepainted
didn’t.mules,
Now which
of all is
zoo on April
it, Mr. DeRose?
things? rd
23 ?
Dialogue from DeRose (1992: 925–6).
‘Surely something is amiss in this dialogue; my lawyer
should object. I haven’t contradicted my earlier claim, as
much as it looks as if I have. It would be as if the following
had occurred. While standing in a bright yellow room, I
said, “The room is yellow.” The lawyer then dragged me by
the ear into a room in which all was grey and got me to say,
“This room is grey,” and now he is jumping all over me:
“First, he says, ‘This room is yellow,’ then he says, ‘This
room is grey.’ Which is it?” The contextualist maintains
that something very much like this has happened in my
original dialogue with the lawyer’
(De Rose 1992: 926).
2. Contextualism is Off-Target
•
Contextualism misses its target (if its target is scepticism).
•
Contextualism has is that sceptical knowledge claims like ‘Moore doesn’t
know he has hands’ are true only in contexts with high epistemic standards.
•
But the point scepticism pushes is that we do not satisfy ‘even our ordinary
epistemic standards’ (Rysview 2011).
‘The debate about skepticism is […] not [a] debate in which the quality of
our evidence is agreed to and the debate results from different views about
what the standards for knowledge are. Instead, it is a debate about how
good our evidence is. Understood that way, it is difficult to see the
epistemological significance of decisions about which standards are
associated with the word “knows” in any particular context. Contextualism
is, from this perspective, skepticism neutral, in that it does not address this
part of the issue’
(Feldman 2004: 32).
3. A Disappointing Response
• The contextualist response to scepticism: in ordinary
contexts, claims like ‘Moore knows he has hands’ are true,
in stricter contexts, claims like ‘Moore knows he has hands’
are false. So ‘in ordinary contexts the attributions we make
using the word ‘knows’ are often correct, but in contexts in
which skepticism is at issue […] the sceptics are right’
(Feldman 2001: 62).
3. A Disappointing Response cont.
‘I routinely teach epistemology to undergraduates. One part of the course
concerns arguments for skepticism. I've long thought that there were
flaws in those arguments and that exposing them was an interesting,
though not uncontroversial, project. I thought that going through the
arguments helped to bring out features of the concept of knowledge and
its application. Contextualists hold, however, that the arguments for
skepticism are sound, or at least that their conclusions are true in the
contexts in which they are discussed. So, if the contextualists are right,
I've been wrong about those arguments (or at least their conclusions).
That's disappointing’
(Feldman 2001: 62).
4. Non-Sceptics and
Language Competence
• If contextualism is right, competent speakers of
English will agree with sceptical arguments – they
should acknowledge that, in this context, Moore does
not know that he has hands.
• But:
‘There are intransigent skeptics who deny knowledge
in virtually all contexts. There are those who are
unmoved by skeptical considerations. […] On
contextualist views, they don’t understand the
language’
(Feldman 2001: 77).
Next
• Semantic Externalism
• Seminars:
– Do the reading!
– Come with at least one question per topic.
References
Daukas, Nancy 2002: ‘Skepticism, Contextualism, and the Epistemic “Ordinary”’. The hilosophical Forum. Vol. 33, no. 1, pp. 63–79.
DeRose, Keith 1992: ‘Contextualism and Knowledge Attributions’. Philosophy and Phenomenological Research. Vol. 52, no. 4, pp.
913–29.
De Rose, Keith 2000: ‘Now You Know It, Now You Don’t’. Proceedings of the Twentieth World Congree of Philosophy
(Philosophy Documentation Center). Vol. V, Epistemology, pp. 91 -106.
Dretske, Fred 1970: ‘Epistemic Operators’. The Journal of Philosophy. Vol. 67, No. 24, pp. 1007–1023.
Feldman, Richard 1999: ‘Contextualism and Skepticism’. Noûs. Vol. 13, pp. 91–114.
--------------------------- 2001: ‘Skeptical Problems, Contextualist Solutions’. Philosophical Studies. Vol. 103, No. 1, pp. 61–85.
-------------------------- 2004: ‘Comments on DeRose’s “Single Scoreboard Semantics’. Philosophical Studies. Vol. 119, No. 1/2.,
pp. 23–33.
Lewis, David 1996: ‘Elusive Knowledge’. Australasian Journal of Philosophy. Vol. 74, No. 4, pp. 549–567.
Moore, G. E. (1959) ‘Proof of an External World’, in his Philosophical Papers, London: Allen & Unwin; reprinted in T.
Baldwin (ed), G. E. Moore: Selected Writings (London: Routledge, 1993).
Pritchard, Duncan 2002: ‘Recent Work on Radical Skepticism’, American Philosophical Quarterly . Vol. 39, pp. 215–57.
Pryor, J. (2002), ‘The Skeptic and the Dogmatist’, Nous 34: 517–49.
Rysview, Patrick 2011: ‘Epistemic Contextualism’, Stanford Encyclopaedia of Philosophy, online at
http://plato.stanford.edu/entries/contextualism-epistemology/
Steup, Matthias 2005: ‘Epistemology’, Stanford Encyclopaedia of Philosophy, online at
http://plato.stanford.edu/entries/epistemology
Williams, Michael 2001: ‘Contextualism, Externalism and Epistemic Standards’. Philosophical Studies. Vol. 103, No. 1, pp.
1–23.
Yourgrau, P. 1983: ‘Knowledge and Relevant Alternatives’. Synthese. Vol. 55, pp. 175–190.