Transcript Chapter 5 Logical Fallacies I Fallacies of Relevance

Chapter 5
Logical Fallacies I
Fallacies of Relevance
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• Chapter 5: Logical Fallacies--1
• Assessing Relevance
• Determine whether the premises in the
following arguments are positively relevant,
negatively relevant, or irrelevant to the
conclusion.
• 1. Felix is a parrot. So Felix has feathers.
• 2. Halle is fifteen-years-old. So, Halle is a
senior in high school.
• 3. Figure X is a triangle. So, figure X is a
square.
• Chapter 5: Logical Fallacies--1
• Assessing Relevance
• Determine whether the premises in the
following arguments are positively relevant,
negatively relevant, or irrelevant to the
conclusion.
• 1. Felix is a parrot. So Felix has feathers.
• 2. Halle is fifteen-years-old. So, Halle is a
senior in high school.
• 3. Figure X is a triangle. So, figure X is a
square.
• 1. positively relevant
• 2. negatively relevant
• 3. negatively relevant
• Indicate in the space provide whether the
following statements are true (T) of false (F).
• ______ 1. A fallacy is an argument that contains
at least one false premise.
• ______ 2. Fallacies of relevance are fallacies
that occur because the premises, though
logically relevant to the conclusion, fail to
provide sufficient evidence for the
conclusion.
• ______ 3. A statement is positively relevant to
another statement if it counts in favor of
that
statement.
• Indicate in the space provide whether the following
statements are true (T) of false (F).
• ______ 1. A fallacy is an argument that contains at least
one false premise.
• ______ 2. Fallacies of relevance are fallacies that occur
because the premises, though logically relevant to the
conclusion, fail to provide sufficient evidence for the
conclusion.
• ______ 3. A statement is positively relevant to another
statement if it counts in favor of
that statement.
• 1. F
• 2. F
• 3. T
• Identifying Fallacies
• Identify the fallacies of relevance committed in the
following passages. If no fallacy is committed, write "no
fallacy."
• 1. Gambling is wrong, because it's wrong to play at
games of chance for stakes.
• 2. It would be a mistake to appoint Pete Dobson as
Superintendent of Schools. Mr. Dobson has twice been
convicted of child endangerment and he was recently
charged with embezzlement.
• 3. In a recent issue of Stogey magazine, Julio Fumar
argues that Honduran cigars are better than Cuban
cigars. But Fumar's argument isn't worth the paper it's
printed on. Fumar is biased against Cuba because the
Castro regime imprisoned his parents.
• Identifying Fallacies
• Identify the fallacies of relevance committed in the
following passages. If no fallacy is committed, write "no
fallacy."
• 1. Gambling is wrong, because it's wrong to play at
games of chance for stakes.
• 2. It would be a mistake to appoint Pete Dobson as
Superintendent of Schools. Mr. Dobson has twice been
convicted of child endangerment and he was recently
charged with embezzlement.
• 3. In a recent issue of Stogey magazine, Julio Fumar
argues that Honduran cigars are better than Cuban
cigars. But Fumar's argument isn't worth the paper it's
printed on. Fumar is biased against Cuba because the
Castro regime imprisoned his parents.
• 1. begging the question
• 2. no fallacy
• 3. attacking the motive
• Chapter 6: Logical Fallacies--2
• True/False
• Indicate in the space provided whether the
following statements are true (T) of false (F).
• ______ 1. Critical thinkers never accept a claim
on the mere say-so of another.
• ______ 2. If a person accepts a claim on the
say-so of an alleged witness or authority, and
there is good reason to believe that the
alleged witness or authority is biased, then the
person commits the fallacy of inappropriate
appeal to authority.
• True/False
• Indicate in the space provided whether the
following statements are true (T) of false (F).
• ______ 1. Critical thinkers never accept a claim
on the mere say-so of another.
• ______ 2. If a person accepts a claim on the
say-so of an alleged witness or authority, and
there is good reason to believe that the
alleged witness or authority is biased, then the
person commits the fallacy of inappropriate
appeal to authority.
• 1. F
• 2. T
• ______ 4. Some claims are so inherently
controversial that they cannot be settled by
appeals to expert opinion.
• ______ 5. The following argument commits
the fallacy of appeal to ignorance: "No one
has ever seen Billie Jenkins ride his
bike to school. So, probably Billy Jenkins
rarely if ever rides his bike to school."
• ______ 6. The fallacy of false alternatives
need not be explicitly expressed in
"either…or" form.
• ______ 4. Some claims are so inherently
controversial that they cannot be settled by
appeals to expert opinion.
• ______ 5. The following argument commits the
fallacy of appeal to ignorance: "No one
has
ever seen Billie Jenkins ride his bike to school.
So, probably Billy Jenkins rarely if ever rides his
bike to school."
• ______ 6. The fallacy of false alternatives need
not be explicitly expressed in
"either…or"
form.
• 4. T
• 5. F
• 6. T
• Identifying Fallacies
• Identify the fallacies of insufficient evidence committed in
the following passages. If no fallacy is committed, write
"no fallacy."
• 1. Giving half your money to charity is either morally
obligatory or morally prohibited. But giving half your
money to charity is not morally prohibited. In fact, it would
be highly praiseworthy. Therefore, giving half your money
to charity is morally obligatory.
• 2. IRS agent: Mr. Peckinsniff, there is nothing in
these documents that proves that you haven't been
cheating on your taxes. Therefore, I must assume that
you have been cheating on your taxes.
• 3. Kids play too many video games. That's why there's so
much juvenile crime today.
• Identifying Fallacies
• Identify the fallacies of insufficient evidence committed in the
following passages. If no fallacy is committed, write "no fallacy."
• 1. Giving half your money to charity is either morally obligatory or
morally prohibited. But giving half your money to charity is not
morally prohibited. In fact, it would be highly praiseworthy. Therefore,
giving half your money to charity is morally obligatory.
• 2. IRS agent:
Mr. Peckinsniff, there is nothing in these
documents that proves
that you
haven't been cheating on your taxes. Therefore, I must
assume that you have been cheating on your
taxes.
• 3. Kids play too many video games. That's why there's so much
juvenile crime today.
• 1. false alternatives
• 2. appeal to ignorance
• 3. questionable cause