Faulty Reasoning

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Faulty Reasoning
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What is a fallacy?

• fallacy is a generic term that indicates an
  error or weakness in an argument or thought
  process. (Ziegmuller and Kay)
• The source of a fallacy may be found in the data,
  the reasoning process, the language, or the
  strategic or psychological basis of the argument.

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Common fallacies

• Red Herring introduces an irrelevant issue in
  order to divert attention from the subject under
  discussion.
• Example
• The real problem is not eliminating handguns
  the real problem is that pawnshops that sell guns
  are controlled by the Mafia.

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More

• Ad Hominem (mudslinging) substitutes an attack
  on the person for discussion of the real subject
  under discussion.
• Example
• Tony is an awful musician and is not sensitive
  enough to chair such an important committee.

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More

• False dilemma (either-or) forces listeners to
  choose between two alternatives when more than
  two exist.
• Example
• Either more people should start volunteering
  their time to work for their community, or your
  taxes will increase.

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More

• Bandwagon assumes that because something is
  popular, it is therefore good, correct, or
  desirable.
• Example
• Most people agree with me that we spend too much
  time worrying about Medicare.

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More

• Slippery slope assumes that taking a first step
  will lead inevitably to a second step and so on
  down the slope to disaster.
• Example
• Passing federal laws to control the amount of
  violence on television is the first step in a
  process that will result in absolute government
  control of the media and total censorship over
  all forms of artistic expression.

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More

• Hasty generalization A person who reaches a
  conclusion from too little evidence or
  nonexistent evidence.
• Example
• Its clear that our schools cant educate
  children well, because my niece went to school
  for six years and she still cant read at her
  grade level.

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More

• Post Hoc, Ergo Propter Hoc (After this,
  therefore because of this or false cause)
  assume that because one event comes after
  another, the first event must necessarily be the
  cause of the second.
• Example
• The decline of morals in this country is caused
  by excessive government spending.

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Lets test your knowledge!

• I dont see any reason to wear a helmet when I
  ride a bike. Everyone bikes without a helmet.
• Answer-bandwagon fallacy
• Its ridiculous to worry about protecting
  Americas national parks against pollution and
  overuse when innocent people are being endangered
  by domestic terrorists.
• Answer-red herring fallacy

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More

• There can be no doubt that the Great Depression
  was caused by Herbert Hoover. He became
  President in March 1929, and the stock market
  crashed just seven months later.
• Answer-Post Hoc, Ergo Propter Hoc or false cause.

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More

• If we follow the school board to spend money
  remodeling the gymnasium, next they will want to
  build a new school and give all the teachers a
  huge raise. Taxes will soar so high that
  businesses will leave and then there will be no
  jobs for anyone in this town.
• Answer-Slippery slope fallacy

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More

• I cant support Representative Freys proposal
  for campaign finance reform. After all, he was
  kicked out of law school for cheating on an
  exam.
• Answer-ad hominen fallacy.

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More

• One nonsmoker, interviewed at a restaurant,
  said, I can eat dinner just fine even though
  people around me are smoking. Another,
  responding to a Los Angeles Times survey, said,
  I dont see what all the fuss is about. My wife
  has smoked for years and it has never bothered
  me. We can see that secondhand smoke does not
  cause a problem for most nonsmokers.
• Answer-hasty generalization.

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More

• Our school must either increase tuition or cut
  back on library services for students.
• Answer-False dilemma or either-or fallacy.

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Conclusion

• Use fallacies as a way to identify fault in
  others arguments as well as our own.
• By exposing fallacies in arguments it helps build
  strong sound reasoning.