The Fallacy

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The Fallacy

• A fallacy is simply an error in logic. Put
  another way, a fallacy is a flaw in reasoning
  that can seriously undermine an argument. The
  following are some of the most prevalent and
  well-known fallacies.

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Emotive Language

• Fallacies that fall under the category of emotive
  language include appeals to fear, pity, flattery,
  and peer pressure.
• e.g. Without the Second Amendment which
  guarantees our right to have guns, the government
  is going to take away all our guns, and then we
  and our children will be at the mercy of rapists,
  murderers and thieves.

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Emotive Language

• e.g. The Segway is an amazing breakthrough in
  transportation technology! This amazing device
  will revolutionize the way we travel!

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EmotiveLanguage
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Straw Man

• When the arguments of the opposition are
  distorted or exaggerated, we end up with a straw
  man that is easily knocked down.
• e.g. We should have the draft reinstated. The
  whole thing is that people don't want to enter
  the military because they find it an
  inconvenience. But they should realize that there
  are more important things than convenience.

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Straw Man

• e.g. - All the people who are in favor of
  cloning want to do is bring back loved ones who
  have died. Thats playing at God and not
  realistic, so we should not consider cloning a
  reasonable idea.

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Straw Man
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Ad hominem

• From the Latin phrase to the man this fallacy
  uses a personal attack on an individual as a
  substitute for a reasoned critique of the
  individuals position.
• e.g. Governor Romney came up with a plan to
  help poor people, but why bother with it? Hes
  never been poor. What would he know about
  helping the impoverished?

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Ad hominem

• Bill "I believe that abortion is morally wrong."
  Dave "Of course you would say that, you're a
  priest." Bill "What about the arguments I gave
  to support my position?" Dave "Those don't
  count. Like I said, you're a priest, so you have
  to say that abortion is wrong. Further, you are
  just a lackey to the Pope, so I can't believe
  what you say."

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Ad hominem
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False Dilemma (Either-or)

• Sometimes called the either-or fallacy, this
  describes the strategy of presenting only two
  extreme alternatives and leaving out any middle
  ground.
• e.g. America love it or leave it.

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False Dilemma

• e.g. - "Look, you are going to have to make up
  your mind. Either you decide that you can afford
  this stereo, or you decide you are going to do
  without music for a while."

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False Dilemma
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Post Hoc Ergo Propter Hoc (Post Hoc)

• Sometimes called false cause reasoning, this
  fallacy takes its name from the Latin phrase post
  hoc ergo propter hoc which means after this,
  therefore because of this. It is assumed there
  is a cause and effect relationship between two
  events simply because one came first.
• e.g. Soon after she got married she started
  drinking a great deal. Her heavy drinking must
  have been caused by her marriage.

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Post Hoc Ergo Propter Hoc (Post Hoc)

• e.g. Our school instituted a dress code policy
  and there was a decrease in vandalism.
  Therefore, we should keep the dress code because
  it caused the drop in vandalism.
• Other factors may be at work such as increased
  security, more troublesome students being
  expelled, etc.

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Post Hoc Ergo Propter Hoc (Post Hoc)
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Slippery Slope

• This fallacy suggests that if one thing happens,
  something else will necessarily follow.
  Sometimes it is also called the domino theory.
• e.g. You should never gamble. Once you start
  gambling you find it hard to stop. Soon you are
  spending all your money on gambling, and
  eventually you will turn to crime to support your
  earnings.

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Slippery Slope

• e.g. - If we pass laws against fully-automatic
  weapons, then it won't be long before we pass
  laws on all weapons, and then we will begin to
  restrict other rights, and finally we will end up
  living in a communist state. Thus, we should not
  ban fully-automatic weapons.

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Slippery Slope
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Circular Reasoning

• Sometimes called begging the question the
  justification of the claim is simply a
  restatement of the claim.
• e.g. - "The stock market fell because of a
  technical downward adjustment."

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Circular Reasoning
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Common practice -

• Here the appeal is to popular behavior.
  Sometimes called bandwagon it is the idea that
  since everyone else is doing it, it is
  acceptable. It is sometimes called ad populum.
• e.g. Everyone takes software off the internet
  without paying for it. Its okay.

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Common practice
Everyone is selfish everyone is doing what he
believes will make himself happier. The
recognition of that can take most of the sting
out of accusations that you're being 'selfish.'
Why should you feel guilty for seeking your own
happiness when that's what everyone else is
doing, too?"

• e.g. -

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Common practice

• E.g. - Harry Potter and the Big, Giant Cauldron
  of Money must be a great book, eight million
  people have bought it.

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Common practice

• E.g. Most people in the state support the
  death penalty, so it must be the morally right
  thing to do.

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Common practice
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Red Herring

• This fallacy is a classic example of distraction
  using an unrelated point to distract the
  audiences attention from the real issue at hand.
• e.g. - "I think there is great merit in making
  the requirements stricter for the graduate
  students. I recommend that you support it, too.
  After all, we are in a budget crisis and we do
  not want our salaries affected."

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Red Herring

• e.g. - "You know, I've begun to think that there
  is some merit in the Republican's tax cut plan. I
  suggest that you come up with something like it,
  because If we Democrats are going to survive as a
  party, we have got to show that we are as
  tough-minded as the Republicans, since that is
  what the public wants."

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False Analogy

• As we know, an analogy is a comparison of two
  things showing how they have a similarity. A
  false analogy is a comparison that may seem
  acceptable on the surface, but in truth, has
  little or no similarity.

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False Analogy

• E.g.- Government is like a business therefore,
  it must be sensitive to the bottom line.

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False Analogy

• E.g.- Students should be allowed to look at
  their textbooks during an exam. Doctors look at
  x-rays during an operation, lawyers look at their
  legal briefs during a trial, so why shouldnt
  students get a chance to look at their textbooks?

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Hasty Generalization

• Making a generalization based on too small a
  sample.
• e. g. A man from England is visiting the United
  States. He spies two albino squirrels on a tree
  outside his hotel window. When calling his wife
  in England, he tells her all the squirrels in the
  USA are white.

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Hasty Generalization

• e. g. I talked to a couple of people in town
  and they were for the idea of getting rid of the
  park and putting in a big parking lot. Im sure
  most of the people in town feel the same way.

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Non sequitur

• This phrase comes from the Latin it does not
  follow. Like the false analogy, the
  non-sequitur jumps from one point to another
  without any logical reason.
• E.g. You shouldnt take Dr. Wilkies class
  because hes from New Jersey.

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Non sequitur

• This phrase comes from the Latin it does not
  follow. Like the false analogy, the
  non-sequitur jumps from one point to another
  without any logical reason.
• E.g. You shouldnt take Dr. Wilkies class
  because hes from New Jersey.

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Non sequitur