Logical Fallacies

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Logical Fallacies
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Shifting the burden of proof not proving an
assertion leaving it up to the other side to
disprove
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Begging the question treating an unproved
assertion as proved and using it as a basis for
further assertions
Also known as .
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Circular Logic restating an effect as its own
cause

• This product is environmentally friendly because
  it doesnt pollute the atmosphere.
• Abortion is wrong because it is immoral.
• All useless laws such as Reform Bill 13 should be
  repealed.

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Extension exaggerating a point out of all
logical proportion-- because something happened
before, it will happen again
If we do it for you, well have to do it for
everyone.
Someone who smokes will drink, and God only
knows what someone who drinks will do.
Psycho was a great movie American Psycho must
be great too.
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Post Hoc Ergo Propter Hoc after this, therefore
because of this -- because A happened first, it
caused B.
The basketball team lost the game tonight because
it rained this afternoon.
I tripped because I walked under the ladder.
Nearly all heroin users started with marijuana.
Marijuana use obviously leads to the use of hard
drugs.
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Argumentum ad Hominem attacking the person not
the issue

• Bill Clinton cheated on his wife, so he was a
  lousy President.
• Who cares what that fat, loudmouth Rush Limbaugh
  thinks anyway?

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Red Herring raising false issues to detract
from the real issue

• We better not provide prescription benefits to
  senior citizens because debt is a burden on our
  children.
• Guns dont kill people people kill people.
• False clues used in mystery stories are also
  called red herrings.

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Stereotyping describing an individual or group
based upon preconceptions of the group's
characteristics

• All chihuahus love tacos!
• Teenagers who pierce their bodies have no respect
  for authority.

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Either/Or Fallacy allowing only two possible
alternatives

• If guns are outlawed, only outlaws will have
  guns.
• America, love it or leave it!
• If you oppose the death penalty, you support
  murderers.
• If you think education is expensive, try
  ignorance

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Oversimplified Causefailing to identify all
causes and types of causes

• World War I was caused by the assassination of
  Archduke Ferdinand in Sarajevo.
• The government had a deficit last year because
  its still borrowing to pay entitlements.
• I crashed into the car in front of me because the
  driver was going too slowly.

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Argument from Ignoranceif something is not
disproved, then it must be true

• There is no proof that alien abductions have not
  occurred therefore, some of the abductees must
  be telling the truth.
• The supercollider would never have paid for
  itself.

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Argument from AuthorityCelebrity
Endorsementcredibility assumed from well-known
figures
Air Jordan 15 (men)150.00Inspired by two
unequaled air travelers the X-15 and Michael
Jordan. The Air Jordan 15 features the richest
full-grain leathers in a woven pattern. The Pebax
heel counter holds the foot in place and the
midfoot shank provides arch support. Zoom Air
cushioning in the heel and forefoot is
low-profile and responsive and the seamless
construction inner sleeve assures a great fit.
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Bandwagon or ad populum because everyone else
agrees, wants to, or does so

• A million people are smarter than one.
• A majority of the people polled believe power
  lines cause cancer.
• Everybodys doing it.

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Non-Sequitur conclusion not necessarily the
result of the facts
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Faulty Analogyusing invalid comparisons to prove
a point

• Apples are a better food than oranges because you
  can eat the skins.
• I have to balance my checkbook why shouldnt the
  federal government have to?

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Questionable Statistics

• Statistics should be questioned when the sample
  is
• too small
• unrepresentative
• asks loaded questions

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