PowerPoint Presentation Credibility

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There's intelligent life on other planets.
Would you accept this claim? Accept the claim as
TRUE Reject the claim as FALSE SUSPEND JUDGMENT
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Credibility

• Who can we believe? SOURCES
• What can we believe? CLAIMS

And how confident can we be in what we believe?
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Assessing Credibility
There is no simple rule for assessing credibility.
Assessing credibility requires judgment.
Judgment depends on background knowledge.
This sort of judgment is basically induction.
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Assessing content of a claim

• Role of personal observation

Focus of attention Preparation to distinguish
features Conditions of observation
Expectations, beliefs, biases
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Assessing content of a claim

• Role of personal observation
• Role of background information

Initial plausibility Novelty and conflict
Extent of background information
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Credibility of a source

• Knowledge
• Ability
• Motivation

Education and experience both matter
Physical and mental factors may both be relevant
Desires and beliefs, including prejudices may
work in various ways
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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Arguing backwards is to reason that because we
  have an argument with a true conclusion, in
  premises must be true. An argument is supposed to
  convince us that its conclusion is true, not that
  its premises are true.

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Example Your friend says, All CEOs of
  computer software companies are rich. Bill Gates
  is a CEO of a computer software company. So Bill
  Gates is rich. Since you know that Bill Gates is
  rich, you decide the argument is good and that
  all CEOs of computer software companies are rich.
• Analysis This is arguing backwards. There are
  lots of CEOs of computer software companies that
  are struggling to make a living. An argument is
  supposed to convince us that its conclusion is
  true, not that its premises are true.

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Appeal to authority

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Appeal to authority
• We saw above that we can often accept a claim
  based on authority. But it is a bad appeal to
  authority to say that we should accept a claim
  because a particular person said it when that
  person is not really an authority on the subject
  or has motive to mislead.

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Appeal to authority
• Example What do you think of the new tax plan
  the President announced?
• It must be good, cause Dan Rather said so.
• Analysis Not everything that Dan Rather says is
  true.

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Appeal to authority
• Mistaking the Person for the Claim

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Appeal to authority
• Mistaking the Person for the Claim
• Mistaking the person for the claim. Youre
  mistaking the person (or group) for the claim if
  you believe that the claim is false because of
  who said it. Its often right to suspend judgment
  on a claim if you dont consider the person whos
  making the claim to be a reputable authority on
  the subject. But saying that the claim is
  actually false because of who said it is a
  mistake in reasoning.

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Appeal to authority
• Mistaking the person for the claim
• Example I dont believe the tax cut will
  benefit the poorest in our society. Thats just
  another lie our senator said.
• Analysis This is mistaking the person for the
  claim. Politicians dont lie all the time.
  Theres no shortcut for reading and reasoning
  about a claim in evaluating whether to accept it.

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Appeal to authority
• Mistaking the person for the claim
• Appeal to common belief

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Appeal to authority
• Mistaking the person for the claim
• Appeal to common belief
• An appeal to common belief is to accept a claim
  as true because a lot of other people believe it.
  Typically, such reasoning is a bad appeal to
  authority.

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Common Mistakes in Evaluating unsupported claims.

• Arguing Backwards
• Appeal to authority
• Mistaking the person for the claim
• Appeal to common belief
• Example You go to England and find that
  everyone there is driving on the left-hand side
  of the road. You conclude that you should, too.
• Analysis This is a good reasoning, since you
  also know that every country allows driving on
  just one side.