Logical Fallacies

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Logical fallacies are arguments that don’t work
 They seem convincing, but fail under close examination
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What do logical fallacies do?
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Oversimplify
Assume
Fail to provide evidence
Make jumps in logic
Divert attention from the real issues
OVERALL: They damage your ethos
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Imagine you’re a reader with an opposing view
 What points would you criticize?
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Bad words: always, never, and everyone
 Sweeping generalizations lead to overstating a case
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Generalization. A conclusion about an entire group
based on a sample that’s neither large enough nor truly
representative.
 Having met several Texans, I can tell you that they are all
outgoing.
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Non sequitur. No clear connection between a conclusion
and its support. Latin for “it does not follow.”
 Congress will surely approve the education bill, since they
already passed the voting reform bill.
 Rabbits are a symbol of the American Dream because Lennie
and George work on a ranch.
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Forced Hypothesis. The explanation is forced because
there’s not enough evidence. It often ignores
alternative explanations or counter-arguments.
 Ex. Everyone clapped after Sophia’s recital, so she must be an
excellent pianist.
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Slippery Slope. You cannot permit something because it
leads to extreme consequences.
 Ex. If we allow the government to legalize marijuana, it will
next legalize cocaine and heroin. Before long, our kids will all
be addicted to hard drugs.
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Begging the Question or Circular Reasoning. The claims
of an argument assume the conclusion is true.
 Ex. Using a cell phone while driving is hazardous, so it should
be completely outlawed.
▪ This argument doesn’t offer proof that driving while using a phone is
dangerous, but simply asserts that it is and expects readers to agree.
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Red Herring. An irrelevant topic is introduced, diverting
attention from the relevant debate.
 Ex. The government cannot begin to improve education until
it balances the budget.
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Straw Man. An argument that distorts the opposition.
 Ex. People who oppose this education bill want us to go back
to the age of one-room school houses. Obviously, we live in a
different era.
▪ The author exaggerates the opposing side’s position, creating a “straw
man.” A man made of straw is easy to defeat.
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Ad Populum. An argument that appeals to an audience’s
presumed shared values. Latin for “to the people.”
 Ex. As good Texans, we want what’s best for our beloved state,
which is why we can all agree that Cowboy Bob is the best
candidate for governor.
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