Test Bank for A Concise Introduction to
Logic, Chapter 3 (Informal Fallacies)14th
Edition by Patrick J. Hurley
fallacy - ANSa defect in an argument that arises from either a mistake in reasoning or the
creation of an illusion that makes a bad argument appear good
a fallacy can be: - ANSunsound or uncogent
if an argument is unsound or uncogent.... - ANSit has one or more false premises or it contains
a fallacy (or both)
an unsound argument - ANSa deductive argument that is invalid, has one or more false
premises, or both
formal fallacy - ANSa fallacy that may be identified by merely examining the form or structure of
an argument (found only in deductive arguments that have identifiable forms)
formal fallacy of a categorical syllogism: - ANSAll bullfights are grotesque rituals.
All executions are grotesque rituals.
Therefore, all bullfights are executions.
All A are B.
All C are B.
______
All A are C.
(If the letters C and B are interchanged, the form becomes valid, and the original argument, with
the same change introduced, also becomes valid (but unsound).)
formal fallacy of a hypothetical syllogism: - ANSIf apes are intelligent, then apes can solve
puzzles.
Apes can solve puzzles.
Therefore, apes are intelligent.
If A then B.
B.
_______
A.
, (In this case, if A and B are interchanged in the first premise, the form becomes valid, and the
original argument, with the same change, also becomes valid.)
informal fallacies are arguments that can be detected only by.... - ANSexamining the content of
an argument
(The Brooklyn Bridge is made of atoms.
Atoms are invisible.
__________
Therefore, the Brooklyn Bridge is invisible.
To detect this fallacy one must know something about bridges—namely, that they are large
visible objects, and even though their atomic components are invisible, this does not mean that
the bridges themselves are invisible.)
If Rasputin was really mad, then he deceived Czar Nicholas II. Rasputin was not really mad.
Therefore, he did not deceive Czar Nicholas II.
Formal or informal fallacy? - ANSformal fallacy
The ship of state is like a ship at sea. No sailor is ever allowed to protest orders from the
captain. For the same reason, no citizen should ever be allowed to protest presidential policies.
Formal or informal fallacy? - ANSinformal fallacy
Everything that runs has feet. The Columbia River runs very swiftly. Therefore, the Columbia
River has feet.
Formal or informal fallacy? - ANSinformal fallacy
Why it's wrong is because of the content of the argument. Not the structure but because the
information is used in the wrong ways.
If R (antecedent), F(consequent)
R
____
F
(this is a logically valid form, so we know it deals with the content)
Sarah Jessica Parker, Ben Affleck, and Julia Roberts are Democrats. Therefore, it must be the
case that all Hollywood stars are Democrats.
Formal or informal fallacy? - ANSinformal fallacy
Logic, Chapter 3 (Informal Fallacies)14th
Edition by Patrick J. Hurley
fallacy - ANSa defect in an argument that arises from either a mistake in reasoning or the
creation of an illusion that makes a bad argument appear good
a fallacy can be: - ANSunsound or uncogent
if an argument is unsound or uncogent.... - ANSit has one or more false premises or it contains
a fallacy (or both)
an unsound argument - ANSa deductive argument that is invalid, has one or more false
premises, or both
formal fallacy - ANSa fallacy that may be identified by merely examining the form or structure of
an argument (found only in deductive arguments that have identifiable forms)
formal fallacy of a categorical syllogism: - ANSAll bullfights are grotesque rituals.
All executions are grotesque rituals.
Therefore, all bullfights are executions.
All A are B.
All C are B.
______
All A are C.
(If the letters C and B are interchanged, the form becomes valid, and the original argument, with
the same change introduced, also becomes valid (but unsound).)
formal fallacy of a hypothetical syllogism: - ANSIf apes are intelligent, then apes can solve
puzzles.
Apes can solve puzzles.
Therefore, apes are intelligent.
If A then B.
B.
_______
A.
, (In this case, if A and B are interchanged in the first premise, the form becomes valid, and the
original argument, with the same change, also becomes valid.)
informal fallacies are arguments that can be detected only by.... - ANSexamining the content of
an argument
(The Brooklyn Bridge is made of atoms.
Atoms are invisible.
__________
Therefore, the Brooklyn Bridge is invisible.
To detect this fallacy one must know something about bridges—namely, that they are large
visible objects, and even though their atomic components are invisible, this does not mean that
the bridges themselves are invisible.)
If Rasputin was really mad, then he deceived Czar Nicholas II. Rasputin was not really mad.
Therefore, he did not deceive Czar Nicholas II.
Formal or informal fallacy? - ANSformal fallacy
The ship of state is like a ship at sea. No sailor is ever allowed to protest orders from the
captain. For the same reason, no citizen should ever be allowed to protest presidential policies.
Formal or informal fallacy? - ANSinformal fallacy
Everything that runs has feet. The Columbia River runs very swiftly. Therefore, the Columbia
River has feet.
Formal or informal fallacy? - ANSinformal fallacy
Why it's wrong is because of the content of the argument. Not the structure but because the
information is used in the wrong ways.
If R (antecedent), F(consequent)
R
____
F
(this is a logically valid form, so we know it deals with the content)
Sarah Jessica Parker, Ben Affleck, and Julia Roberts are Democrats. Therefore, it must be the
case that all Hollywood stars are Democrats.
Formal or informal fallacy? - ANSinformal fallacy
