CREDIBILITY

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Chapter 3

• CREDIBILITY

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We might suspect a claim because

• There is reason to suspect the credibility of the
  claim itself
• There is reason to suspect the credibility of the
  source of the claim

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A Claims Inherent Credibility

• A claim lacks inherent credibility to the extent
  which that claim conflicts with our observations,
  background information, or other credible claims.

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Evaluating a Claims Inherent Credibility

• Does the claim conflict with our observations?
• Does the claim conflict with our background
  knowledge?
• Does the claim have prima facie initial
  plausibility? Is it reasonable at first glance?

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Firsthand Observations

• Firsthand observations are our best sources of
  information, but even these are not infallible
  because
• One may misremember
• Ones observations may have been affected by
  psychological disturbances or intoxication
• Ones observations may have been affected by
  expectations, hopes, fears, etc

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Evaluating a Sources Credibility

• Does the source have sufficient knowledge of the
  subject matter?
• Is the source honest?
• Is the source objective?
• Is the source accurate?

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How to Evaluate a Sources Credibility

• Consider the sources expertise with regards to
  the claims subject matter. Ones expertise may
  be assessed according to his/her education,
  accomplishments, experience, reputation and/or
  occupational position.
• Consider the sources motives in asserting the
  claim.
• Consider whether or not the source has any biases
  concerning the claim.
• Consider any reasons why the source might not be
  accurate.

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Credibility and The News Media

• Things to look out for
• Biases
• Human error
• Government control of the news
• Claims made on talk radio or the internet
• Sensationalism

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Credibility of Advertisements

• Skepticism is typically the best policy
  concerning advertisements. Instead of presenting
  legitimate reasons to purchase a product,
  advertisers often try to
• Elicit certain feelings from their audience
• Depict the product being used or endorsed by
  people whom we like or consider ourselves to be
  like
• Depict the product being used in situations in
  which wed like to find ourselves

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Word of Caution

• Being skeptical of a claim is not the same thing
  as assuming its falsity.
• Second-hand accounts, biased experts, and even
  advertisements may make truthful claims. Just
  because we have reason to doubt their credibility
  doesnt mean that such sources are automatically
  false. In such cases, it is usually best to
  withhold judgment. Only when a claim conflicts
  with our background knowledge should we assume
  that the claim is probably false.

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What is the ad doing?

• The ad depicts a small boy who is sneezing,
  coughing, and apparently miserable. Then a voice
  says, Dont let this happen to your child.
  Prevent colds with Joness Vitamin C Tablets.
• An ad for a new brand of cologne shows a man
  being chased by horde of lustful women.
• An ad with the caption, Get your read On at
  Logans Bookstore, shows Operah Winfrey holding
  a stack of books.

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What is the ad doing? contd

• An attractive, muscular man wearing only a towel
  is shaving. He says, I like to be smooth for my
  lady, so I use Gillette its the best a man can
  get.
• A couple is shown happily frolicking on a beach
  and drinking champagne. Next, a voice says,
  Vacation in Mexico, and experience the time of
  your life!
• The national anthem plays softly while an apple
  pie is displayed against a red, white, and blue
  background. A voice says, Sarah Dees Pies
  Americas Choice

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Probably True, Probably False, or Insufficient
Info for Judgment

• Theyve taught camels how to play poker.
• -- The Daily Bugle
• The femur is a bone in the human leg extending
  from the pelvis to the knee, that is the longest,
  largest, and strongest in the body thighbone.
• -- Medical Dictionary
• 98 of the Chinese diet consists of rice
  products.
• -- Teenage Burger King Employee

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Probably True, Probably False, or Insufficient
Info for Judgment

• Chuck Norris invented water.
• -- Joes Chuck Norris Web Page
• Chuck Norris gained fame for his portrayal of
  Walker, Texas Ranger.
• -- Celebrity Encyclopedia
• Chuck Norris is ambidextrous.
• -- Remark overheard at the cinema

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Whats Wrong with the Source?

• There are a trillion stars in the sky.
• -- your third grade sister
• There are nine planets in the our solar system.
• -- 1987 Halston Science Text
• NASA is the most successful space program in the
  world.
• --John James, US Astronaut

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Whats Wrong with the Source?

• I didnt steal it.
• -- Fred, convicted of 200 counts of petty
  larceny
• Whoppers cause cancer.
• -- Ronald McDonald
• This vehicle was driven by rap legend, Tupac
  Shakur, shortly before his untimely death.
• -- Ed, used-car salesman

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True or False?

• One is deemed an expert according to his/her
  education, accomplishments, reputation,
  experience, or position.
• You should disbelieve any facts presented in an
  advertisement.
• Firsthand observations are flawless.

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True or False?

• Major metropolitan newspapers, national
  newsmagazines, and network shows are generally
  credible sources of news.
• The claims of biased experts should be dismissed.
• We should be especially skeptical of talk radio
  and unknown internet sources.

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REVIEW Identifying Arguments

• Summer temperatures are reaching record highs.
  Polar ice caps are melting at an alarming rate.
  The right-wing administration may not want you to
  know it, but global warming is a serious threat.
  Just look at the scientific data!

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Anatomy of an Argument

• Conclusion The main point the arguer wants to
  convey
• Premises Claims which provide evidence or
  support for the conclusions truth
• WARNING There may be irrelevant claims,
  assertions, or rhetoric spliced into the argument.

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Dissecting an Argument

• Summer temperatures are reaching record highs.
  Polar ice caps are melting at an alarming rate.
  The right-wing administration may not want you to
  know it, but global warming is a serious threat.
  Just look at the scientific data!
• C Global Warming is a serious threat.
• P1 Summer temperatures are reaching record
  highs.
• P2 Polar ice caps are melting at an alarming
  rate.

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Another Example

• I dont care what you say. Im a believer. Santa
  Claus exists. Every Christmas, I hear him on my
  rooftop. Plus, the news stations all track his
  progress, and news anchors dont lie! My friend
  even met him at the mall once, and shes seen his
  picture before so she knows it was him.
• Conclusion Santa Claus exists.
• P1 I hear him on the rooftop each Christmas.
• P2 The news stations track him.
• P3 My friend met him once.

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Identify the Primary Conclusion

• You shouldnt eat at Long John Silvers. Twice
  Ive eaten there, and twice Ive become very
  sick.
• Experimenting on animals is wrong. Its also
  expensive. Each year, the government spends
  millions on unnecessary animal testing. If you
  value your conscience or your wallet, you should
  join the protest against animal experimentation.
  I know I will.