PH1513 Knowledge and Mind

1
(No Transcript)
2
PH1513 Knowledge and Mind

• Tuesday, March 20th 2007

3
PH1513 EpistemologyWeeks 5-12

• 1. Practical matters.
• 2. The link between epistemology and philosophy
  of mind.
• 3. Introduction to epistemology.

4
Practical issues.

• 1. No classes in week 6.
• 2. Essay can be either on philosophy of mind or
  on epistemology.
• 3. Exam questions will be a mix of epistemology
  and philosophy of mind questions.
• 4. Contact details Martijn Blaauw
• Office Old Brewery Ground Floor room
  16.
• Telephone 272798
• E-mail m.blaauw_at_abdn.ac.uk
• 5. Office hours Wed, 11-12, Thurs, 12-1.
• 6. Recording lectures is OK.
• If you have any questions, dont hesitate to
  contact me!

5
Epistemology and Philosophy of Mind

• The connection between these two branches of
  philosophy is the notion of belief.
• To believe something is a mental state as
  such, it is the object of study of philosophy of
  mind.
• To believe something is usually thought to be
  the core ingredient of knowledge.

6
What is epistemology?

• Epistemologists are primarily interested in the
  concept knowledge, but also in related concepts
  like belief, truth, justification for
  belief, and rationality.
• The key question in epistemology is the
  questionWhat is knowledge?
• This question asks what the correct analysis of
  the concept knowledge is.
• This raises two questions

7
Two questions

• I. What type of knowledge do epistemologists
  focus on?
• II. What is conceptual analysis?
• In what follows, I will answer these two
  questions.

8
I. What type of knowledge?

• Four types of knowledge
• (i) Knowledge-how (ability knowledge)
• (ii) Knowledge-wh (interrogative knowledge)
• (iii) Knowledge-Q (direct object knowledge)
• (iv) Knowledge-that (propositional knowledge)
• ? We will focus on (iv) knowledge-that.

9
II. What is conceptual analysis?

• Analysing a concept means providing the
  individually necessary and jointly sufficient
  conditions that must be satisfied in order for
  the concept to be applicable.
• So we try to decompose the concept into its
  consituent parts.
• If any one of the parts is missing, the concept
  cannot be applied.

10
Combining I and II The Key Epistemological
Question

• What is knowledge?
• Where this question should be understood as a
  request to provide a conceptual analysis of
  propositional knowledge (knowledge-that).

11
Examples

• John and Jill are in the kitchen. John reads in
  the newspaper that Hilary Clinton is running for
  president? Does he know that Hilary Clinton is
  running for president?
• Answer Yes.

12
Examples Knowledge implies Belief.

• John and Jill are in the kitchen. John reads in
  the newspaper that Hilary Clinton is running for
  president. John is a very stubborn man, however,
  and does not believe a word of what the newspaper
  (The Sun) says. What the newspaper says is true
  however Hilary Clinton is running for president.
  Does John know that Hilary Clinton is running for
  president?
• Answer No.
• Why not He does not believe it.

13
Examples Knowledge implies Truth.

• John and Jill are in the kitchen. John reads in
  the newspaper that Mel Gibson is running for
  president. John believes that Mel Gibson is
  running for president. The newspaper has it
  wrong, however. Does John know that Mel Gibson is
  running for president?
• Answer No.
• Reason False.

14
Examples Knowledge implies Justification.

• John and Jill are in the kitchen. John reads in
  the newspaper that Hilary Clinton is running for
  president. This is true, and John believes it to
  be true. However, the reporter wanted to play a
  trick on the readers of the newspaper and wanted
  to deceive them by writing that Hilary Clinton is
  running for president the reporter thought this
  was false. Unbeknownst to the reporter, however,
  it is true. Does John know that Hilary Clinton is
  running for president?
• Answer NO
• Reason No justification.

15
The standard analysis of knowledge

• Knowledge
• Justified
• True
• Belief.
• If any one of these is missing, there can be no
  knowledge.

16
Sources of knowledge

• Perception
• Reasoning
• Testimony
• Memory

17
Summary

• What you need to take away from this lecture
• (1) What is conceptual analysis?
• (2) What different types of knowledge can be
  distinguished?
• (3) What is the standard analysis of knowledge?
• (4) What are some standard sources of knowledge?

18
Next week

• Problems for the traditional analysis of
  knowledge in terms of justified true belief.

19
PH1513 Knowledge and Mind

• Lecture 2
• March 1st 2007

20
Structure of the lecture

• 1. Practical issues
• 2. Recap of the last lecture
• 3. Knowledge can not be due to luck
• 4. The value of knowledge

21
Practical issues

• 1. No classes in week 6.
• 2. Essay can be either on philosophy of mind or
  on epistemology.
• 3. Exam questions will be a mix of epistemology
  and philosophy of mind questions.
• 4. Contact details Martijn Blaauw
• Office Old Brewery Ground Floor room
  16.
• Telephone 272798
• E-mail m.blaauw_at_abdn.ac.uk
• 5. Office hours Wed, 11-12, Thurs, 12-1.
• 6. Recording lectures is OK.
• If you have any questions, dont hesitate to
  contact me!

22
Recap of previous lecture

• 1) What is conceptual analysis?
• (2) What different types of knowledge can be
  distinguished?
• (3) What is the standard analysis of knowledge?
• (4) What are some standard sources of knowledge?

23
Sources of knowledge

• Perception
• Reasoning
• Testimony
• Memory
• Special sources sensus divinitatis.

24
Knowledge belief and truth

• Knowledge implies at least belief and truth
• (a) Knowledge implies belief
• John and Jill are in the kitchen. John reads in
  the newspaper that Hilary Clinton is running for
  president. John is a very stubborn man, however,
  and does not believe a word of what the newspaper
  (The Sun) says. What the newspaper says is true
  however Hilary Clinton is running for president.
  Does John know that Hilary Clinton is running for
  president?

25

• (b) Knowledge implies truth
• John and Jill are in the kitchen. John reads in
  the newspaper that Mel Gibson is running for
  president. John believes that Mel Gibson is
  running for president. The newspaper has it
  wrong, however. Does John know that Mel Gibson is
  running for president?

26
Knowledge and luck

• Consider the following case
• Harry forms the belief that the horse Lucky
  Lass will win the next race purely on the basis
  of the fact that the name of the horse appeals to
  him. As it happens, Lucky Lass actually wins the
  race. Did Harry know this?

27
Knowledge and luck

• Intuitively no.
• Reason the fact that Harrys belief is true is a
  matter of sheer luck.
• Compare hitting the bulls-eye by sheer luck
  does not mean you are a skilled archer.

28
Knowledge, luck, and archery

• Knowledge is just like archery in that it is an
  achievement
• Beliefs aim at truth, just like the archer aims
  at the bulls-eye. Hitting the truth (the
  bulls-eye) by luck isnt going to make you a
  skilled archer, nor give you knowledge.

29
Luck and the standard analysis

• One way to characterize the anti-luck condition
  on knowledge would be in terms of justification
  (the third component in the standard analysis of
  knowledge).

30
The value of knowledge

• Why is knowledge valuable?
• First way to answer this question
• Knowledge implies true belief, and true belief is
  instrumentally valuable.
• (It is better to have true beliefs than false
  beliefs, and true belief can serve certain
  purposes).

31
The value of knowledge

• Problems with the first answer
• (1) Some true beliefs are trivial.
• (2) Explaining the value of knowledge in terms of
  the value of true belief implies that knowledge
  is no more valuable than true belief. But we do
  seem to value knowledge more than mere true
  belief.

32
The value of knowledge

• Knowledge is more valuable than true belief
  because knowledge is stable.
• A true belief that also is knowledge is far
  likely to remain fast in response to changing
  circumstances than mere true belief.
• If you know, you could not easily have been
  wrong. If you have mere true belief, you could
  easily have been wrong.

33
The value of knowledge

• Knowledge has intrinsic value it is good of
  itself, regardless of whether the knowledge in
  question serves some sort of purpose. (Knowledge
  is like friendship in this regard we value
  friends not because they are useful to us but
  because they are valuable to us of themselves).
• True belief never is intrinsically valuable but
  only valuable in the instrumental sense.

34
Recap

• Knowledge excludes luck
• True belief is instrumentally valuable
• Knowledge is stable
• Knowledge can be intrinsically valuable

35
Next lecture

• Defining knowledge

36
PH1513 Knowledge and Mind

• Lecture 3
• Tuesday, March 13th 2007

37
Recap

• Lecture 1 some introductory issues
• Lecture 2 knowledge and value
• This lecture Defining Knowledge

38
The problem of the criterion

• Two questions in epistemology
• 1. What is knowledge?
• 2. How much do we know?
• These two questions lead to the following puzzle

39
The problem of the criterion

• We can only answer the first question (What is
  knowledge?) if we already have an answer to the
  second question (What do we know?)
• We can only answer the second question (What do
  we know?), If we already have an answer to the
  first question (What is knowledge?)
• We are trapped in a circle.

40
Solving the problem of the criterion

• First solution methodism you start with an
  answer to the questionWhat is knowledge?
• Second solution particularism you start with an
  answer to the questionWhat do we know?

41
Problem for methodism

• It is mysterious how can we give an account of
  the nature of knowledge without appealing to
  instances of what we think to know?

42
Problem for particularism

• It assumes from the start that scepticism is
  false. But this is not something you can assume,
  it is something you have to argue for. (We will
  return to the problem of scepticism in a later
  lecture).

43
Gettier cases

• The traditional analysis of knowledge
• Knowledge Justified True Belief. This is
  supposed to be an analysis of the concept of
  knowledge in three sufficient and necessary
  conditions.
• Problem for the traditional analysis of
  knowledge Gettier cases. These cases show that
  there is a justified true belief, but no
  knowledge!

44
Example of a Gettier case

• Stopped clock case
• Smith and Jones

45
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.
• 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. Proposition (e) is then true, though
  proposition (d), from which Smith inferred (e),
  is false.
• 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 it is equally
  clear that Smith does not know that (e) is true
  for (e) is true in virtue of the number of coins
  in Smith's pocket, while Smith does not know how
  many coins are in Smith's pocket, and bases his
  belief in (e) on a count of the coins in Jones's
  pocket, whom he falsely believes to be the man
  who will get the job.

46
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.
• 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 Smith does not
  know that (h) is true, 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.

47
Gettier cases the problem

• In all these cases, there is a justified true
  belief. But the belief does not count as
  knowledge nonetheless.
• In the Gettier cases, something true is inferred
  from something false, and one has justification
  for the false proposition.

48
Gettier cases is there a solution?

• Not really.
• Attempts to add a 4th condition (a
  de-Gettierizer) have failed.
• Attempts to replace the justification condition
  with another condition have failed.

49
Back to the problem of the criterion

• Moral to draw there is no straightforward
  analysis of the concept of knowledge and so the
  question What is knowledge? Is hard to answer.
• Problem if knowledge is really such a hard
  concept to analyse, how can it be that we find it
  so easy to determine whether something is a case
  of knowledge or not?

50
PH1513 Knowledge and Mind

• Thursday, March 15th 2007

51
Recap of previous lecture

• Problem of the criterion
• Gettier cases

52
Overview

• I. The elusiveness of knowledge
• II. Justification and Gettier cases
• III. What is justification?
• IV. Four views on the structure of justification

53
The elusiveness of knowledge

• We all apply the concept of knowledge in a very
  skilled way. That is to say we are good at
  determining whether someone knows something in a
  given case and also at determining whether
  someone does not know something in a given case.
• Yet we have so far been unable to give a
  counterexample-free analysis of knowledge in a
  set of necessary and sufficient conditions. For
  every solution to Gettier cases, new
  counterexamples have emerged.
• What does this show?

54
At least three options

• (i) Knowledge is conceptually primitive and
  cannot be analysed at all. The only thing we can
  provide is give a useful gloss of this concept.
  This option questions the assumption that
  knowledge can be analysed in necessary and
  sufficient conditions.
• (ii) Knowledge is a pluralistic concept there
  are multiple analyses of knowledge and they are
  all correct. This option questions the assumption
  that there is only one correct answer to the
  question what is knowledge?
• (iii) Knowledge is to be analysed in one set of
  conditions. But although we think that we are
  skilled in determining whether there is knowledge
  in a given case, we are not as skilled as we
  think we are we often get it wrong.
• (iv) We have not been trying hard enough to find
  the correct analysis of knowledge.
• In what follows, we will play along with option
  (iv).

55
JTB and Gettier Cases.

• Gettier cases show that defining knowledge in
  terms of justified true belief is inadequate.
  There are cases in which a subject has a JTB
  without knowledge.
• Still, most people think that even though JTB is
  not sufficient for knowledge, it still is
  necessary.
• This raises the question what is justification?
  If we want to understand what knowledge is, we
  have ot understand what justification is.

56
Justification

• So what is justification?
• Consider an everyday belief the belief that you
  have two hands. What does it mean to say that
  this belief is justified?
• It could mean that the belief is supported in an
  appropriate way.
• Supported by what? By adequate reasons or grounds.

57
Example

• You believe that you have hands.
• This belief is justified only if it is supported
  by adequate grounds.
• One such ground could be the further belief that
  you are perceiving your hands.
• But now a problem arises how is this latter
  belief justified? For it to be justified it has
  to be based on grounds as well. What are they?

58
The structure of reasons

• We are thus faced with a problem regarding the
  structure of reasons. If justification means that
  beliefs are based on adequate grounds in the form
  of supporting beliefs, then the question arises
  what supports these supporting beliefs?

59
Four options regarding the structure of reasons

• 1. The chain of reasons ends with an unsupported
  belief.
• 2. The chain of reasons ends with a supported
  belief (foundationalism).
• The chain of reasons goes on without an end
  (infinitism).
• The chain of reasons circles back on itself
  (coherentism).

60
Infinitism

• Here the idea is that an infinite chain of
  justification (of supporting grounds) can justify
  beliefs. Most people oppose this view on the
  grounds that it is counterintuitive. But some
  argue (most notably Peter Klein) that besides the
  worry of counterintuitiveness, it is unclear why
  an infinite chain could not justify beliefs.

61
Coherentism

• This is the view that a circular chain of
  justification can justify a belief.
• Support for coherentism tends to cite the fact
  that this is the way in which we usually justify
  our beliefs.
• It can be reasonable to believe something given a
  specific web of beliefs, but unreasonable to
  believe something given another web of beliefs.
• Metaphor a raft

62
Problem for coherentism

• Rick the inflexible mountain climber he has a
  coherent set of beliefs that is completely
  unrelated to reality.

63
Foundationalism

• This is the view that the chain of justification
  ends with a justified belief.
• The end of the chain is a belief that is
  justified in a basic way it does not derive its
  justification from anything else.
• Metaphor pyramid

64
Problem for foundationalism

• It is self-referentially incoherent.
• How to identify which beliefs can serve as
  foundations. Too strict we dont know much. Too
  narrow we know too much.

65
Next week

• More on the structure of knowledge.

66
PH1513 Knowledge and Mind

• Tuesday, March 20th 2007

67
Recap

• Foundationalism
• Coherentism
• Infitinism

68
The use of strange cases in epistemology

• Epistemologists often use very strange and
  improbably cases to argue for particular
  positions, such as last weeks Rick the
  inflexible mountain climber example. How bad is
  this?

69
Strange cases, continued

• One answer not bad at all, so long as the cases
  are at least logically possible.
• Another answer quite bad, since the analysis of
  knowledge one ends up with when taking into
  account all these strange cases will not be
  grounded in the everyday practice of using
  knowledge at all. It is a philosophical
  artefact.

70
Knowledge what is it?

• Knowledge cannot be equal to Justified True
  Belief.
• Replace Justification with something else.

71
Reliabilism

• Knowledge is a cognitive achievement.
• justification is one way of cashing out this
  element, but this was shown to be vulnerable to
  Gettier cases.
• reliabilism is another way of specifying what
  it means to say that knowledge is a cognitive
  achievement. This is not vulnerable to Gettier
  cases. Think back to the stopped clock case no
  knowledge because the clock is not reliable.

72
Reliabilism, continued

• According to reliabilism, knowledge is equal to a
  true belief that results from reliable
  belief-forming mechanisms.
• reliable here refers to the method used which
  must result in more true beliefs than false
  beliefs.
• If your belief was reliably formed, then you have
  genuinely achieved something.

73
A Gettier problem for reliablism

• Thermometer example you look at a broken
  thermometer to determine the temperature in the
  room. The thermometer is broken and it randomly
  fluctuates. The thermometer is also reliable in
  the sense that even though it is broken it
  always gives the correct temperature. The reason
  is that some in the room who is hidden to you is
  adjusting the temperature of the room whenever
  she sees you looking at the thermometer such that
  the room temperature always matches the random
  thermometer readings.
• No knowledge, but still a reliable true belief!
  Also no cognitive achievement since your beliefs
  do not adapt themselves to match the world.
  Rather, the world adapts itself to your beliefs.

74
Virtue Epistemology

• Even though reliabilism faces this
  counterexample, there is something right about
  it. Think back to the archery example a skilled
  archer will hit the target in a wide range of
  different conditionsthis is what it means to be
  a skilled archer being reliable.
• The same goes for the knower, who should not just
  stumble on a true belief, or hit the truth by
  accident, but should hit the truth out of genuine
  skill and, hence, reliability.

75
Virtue Epistemology

• One way to cash out this idea is in terms of
  epistemic virtues or cognitive capacities.
• An epistemic virtue is a character trait that
  makes one better suited to hitting the truth /
  hitting more true beliefs than false beliefs.
• Examples conscientiousness.

76
Virtue Epistemology and the thermometer example

• This way of cashing out reliabilism in terms of
  epistemic virtues can help to solve the
  thermometer example.
• One could now say that the subject does not have
  a reliably formed true belief at all. The reason
  is that the belief is true merely because the
  hidden person interferes.

77
Another problem for reliabilism

• Chicken sexer someone who, by being raised
  around chickens, has developed a highly reliable
  capacity to distinguish male chicks from female
  chicks. Crucially, they tend to have false
  beliefs about the way in which they are
  distinguishing between the sex of the chicks.
• Some intuit that chicken sexers do not know that
  a particular chick is, for instance, male, even
  though the person has a reliably formed true
  belief that results from an epistemic virtue.

78
Internalism / Externalism

• Others intuit that the chicken sexer does know
  that the chick is, for instance two different
  epistemic theories internalism and externalism.

79
Internalism

• In order to know something, one has to be aware
  of the fact that the reasons for the belief are
  good reasons.
• If this is what is required for Knowledge, then
  the chicken sexer does not know.

80
Externalism

• In order to know a proposition, it is not
  necessary that the subject is aware of the
  reasons for the belief being good reasons.
• On this view, the chicken sexer does know.

81
Next lecture

• More on internalism / externalism

82
PH1513

• Thursday, March 22nd 2007

83
Practical

• No lectures in the following three weeks.
• Lectures/tutorials commence in the week of April
  16th.
• Worksheets all in one document online.

84
Recap

• 1. Reliabilism
• 2. Epistemic Virtues
• 3. Internalism / Externalism

85
Internalism versus Externalism

• Two perspectives on what knowledge is
  internalism and externalism
• These perspectives relate either to justification
  (to the condition that has to be added to true
  belief in order to get knowledge) or to
  knowledge
• Knowledge internalism/externalism
• Justification internalism/externalism.

86
Internalism

• According to internalism, the subject must have
  reflective access to the evidence on which her
  belief that p is based, and must, furthermore, be
  able to determine that the evidence is good
  evidence.
• Worry for internalism radical scepticism. The
  demands are very stringent.

87
Externalism

• According to externalism, it is not necessary for
  the subject to be aware of the fact that her
  belief is based on adequate evidence. You can
  know a proposition even if you dont know that it
  is based on good evidence.
• Worry for externalism is this really knowledge?

88
Illustration chicken sexers

• Someone who, by being raised around chickens, has
  developed a highly reliable capacity to
  distinguish male chicks from female chicks.
  Crucially, they tend to have false beliefs about
  the way in which they are distinguishing between
  the sex of the chicks.
• Some intuit that chicken sexers do not know that
  a particular chick is, for instance, male, even
  though the person has a reliably formed true
  belief. The reason is that the subject has no
  reflective access to the evidence on which her
  belief is based.
• Other intuit that chicken sexers do know that a
  particular chick is, for instance, male, even
  though the subject is not able to determine that
  the evidence is good evidence.
• The first answer will be given by persons with
  internalist intuitions.
• The second answer will be given by persons with
  externalist intuitions.

89
Internalism/ExternalismFoundationalism/Coherentis
m

• Four options
• 1. Internalist foundationalism
• 2. Externalist foundationalism
• 3. Internalist coherentism
• 4. Externalist coherentism

90
Motivation for internalism

• Epistemic responsibility
• Epistemic deontology there are epistemic duties.
  
• Examples
• You should not believe falsehoods.
• You should only believe the truth.
• In order for the idea of duties to make sense,
  you should be able to have access to your
  evidence in order to determine whether you should
  indeed believe something. So this seems to imply
  internalism.

91
An argument for deontology

• Maud believes herself to have the power of
  clairvoyance, though she has no reasons for this
  belief. She maintains her belief despite being
  inundated by her embarrassed friends and
  relatives with massive quantities of apparently
  cogent scientific evidence that no such power is
  possible. One day Maud comes to believe, for no
  apparent reason, that the President is in New
  York City, and she maintains this belief, despite
  the lack of any independent evidence, appealing
  to her alleged clairvoyant power. Now in fact the
  President is in New York City, and Maud does,
  under the conditions then satisfied, have
  completely reliable clairvoyant power. Moreover,
  her belief about the President did result from
  the operation of that power. (Bonjour, 1980. p.
  61)

92

• According to BonJour no knowledge.
• Reason no justification, because Maud is
  irresponsible in accepting this belief.
• This suggests a deontological reading of
  justification.

93
A problem for deontology

• If there are duties, we should be able to choose
  what to believe and what not to believe.
  Otherwise, the idea of a duty does not make
  sense.
• It is implausible to say that we can choose what
  to believe. We dont have voluntary control.

94
Direct versus indirect voluntary control

• No direct control.
• There is indirect control over what we believe.

95
Another argument for internalism

• You know that p only if you can justify that p.
  But what it means to justify that p is that you
  are able to give justification for p.
• So the very nature of justification implies that
  this is an internalist notion.
• Problem young children cannot do this but can
  still be justified.

96
After the Spring Break

• Sources of knowledge perception, memory,
  testimony, reasoning.

97
Knowledge and Mind

• Tuesday, April 17th 2007

98
Knowledge and sources of knowledge

• We have discussed what knowledge is (how the
  concept of knowledge should be analyzed).
• We have discussed whether knowledge should be
  analyzed in an internalist or externalist way.
• We have discussed what the structure of knowledge
  is (foundationalism or coherentism).

99
Knowledge and sources of knowledge

• It is now time to discuss where knowledge
  (whatever it is) comes from.
• Some standardly recognized sources are
• Perception,
• Memory,
• Reasoning, and
• Testimony.

100
Sources of knowledge

• Of these sources, perception, testimony, and
  reasoning can produce knowledge.
• Memory, however, can not produce knowledge but
  can only retain knowledge that is already present
  (and was produced by either perception,
  testimony, or reasoning).

101
Relations between different sources

• There are various relations between the sources
  of knowledge.
• No testimony without perception.
• No memory without perception.
• No reasoning without perception (?).
• No perception without memory (?)

102
Testimony

• One of the most important sources of knowledge.
• Much of what we know depends on testimony.
• Two types of question

103
Testimony two questions

• 1. What is testimony?
• 2. How does testimony give justification to a
  belief based on that testimony?

104
1. The Nature of Testimony

• In which cases do we speak of testimony?
• 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)?

105
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?

106
The Nature of Testimony

• Can you testify by manifestation?
• John is sitting in the park. Next to him, a
  middle-aged lady sitts down. She starts singing
  in a very high voice. John forms the belief that
  she is a soprano. Did the middle-aged lady
  testify that she is a soprano?

107
Testimony and Justification

• Two types of answer to the question whether
  testimony-based beliefs can be justified.
• Reductionism
• Non-reductionism

108
Reductionism

• Testimony-based beliefs are not justified in
  virtue of being based on testimony. Their
  justification reduces to something
  non-testimonial, for instance perception.
• There always must be extra, additional, evidence
  for testimony-based beliefs if they are to be
  justified.
• This is associated with the work of David Hume.

109
Non-reductionism

• Beliefs based on testimony can have justification
  just in virtue of being based on testimony.
• No extra, additional, evidence is needed to make
  these beliefs justified.
• This is associated with the work of Thomas Reid.

110
Problems

• For reductionism too strict. Many of our beliefs
  that are based on testimony seem justified to us
  without us being able to give extra evidence.
• For non-reductionism too optimistic. It seems to
  lead to credulism.

111
Next lecture

• More on testimony.