Fallacies

1
Fallacies
To error in reason is human to analyze divine!
2
Logical Fallacy?

• An error of reasoning.
• When someone adopts a position, or tries to
  persuade someone else to adopt a position, based
  on a bad piece of reasoning.
• The following is a collection of errors of
  reasoning that are
• commonly used and thus
• named.

3
Pathos

• Appeal to Emotion
• Think ASPCA commercials...
• http//www.youtube.com/watch?vAe5_QkVtXdg

4
Ethos

• Appeal to Credibility
• Trust me, I'm a doctor

5
Logos

• Appeal to Logic.
• If A is B, and B is C, then A is C.
• Man is Mortal
• Socrates is a Man
• Therefore, Socrates is Mortal.

6
Taxonomy of Fallacies

• Warning! Some fallacies are difficult to place in
  any category others belong in two or three.

7
Ad Hominem

• Ad Hominem arguments attack a persons character
  rather than that persons reasoning.
• Example Why should we think a candidate who
  recently divorced will keep his campaign promises?

8
Appeal to Force

• The writer threatens the audience, explicitly or
  implicitly, with negative consequences if the
  claim is not believed.
• Example If you do not believe in God, you will
  go to hell.

9
Appeal to Pity

• The writer begs for the approval of the claim 
  the audience may agree because they feel sorry
  for the arguer.
• I cannot get a job because the public education
  system failed me  I have to steal to  survive. 
  It is society's fault, not mine.

10
Appeal to Authority

• The writer cites authorities to show the validity
  of the claim, but the authority is not an expert
  in the field, the authority's view is taken out
  of context, or other experts of that field
  disagree with the authority quoted.
• I think that businesses should not have to limit
  the amount of pollutants they  release into the
  atmosphere because Rush Limbaugh says that there
  is no real  evidence for industrial pollutants
  causing the Greenhouse Effect.

11
Post hoc ergo propter hoc

• Post hoc ergo propter hoc, Latin for "after this,
  therefore because of this", is a logical fallacy
  that states, "Since that event followed this one,
  that event must have been caused by this one.
• More and more young people are attending high
  schools and colleges today than ever before. Yet
  there is more juvenile delinquency and more
  alienation among the young. This makes it clear
  that these young people are being corrupted by
  their education.
• https//www.youtube.com/watch?vvRJUvFG8gbE

12
Appeal to the Popular orBandwagon

• The writer bases the argument on the belief that
  if an idea is held by a large group of people, it
  is true.
• Millions of people are Marxists, so Marxist
  economic and political theories are  correct.

13
Appeal to Tradition

• The writer relies on traditional wisdom to
  support the argument.  This is a logical pitfall
  because the argument does not consider that new
  ideas could apply.
• People have believed that fish is "brain food"
  for decades, so I don't believe the  FDA when
  they claim that eating fish does not enhance the
  intellect.

14
Begging the Question orCircular Argument

• The writer defends the claim by using the
  conclusion as one of the premises to support the
  conclusion. Basically assuming the thing to be
  true that you are trying to prove.
• Example His lies are evident from the untruthful
  nature of his statements.

15
False Delimma

• The writer only presents some of the alternatives
  for solving a problem when more possibilities
  exist because the writer assumes that the list of
  alternatives created is exhaustive.
• In the United States, one can vote for either
  Democrats or Republicans.

16
Guilt by Association orPoisoning the Well

• Guilt by Association/Poisoning the Well calls
  someones character into question by examining
  the character of that persons associates.
• Example Saras friend
• Amy robbed a bank
• therefore, Sara is a
• delinquent. Or
• Dont listen to him
• because hes a loser.

17
Red Herrings

• Writers use misleading or unrelated evidence to
  support a conclusion.
• Example That painting is worthless because I
  dont recognize the artist. Or I know I forgot
  to deposit the check into the bank yesterday.
  But, nothing I do pleases you.

18
Slippery Slope

• Writers arguments suggest that one thing will
  lead to another, oftentimes with disastrous
  results.
• Example If you get a B in high school, you wont
  get into the college of your choice, and
  therefore will never have a meaningful career.