Knowledge and Mind

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Knowledge and Mind

• Thursday, April 19th

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Testimony Two questions

• 1. What is the nature of testimony?
• 2. Can testimonial beliefs be justified?

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1. The Nature of Testimony

• Elucidate the nature of testimony by asking
  several questions
• Does testimony imply truth? Can you testify
  something if what you say is false?
• Does testimony imply that you believe that what
  you testify is true? Can you testify something if
  you believe that what you say is false (even
  though it might in fact be true)?

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2. The Nature of Testimony

• Does testimony imply the intention to testify?
• John is sitting in his room. In the next room,
  his neighbour Jill is talking to herself again.
  She says I really hate my boyfriend. She did
  not have the intention to communicate this
  information to John. Did she testify that she
  hates her boyfriend?
• Answer no.
• Reason no intention to communicate information.

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3. The Nature of Testimony

• Does testimony imply the intention to testify?
• John is sitting in his room. In the next room,
  his neighbour Jill is talking to her friend Anne.
  She says I really hate my boyfriend. She did
  have the intention to communicate this
  information to Anne. John happens to overhear the
  conversation. Did Jill testifying that she hates
  her boyfriend to John?
• Answer no.
• Reason no intention to communicate information
  to John.

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Justification of testimonial-based beliefs

• Two views
• Reductionism, and
• non-reductionism.

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The Nature of Testimony

• Perhaps difficult to answer because testimony
  is a technical term?

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Reductionism

• For a testimony-based belief to be justified,
  there must be additional evidence to support the
  belief. The testimony all by itself is not
  sufficient to give justification to the belief
  based on that testimony.

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Two versions of reductionism

• Global reductionism in order for testimony-based
  belief B to be justified, the hearer must have
  reasons to think that testimony in general is
  reliable.

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Two problems for global reductionism

• 1. Children would have to wait with accepting
  testimony until they have been able to check for
  a wide-ranging samples of testimony that these
  samples are based on a reliable source.
• 2. Unclear that there is a fact of the matter
  regarding whether testimony is reliable in
  general. There are many different types of
  testimony.

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Local reductionism

• This is the view that in order for a
  testimony-based belief to be justified, the
  subject must only have reasons to think that the
  particular instance of testimony is reliable.

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Counterexample to local reductionism

• Fred has excellent reason to believe that Helen
  is a highly reliable source of information.
  Yesterday, Helen told Fred that Pauline is a
  highly trustworthy person when it comes to
  information regarding wild birds. Pauline told
  Fred that albatrosses, not condors, have the
  largest wingspan among birds. Fred believed her
  testimony. In that case, however, Pauline was
  completely wrong. In fact, Pauline is a very
  incompetent and insincere speaker. (from Lackey
  2006)
• Is Fred justified?
• Intuitively no
• According to local reductionism, however, he is!

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Non-reductionism

• The view that a testimony-based belief can be
  justified even though there is no additional
  evidence.

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Counterexample to non-reductionsim

• Sam is a human being. One day, he walks through
  the forest and sees something drop a book. The
  individuals appearance enables Sam to identify it
  as an alien from another planet. Sam picks up the
  book, notices that it is a diary, and reads the
  tigers have eater some of the inhabitants of
  Earth. This information is correct. (from
  Jennifer Lackey 2006)
• Does Sams testimony-based belief have
  justification?
• Yes, according to non-reductionism.
• No, according to our intuitions. It seems
  irrational for Sam to believe this. It may well
  be that these aliens are always insincere and
  deceptive when trying to testify to others.

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Next week

• Perception

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Tuesday, April 24th 2007

• Perception and Radical Scepticism

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Perception

• One of the most important sources of knowledge.
• Testimony even presupposes perception.

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The problem

• The way things look isnt always the way things
  are.
• Example a straight stick will look bend when
  placed underwater.
• Example you look at a red wall. But the wall is
  actually white but illuminated by a red light.
• So is perception a reliable guide to the nature
  of reality? Should we trust perception?

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Radical scepticism and perception

• Suppose you look at your hand. You perceive what
  you think is your hand. And you form the belief
  that you are seeing your hand.
• But do you know that you have hands on the basis
  of perception?
• The sceptic will answer no!

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Radical scepticism

• It might be the case that you are a
  brain-in-a-vat (BIV) or that you are deceived by
  an evil demon.
• The deception is such that it provides you with
  exactly the same experiences as you would have
  had were you not deceived.
• So there is no way to distinguish between being
  deceived into believing that you are perceiving a
  hand, and genuinely believing that you are
  perceiving a hand.

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Evidence underdetermined

• So the problem is that the evidence we have for
  perceptual beliefs is underdetermined. The
  evidence of seeing hands can both be explained by
  us having hands and by our being deceived into
  perceiving hands.

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Sceptical paradox

• All this is formalized in the sceptical paradox
• 1. K BIV
• 2. K BIV ? -K hands
• 3. K hands

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Paradox?

• Because
• (i) intuitive premises
• (ii) sound reasoning
• (iii) counterintuitive conclusion

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Ways out of the paradox

• 1. deny premise 1
• 2. deny premise 2
• 3. accept the conclusion

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Deny premise 1

• Mooreanism.
• We can know that we are not BIVs because we know
  that we have hands
• Reverses the sceptical argument, from modus
  ponens to modus tollens

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• Khands
• Khands --gt K-BIV
• Hence, K-BIV
• Problem dialectially improper response. Also
  does not explain why we think the first premise
  is intuitive.

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Deny second premise

• 2. K BIV ? -K hands
• Underlying this premise is the closure principle
  for knowledge
• If you know that p, and if you know that p
  implies q, then you know that q.
• If you know that you have hands, and if you know
  that having hands implies not being a BIV, then
  you know that you are not a BIV.
• But you dont know that you are not a BIV.
• So you dont know that you have hands.

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Problems

• Closure highly intuitive.
• No explanation of why closure is mistakenly taken
  to be so intuitive.

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Idealism?

• The view that knowledge of the external world is
  not knowledge independent of our perception of
  it, but rather is constituted by our perception.
• The external world is a construct out of our
  appearances.

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Desideratum

• Must explain why we thought the premise so
  intuitive even though it appears false.

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Knowledge and MindThursday April 26th 2007
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Sceptical paradox

• 1. K BIV
• 2. K BIV ? -K hands
• 3. K hands

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Solutions to scepticism

• 1. Mooreanism (deny premise 1)
• 2. Anti-closure (deny premise 2)
• 3. Contextualism

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Anti-closure

• 2. K BIV ? -K hands
• Underlying this premise is the closure principle
  for knowledge
• If you know that p, and if you know that p
  implies q, then you know that q.
• If you know that you have hands, and if you know
  that having hands implies not being a BIV, then
  you know that you are not a BIV.
• But you dont know that you are not a BIV.
• So you dont know that you have hands.

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Problems

• Closure highly intuitive.
• No explanation of why closure is mistakenly taken
  to be so intuitive.

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Contextualism

• Intuition the word knows means the same thing
  in every context of use.
• If we deny this intuition, we might have a way
  out of the sceptical paradox.
• Specifically the word knows means two
  different things either it means knows
  according to high standards, or it means knows
  according to low standards.

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Example Bank Case A

• Suppose that you are driving home with your wife
  on a Friday afternoon. You plan to stop at the
  bank on the way home to deposit your paychecks.
  But driving past the bank, you notice that the
  lines inside are very long. Fortunately, in this
  case it is not important that the checks be
  deposited right away, so you suggest to drive
  straight home and deposit the pay checks on
  Saturday morning. Your wife says, Maybe the bank
  wont be open tomorrow. Lots of banks are closed
  on Saturdays. You reply, No, I know itll be
  open. I was just there two weeks ago on Saturday.
  Its open until noon.

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Example Bank Case B

• Now suppose that everything is as in the previous
  case, besides this youve just written a very
  large and very important check, which will bounce
  when not deposited into your checking account
  before Monday morning.And, of course, the bank is
  not open on Sunday.Your wife reminds you of these
  facts. She then says, Banks do change their
  hours. Do you know the bank will be open
  tomorrow?
• Remaining as confident as you were before that
  the bank will be open then,still,you
  reply,Well,no.Id better go in and make sure.

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Intuitions

• Bank case A knowledge
• Bank case B no knowledge
• Conclusion knows must mean different things in
  different contexts.

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Contextualism

• The truth-conditions of knowledge sentences
  fluctuate with changes in the context.
• So skp might be true in a low-standards
  context, but might be false in a high-standards
  context.

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Versions of contextualism

• 1. Standards for knowledge fluctuate.
• 2. The amount of alternatives you have to
  eliminate fluctuates.

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Contextualism and scepticism

• No knowledge in high-standards contexts.
• Knowledge in low-standard contexts.
• So long as sceptical scenarios are not
  mentioned, we know propositions about the
  external world.

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Alternative explanation for bank cases

• Warranted assertability maneuver 1
• Bank Case A there is knowledge
• Bank Case B there is knowledge, but it would be
  unwarranted to assert that there is knowledge in
  this case.
• We have confused the truth of the knowledge
  sentence with its assertability conditions.

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• Warranted Assertability maneuver 2
• There is no knowledge in Bank Case A, but it is
  warranted to assert that there is
• There is no knowledge in Bank Case B
• We have confused the truth value with the
  conditions for warranted assertion.

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Tuesday, May 1stKnowledge and Mind

• Contextualism and Scepticism
• Sceptical Paradox
• Three solutions to the paradox
• New solution contextualism
• Problem with contextualism

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Practical information

• Exam answer three questions out of 8.
• There will be no division in the exam paper
  between mind and knowledge. You can do
• 3 mind, 0 knowledge
• 0 mind, 3 knowledge
• 2 mind, 1 knowledge
• 1 mind, 2 knowledge

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Sceptical Paradox

• 1. K BIV
• 2. K BIV ? -K hands
• 3. K hands

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Solutions to the sceptical paradox

• 1. Mooreanism (deny premise 1)
• 2. Anti-closure (deny premise 2)
• 3. Scepticism (accept)
• Always explain why the claim you deny or accept
  seemed intuitive but actually is false.

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Problems with these solutions

• All are counterintuitive.
• New solution contextualism. Defended by Keith
  DeRose, Stewart Cohen, David Lewis.

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Contextualism

• Intuition the word knows means the same thing
  in every context of use.
• If we deny this intuition, we might have a way
  out of the sceptical paradox.
• Specifically the word knows means two
  different things either it means knows
  according to high standards, or it means knows
  according to low standards.

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Motivating contextualism The Bank Cases.

• Bank Case A Suppose that you are driving home
  with your wife on a Friday afternoon. You plan to
  stop at the bank on the way home to deposit your
  paychecks. But driving past the bank, you notice
  that the lines inside are very long. Fortunately,
  in this case it is not important that the checks
  be deposited right away, so you suggest to drive
  straight home and deposit the pay checks on
  Saturday morning. Your wife says, Maybe the bank
  wont be open tomorrow. Lots of banks are closed
  on Saturdays. You reply, No, I know itll be
  open. I was just there two weeks ago on Saturday.
  Its open until noon.

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Motivating contextualism The Bank Cases.

• Bank Case B Now suppose that everything is as in
  the previous case, besides this youve just
  written a very large and very important check,
  which will bounce when not deposited into your
  checking account before Monday morning. And, of
  course, the bank is not open on Sunday. Your wife
  reminds you of these facts. She then says, Banks
  do change their hours. Do you know the bank will
  be open tomorrow?
• Remaining as confident as you were before that
  the bank will be open then, still, you reply,
  Well, no. Id better go in and make sure.

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Intuitions

• Bank case A knowledge
• Bank case B no knowledge
• Conclusion knows must mean different things in
  different contexts.

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Contextualism

• The truth-conditions of knowledge sentences
  fluctuate with changes in the context.
• So skp might be true in a low-standards
  context, but might be false in a high-standards
  context.

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Contextualism and scepticism

• No knowledge in high-standards contexts.
• Knowledge in low-standard contexts.
• So long as sceptical scenarios are not
  mentioned, we know propositions about the
  external world.

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Contextualism and Scepticism

• Both the sceptic and the non-sceptic are correct.
  
• 1. K BIV true in a sceptical context, but
  false in a non-sceptical context.
• 2. K BIV ? -K hands
• 3. K hands true in a sceptical context, but
  false in a non-sceptical context

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Problem for contextualism

• Warranted assertability maneuver 1
• Bank Case A there is knowledge
• Bank Case B there is knowledge, but it would be
  unwarranted to assert that there is knowledge in
  this case.
• We have confused the truth of the knowledge
  sentence with its assertability conditions.

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Problem for contextualism

• Warranted Assertability maneuver 2
• There is no knowledge in Bank Case A, but it is
  warranted to assert that there is
• There is no knowledge in Bank Case B
• We have confused the truth value with the
  conditions for warranted assertion.

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Thursday, May 3Contextualism
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Practical matters

• 1. PP slides online
• 2. Check email for C6 and C7

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What is contextualism?

• The truth-conditions of knowledge sentences
  fluctuate with changes in the context.
• So skp might be true in a low-standards
  context, but might be false in a high-standards
  context.

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Contextualism and scepticism

• Both the sceptic and the non-sceptic are correct.
  
• 1. K BIV true in a sceptical context, but
  false in a non-sceptical context.
• 2. K BIV ? -K hands
• 3. K hands true in a sceptical context, but
  false in a non-sceptical context

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Contexts

• 1. Subject contextualism the context of the
  subject determines what the standards for
  knowledge are
• 2. Attributer contextualism the context of the
  attributer of knowledge determines what the
  standards for knowledge are.

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Contexts

• Depending on which error-possibilities are
  mentioned, contexts can involve high standards
  for knowledge or low standards for knowledge.
• If sceptical possibilities are mentioned, the
  standards will move to HIGH.
• If sceptical possibilties are not mentioned, the
  standards will remain at LOW.

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Warranted assertability

• Bank case A intuitive knowledge
• Bank case B intuition no knowledge
• Conclusion either the intuitions about the Bank
  Cases are wrong, or if the intuitions are
  correct knows must mean different things in
  different contexts.

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Warranted assertability

• Warranted assertability maneuver 1
• Bank Case A there is knowledge
• Bank Case B there is knowledge, but it would be
  unwarranted to assert that there is knowledge in
  this case.
• We have confused the truth of the knowledge
  sentence with its assertability conditions.

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Warranted assertability

• Warranted Assertability maneuver 2
• There is no knowledge in Bank Case A, but it is
  warranted to assert that there is
• There is no knowledge in Bank Case B
• We have confused the truth value with the
  conditions for warranted assertion.

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Memory

• Memory is not a mechanism that produces beliefs
  out of nothing.
• Why think that memory is reliable?
• Reductionism about memory we always need
  additional evidence
• Non-reductionism memory all by itself is enough
  to give beliefs based on memory justification.

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Memory

• In fact, the problems for memory-beliefs are
  similar to the problems for testimony-beliefs.

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Next week

• Tuesday some general, overarching, remarks on
  the course.
• Thursday revision meeting. Prepare questions!!