HUM 115 Lesson Seven

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Lesson 8

• How Good Is The Evidence?
• Part I

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Reading Reminder

• Make sure you have read chapters 7 and 8 in your
  textbook.
• Refresher
• What is an argument?
• What is a fallacy?
• What is a value?
• What is an assumption?

3

• What is Evidence?
• Explicit information shared by the communicator
  that is used to back up or to justify the
  dependability of a factual claim (truth claim).

4

• Types of arguments use evidence differently
• Prescriptive Arguments
• Evidence supports the reasons that are factual.
• Descriptive Arguments
• Evidence is needed to directly support a
  descriptive conclusion.

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The Need For Evidence

• Factual claims (truth claims) are beliefs about
  the world that someone wishes us to accept.
• When we encounter a factual claim we should ask
• Why should I believe it?
• Does the claim need evidence to support it?
• If yes, how good is the evidence?

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• Some factual claims can be trusted more than
  others.
• Since it is often impossible to establish the
  absolute truth or falsity of a claim
• Ask whether a claim is dependable.
• Can we count on such evidence?
• The greater the quality and quantity of evidence,
  the more we can depend upon the claim.

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• Asking the right questions is important when
  trying to determine the dependability of a
  factual claim.
• Factual claims should always cause us to ask for
  evidence.

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• Asking the right questions to find the evidence
• What is your proof?
• Wheres the evidence?
• Are you sure thats true?
• How do you know thats true?
• Why do you believe that?
• Can you prove it?
• Those with well thought out arguments will not
  mind answering the right questions.

9

• If a person gets defensive/angry when you ask
  the right questions
• It might be that their argument is nothing more
  than opinion.
• Everyone may have their own opinions.
• Opinions are not facts.
• Some opinions are WRONG!

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Locating Factual Claims

• We encounter factual claims as
• Descriptive conclusions.
• Reasons used to support either descriptive or
  prescriptive conclusions.
• Descriptive assumptions.
• Examples A thru C on page 94.

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Sources of Evidence

• How and when do we know that evidence is
  dependable?
• When the factual claim appears to be undisputed
  common knowledge.
• When the factual claim is the conclusion from a
  well-reasoned argument.
• When the claim is adequately supported by solid
  evidence in the same communication or by other
  evidence we know.

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• How do we determine the quality of evidence?
• First ask, What kind of evidence is it?
• Once we have identified the type of evidence we
  are better able to determine if the evidence is
  dependable.

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Examples of Evidence
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Intuition as Evidence

• Intuition
• A process in which we believe we have direct
  insights about something without being able to
  consciously express our reasoning.
• Common sense, gut feeling, or hunch.
• Valuable when backed up by extensive relevant
  experiences and readings.
• As critical thinkers we should ask, Is this
  claim based on any other evidence?
• Problem with Intuition Private and not
  verifiable.
• Be wary of intuition as evidence.

15
Personal Experience and Anecdotes as Evidence

• We often rely on personal experiences because
  they are very vivid in our memories.
• This can be very dangerous because our
  experiences are not broad enough to provide any
  real evidence for a factual claim.
• Relying upon personal experiences as evidence
  often leads to the hasty generalization
  fallacy.

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Personal Experience and Anecdotes as Evidence

• A single experience, or a series of experiences,
  may tell us that such outcomes are possible but
  such experiences do not tell us that those
  outcomes are typical or probable.
• We should always use caution when basing a
  conclusion upon personal evidence and/or
  anecdotes.
• Use caution when you read/hear someone say, I
  know someone who or In my experience, Ive
  found

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Testimonials as Evidence

• Someone tries to persuade you of something by
  using a special kind of appeal to personal
  experience they quote particular persons, cite
  extraordinary events, etc.
• This type of evidence is usually not dependable
  as evidence.
• In most cases we should pay little attention to
  personal testimonials until we find out more
  about the expertise, interests, values, and
  biases that may lay behind them.

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Problems with Testimonials

• Selectivity People carefully select the
  testimony they use based on what they believe or
  what they want to be true.
• Personal interest Many testimonials come from
  people who have something to gain from their
  testimony. We should always ask, Does the person
  providing the testimony have a relationship with
  what he/she is advocating? If so, how will that
  relationship affect his/her testimony?

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Problems with Testimonials

• Omitted information Testimonials rarely provide
  sufficient information about the basis for the
  judgment.
• The Human Factor Testimonials are often provided
  by people who have strong feelings about
  something or someone. However we need to ask
  ourselves if there is any other reason we should
  accept their testimony.

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Appeals to Authority as Evidence

• Authorities are sources that are suppose to know
  more than most of us about a given topic, they
  are experts.
• When authors or speakers appeal to authorities or
  experts, they appeal to people that they believe
  are in a position to have access to certain facts
  and have qualifications for drawing conclusions
  from those facts.
• Appeals to authority can potentially provide
  strong evidence for conclusion.

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Appeals to Authority as Evidence

• Keep in mind that authorities
• Can be wrong.
• Can and do disagree.
• Example Bottom of page 101.

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• Critical Questions
• Why should we believe this authority?
• How much expertise or training does the authority
  have about the subject about which he/she is
  communicating?
• Was/is the authority in a position to have
  especially good access to important information
  about the topic? (Ex Eyewitness or second-hand
  information).

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• Critical Questions
• Is there a good reason to believe that the
  authority or expert is relatively free of
  distorting influences?
• Has the authority developed a reputation for
  frequently making dependable claims?
• Have we been able to rely on this authority in
  the past?

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Group Activity

• Page 106 Passage 3

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Video Evaluating Websites
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End of Lesson