Critical Thinking

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Critical Thinking

• Dont Be Fooled by Bad Arguments

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First, what are arguments?

• Distinguish arguments from explanations
• Arguments are the assertion of a conclusion from
  reasons that are better known than the
  conclusion.
• Explanations are the assertion of reasons for a
  conclusion that is better known than those
  reasons.

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Ad Hominem

• Argumentum ad Hominem (Argument to the Person)
  Attacking the arguer instead of their argument.
• Famous response to an ad hominem attack
• I may be the devils brother, sir,
• but you still havent answered my argument.
• 3 Kinds of ad Hominem arguments
• Abusive ad Hominem
• I believe murderers should die for the sake of
  their victims family.
• Only a total jerk would want anyone to die!
• does the speaker being a jerk have anything to
  do with whether capital punishment is justified
  based on concern for the victims family?

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Ad Hominem

• Circumstantial ad Hominem
• I believe murderers should die for the sake of
  the victims family.
• Well, since your cousin was murdered, it isnt
  hard to see why you feel that way.
• Tu Quoque (you too)
• I believe murderers should die for the sake of
  the victims family.
• Well, I recall you defending your Uncle when he
  was convicted you werent suggesting he die for
  the family of the guy he shot!

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Appeal to Ignorance

• Appeal to Ignorance (ad Ignorantiam)
• Arguing from a lack of knowledge
• No one has proven X true, (or false)
• X is false (or true)
• God does not exist.
• Says who?
• Well, no one has proven God exists, so he
  doesnt.
• God exists.
• Says who?
• Well, no one as proven God doesnt exist, so he
  does.

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Appeal to Ignorance, cont.

• Exceptions (below are good arguments (pretty
  good))
• Guys innocent.
• Says who?
• Well, he hasnt been proven guilty, so he is
  innocent.
• There is no crocodile in the hall.
• Says who?
• Well, no one has proven theres a crocodile in
  the hall, so there isnt.

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Appeal to the Majority / Tradition

• Appeal to the Majority
• The fallacy has the form
• X is popular
• X is true
• Direct Approach appeal directly to the crowd of
  people use emotive language to create mob
  mentality support for a conclusion. Political
  speeches often good examples?
• Indirect Approach appeal indirectly to the crowd
  by appealing directly to individuals and their
  relationship to the crowd also called a
  Bandwagon Argument
• Come on everyone in this class smokes crack
  ... you should take a hit!

Individual
crowd
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Appeal to the Majority / Tradition

• Appeal to the People (Argumentum ad Populum)
• Ad Populum has the form
• X is popular
• X is true
• When the majoritys opinion becomes enshrined
  over time it becomes a tradition. Think of Appeal
  to Tradition as an instance of Indirect Appeal to
  the Majority
• If your school had a tradition of crack smoking,
  the example below would be appeal to tradition.
• Come on everyone in this class smokes crack
  ... you should take a hit!

Individual
crowd
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Appeal to Feelings Fear

• Appeal to Force or Fear
• Supporting or avoiding a conclusion by threats
• Worst case
• when debates get derailed by jeering or shouting
  down an arguer so that the argument cant be
  heard.
• More subtle case
• I think we should choose xBox over Playstation
  because its online multiplayer stuff is better.
• How about I stomp your guts out? How would that
  be?
• Committing Appeal to Fear is less an error in
  reasoning, more a bullying tactic. Either way,
  the response is irrelevant to the quality of the
  argument.

10
Appeal to Feelings Pity

• Appeal to Pity (Argumentum ad Misericordiam)
• Im afraid going 70 in a 25mph zone means you
  deserve this ticket, Ms. Garcia.
• No, Judge, I have three kids, late bills, and
  work two jobs I cant deserve this speeding
  ticket!
• Is the sorry state of the arguer logically
  relevant to deserving the ticket?
• Might the judge considering it in sentencing?

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Absolutizing Rules

• Absolutizing Rules (Misapplying a Rule)
• Yes I told the axe murderer where the little
  girl was! if you check your bible, youll find
  Thou Shalt Not Lie

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Double Standards

• To have a double standard is to apply two
  different rules or judgments to one and the same
  thing or kind of thing.
• What a jerk! She totally shouldnt be sitting
  with that guy when she has a boyfriend!
• Yeah, but you sit with Betty sometimes and you
  have a girlfriend!
• Yeah, but thats different. Im a guy!

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Double Standards

• Notice the relationship with Tu Quoque, the You
  too! fallacy
• Having a double standard doesnt make the claim
  shes a jerk false. It still might be true. It
  simply means that if its true, hes a jerk is
  true as well.
• On the flip side, perhaps its false that shes
  a jerk for sitting with a boy. It will follow
  that hes a jerk for sitting with a girl is
  false.

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Bifurcation (False)

• False Bifurcation
• False Dichotomy
• Faulty Dilemma
• Black and White Thinking
• Either/Or fallacy
• False Choice
• Either ice cream or tantrum you choose! (from
  kid)
• Either exercise or heart attack you choose!
  (from Doc)

Ultimatums are rarely False Bifurcations, but
can be
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Bifurcation (False)

• Note how premises are red, just like the
  conclusions. Bifurcation is a fallacy of
  presumption.
• With multiplication, 12 is either 6x2 or 4x3
  so, which is it, kid?
• When cooking chicken, its either frying or
  baking. So, what do you want to do?
• Note also there are many genuine bifurcations,
  trifurcations, tetrafurcations, etc.
• Either the universe was created by an intelligent
  being or it is eternal or it had a natural
  origin.
• Its either chocolate or vanilla thats all we
  have.

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Hasty Judgment

• Missing the Point
• So, you say Bill punched Bob in the nose? All
  right, better get Bob straight to the emergency
  room!
• Sometimes MtP is jumping to a distant conclusion.
• Sometimes MtP is just missing the point.
• Thats a priceless Steinway! Not anymore.
• If youre not out of here in 5 seconds! ...
• Ah, I could easily be out of here in three!

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Hasty Generalization

• Hasty Generalization (Converse Accident)
• Taking a small sample, and inferring from it all
  or most of that kind are the same.
• My cabbie in New York City was surly, so, all
  cabbies in NYC are surly.
• Exceptions
• This Root Beer, Roundys, is blah, so all
  Roundys Root Beer is blah.
• This Pit Bull (Rottweiler, Tarantula, Python,
  etc.) is dangerous, so, all Pit Bulls
  (Rottweilers, Tarantulas, Pythons, etc.) are
  dangerous.

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Hasty Generalization

• Two more things regarding the logic of danger
  (2)
• When people say Pit Bulls, for instance, are
  dangerous, they plainly dont mean to include
  dead ones, very old ones, very young ones. Their
  statement is perhaps elliptical for, these
  healthy adult dogs can kill you and animals are
  unpredictable. Be on guard! You must decide if a
  statement is straight-forward or elliptical based
  on context, knowledge of the speaker, or by
  asking, if possible.
• Risk assessment logic Risk assessments have 2
  parts
• probability and,
• severity.
• Some things have very low probabilities of harm,
  but are dangerous because of high severity.
  Commonly believed dangerous things
• your weird looking neighbor,
• flying in a commercial jet,
• driving a car without a seatbelt,
• playing just one round of Russian Roulette,
• hitchhiking.
• All have very low probabilities of harm. How then
  are they dangerous?

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Quick Quiz

• We should give that new position to Frank
  Thompson. Frank has six hungry kids to feed, and
  his wife needs an operation to save her eyesight.

aH ad Hominem AF Appeal to Feelings Ape Appeal to the Majority / T AI Appeal to Ignorance Ab Absolutizing Rules DS Double Standard FB False Bifurcation HJ Hasty Judgment NF No Fallacy
20
Quick Quiz

• Professor Pearsons arguments in favor of the
  theory of evolution should be discounted. Pearson
  is a cocaine-snorting sex pervert and, according
  to some reports, a member of the communist party.

aH ad Hominem AF Appeal to Feelings Ape Appeal to the Majority / T AI Appeal to Ignorance Ab Absolutizing Rules DS Double Standard FB False Bifurcation HJ Hasty Judgment NF No Fallacy
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Quick Quiz

• Some of you oppose the appointment of David Cole
  as new sales manager. Upon further consideration,
  I am sure you will find him suitable for the job.
  If not confirmed, it may be necessary to make
  severe personnel cutbacks in your department.

aH ad Hominem AF Appeal to Feelings Ape Appeal to the Majority / T AI Appeal to Ignorance Ab Absolutizing Rules DS Double Standard FB False Bifurcation HJ Hasty Judgment NF No Fallacy
22
Quick Quiz

• You should read Irving Stones latest novel right
  away. It has sold over a million copies, and
  nearly everyone in the Manhattan cocktail circuit
  is talking about it.

aH ad Hominem AF Appeal to Feelings Ape Appeal to the Majority / T AI Appeal to Ignorance Ab Absolutizing Rules DS Double Standard FB False Bifurcation HJ Hasty Judgment NF No Fallacy
23
Quick Quiz

• Actress Andie MacDowell says that its healthy to
  drink milk. But the dairy industry pays MacDowell
  thousands of dollars to make these ads.
  Therefore, we shouldnt take her testimonials too
  seriously.

aH ad Hominem AF Appeal to Feelings Ape Appeal to the Majority / T AI Appeal to Ignorance Ab Absolutizing Rules DS Double Standard FB False Bifurcation HJ Hasty Judgment NF No Fallacy
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Quick Quiz

• Dr. Morrison has argued that smoking is
  responsible for the majority of health problems
  in this country and that every smoker concerned
  about his or her health should quit.
  Unfortunately, however, we must consign Dr.
  Morrisons argument to the trash bin. Only
  yesterday I saw none other than Dr. Morrison
  himself smoking a cigar.

aH ad Hominem AF Appeal to Feelings Ape Appeal to the Majority / T AI Appeal to Ignorance Ab Absolutizing Rules DS Double Standard FB False Bifurcation HJ Hasty Judgment NF No Fallacy
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Quick Quiz

• If you give Jane a cookie, shell want a glass of
  milk. Then, she wont be hungry for her supper!

aH ad Hominem AF Appeal to Feelings Ape Appeal to the Majority / T AI Appeal to Ignorance Ab Absolutizing Rules DS Double Standard FB False Bifurcation HJ Hasty Judgment NF No Fallacy
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Quick Quiz

• Ellen is a mean drunk. I wouldnt invite her to
  your kegger, if I were you.

aH ad Hominem AF Appeal to Feelings Ape Appeal to the Majority / T AI Appeal to Ignorance Ab Absolutizing Rules DS Double Standard FB False Bifurcation HJ Hasty Judgment NF No Fallacy
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Quick Quiz

• Probably no life exists on Venus. Teams of
  scientists have conducted exhaustive studies on
  the planets surface and atmosphere, and no
  living organisms have been found.

aH ad Hominem AF Appeal to Feelings Ape Appeal to the Majority / T AI Appeal to Ignorance Ab Absolutizing Rules DS Double Standard FB False Bifurcation HJ Hasty Judgment NF No Fallacy