Logical Fallacies
Identifying and Understanding Cogent
Arguments in Business Settings
Wayne Smith, Ph.D.
Department of Management
CSU Northridge
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Informal Fallacies
• Individuals make arguments, and not all arguments
are valid.
– This invalidity is due to false premises.
• Individuals also commit fallacies, and such fallacies
are the result of incorrect or weak reasoning.
• We will focus on the latter, and refer to the former
as needed.
– The text that follows uses the terms “arguer” and “reader”.
However, the terms “speaker” and “listener”, respectively,
can be substituted as appropriate.
2
Fallacies of Reference
Fallacies of Reference have arguments
that contain premises from which the
conclusion does not flow logically.
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Appeal to Force
• This fallacy occurs when an arguer
poses a conclusion to a reader, and
the reader is compelled to accept the
conclusion only under a physical or
psychological threat made by the
arguer.
4
Appeal to Pity
• This fallacy occurs when an arguer
attempts to support a conclusion by
merely evoking pity from the reader.
5
Appeal to the People
• This fallacy occurs when an arguer uses desires (e.g., love,
esteem, admiration, value, recognition, etc.) to get the reader
to accept a conclusion.
• Direct Approach
– Directed to an entire group
• Indirect Approach
– Directed to an individual that represents the group’s values
• Variations
– Bandwagon Argument
– Appeal to Vanity
– Appeal to Snobbery
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Argument Against the Person
• This fallacy always involves two arguers. It
occurs when an arguer advances a certain
argument, and the other then responds by
directing his or her attention not to the first
person’s argument, but rather to the first
person himself/herself.
• Variations
– Abusive
– Circumstantial
– tu quoque (“you too”)
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Accident
• The fallacy of accident is committed
when a general rule is applied to a
specific case it was not intended to
cover.
• Typically, the general rule is cited in
the premises and then wrongly applied
to the specific case.
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“Straw Man”
• This fallacy occurs is committed when
an arguer distorts an opponent’s
argument for the purpose of more
easily attacking it, demolishes the
distorted argument, and then
concludes that the opponent’s real
argument has been demolished.
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“Missing the Point”
• Missing the point is a special form of
irrelevance.
• This fallacy occurs when the premises
of an argument support one particular
conclusion, but then a different
conclusion, often vaguely related to
the correct conclusion, is drawn.
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“Red Herring”
• This fallacy occurs when an arguer
diverts the attention of the reader by
changing the subject to a different but
sometimes subtly related one. By
doing so, the arguer purports to have
won the argument.
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Fallacies of Weak Induction
Fallacies of Weak Induction occur
because the connection between
premises and conclusion is not strong
enough to support the conclusion.
12
Appeal to Unqualified
Authority
• This fallacy occurs when an arguer
uses a citation that lacks credibility.
13
Appeal to Ignorance
• This fallacy occurs when the premises
of an argument state that nothing has
been proved one way or the other
about something, and the conclusion
then makes a definite assertion about
that thing.
14
Hasty Generalization
(Converse Accident)
• This fallacy occurs when there is a
reasonable likelihood that a sample is
not representative of the group. Such
a likelihood may arise if the sample is
either too small or not randomly
selected.
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False Cause
• The fallacy of false cause occurs
whenever the link between premises
and conclusion depends on some
imagined causal connection that
probably does not exist.
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“Slippery Slope”
• This fallacy is a variation of the “false
cause” fallacy. It occurs when the
conclusion of an argument rests upon
an alleged chain reaction and there is
not sufficient reason to think that the
chain reaction will actually take place.
17
Weak Analogy
• The fallacy of weak analogy is
committed when the analogy is not
strong enough to support the
conclusion that is drawn.
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Fallacies of Presumption,
Ambiguity, and Grammatical
Analogy
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“Begging the Question”
• The fallacy of begging the question
occurs whenever the arguer creates
the illusion that inadequate premises
provide adequate support for the
conclusion by leaving out a possibly
false (or shaky) key premise.
20
Complex Question
• This fallacy is committed when two or
more questions are asked in the guise
of a single question and a single
answer is then given to both of them.
21
Suppressed Evidence
• This fallacy occurs when an argument
ignores some important piece of
evidence that outweighs the presented
evidence and entails a very different
conclusion.
22
Equivocation
• This fallacy occurs when the
conclusion of an argument depends
on the fact that a word or phrase is
uses, either explicitly or implicitly, in
two different senses in the argument.
• Such arguments are either invalid or
have a false premise, and in either
case they are unsound.
23
Amphiboly
• The fallacy of amphiboly occurs when
the arguer misinterprets an
ambiguous statement and then draws
a conclusion based on this faulty
interpretation.
• Often, this fallacy arises from a
mistake in grammar or punctuation.
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Composition
• The fallacy of composition is
committed when the conclusion of an
argument depends on the erroneous
transference of an attribute from the
parts of something onto the whole.
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Division
• The fallacy is committed when the
conclusion of an argument depends
on the erroneous transference of an
attribute from a whole (or a class) onto
its parts (or members).
• This fallacy occurs is exact reverse of
composition.
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Sources
• Hurley, P. (2006), A Concise
Introduction to Logic, 9th ed.,
Australia:Thompson.
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