Phi 120

1. Chapter 5
Informal Fallacies
The aim of this tutorial is to help you learn to
recognize and resist fallacious arguments.
Copyright © 2021 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

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Fallacies Are Dangerous
Fallacies, or flawed arguments, are often used by cult
recruiters on college campuses to target freshmen.
• Critical thinking is the antidote to fallacious arguments. By
recognizing fallacies and other types of flawed arguments, we can
protect ourselves against those seeking to control or manipulate us.

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Fallacies: Formal and Informal
An argument is the process of supporting a claim by
providing reasons or evidence for that claim.
• An argument contains a fallacy when it appears to be initially
correct but upon further examination is found to be incorrect.
• In formal fallacies, the form of the argument itself is invalid.
• An informal fallacy is mistaken reasoning that occurs when an
argument is psychologically or emotionally persuasive but logically
incorrect.

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Hot or Not? 1
Is the use of fallacies a legitimate
political campaign tactic?

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Fallacies of Ambiguity 1
Arguments that contain ambiguous words or
phrases, sloppy grammar, or confusion between two
closely-related concepts can lead to fallacies of
ambiguity.

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Fallacies of Ambiguity 2
Four types of fallacies of ambiguity.
• Equivocation occurs when a key term in an argument is
ambiguous—when it has more than one meaning.
• Amphiboly occurs when an argument contains a grammatical
mistake.
• Fallacies of accent occur when an argument’s meaning changes
depending on which words or phrases are emphasized.
• Fallacies of division occur we make an erroneous inference from
the characteristics of an entire set or group about a member of the
group or set.
• Fallacies of composition occur when a characteristic of a member
of a group is erroneously assumed to be characteristic of the whole
group.

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Tiger Woods and His Family
Ezra Shaw/Getty Images
Tiger Woods is a good golfer, therefore Tiger
Woods is a good husband.

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Danny DeVito
Gilbert Carrasquillo/Film Magic/Getty Images
Men are taller than women. Danny DeVito is a man.
Therefore, Danny DeVito is taller than the average woman.

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Fallacies of Relevance 1
In fallacies of relevance, one or more of the premises is
logically irrelevant, or unrelated, to the conclusion.
Fallacies of relevance include:
• Personal attacks or ad hominem fallacies.
• Appeals to force or scare tactics.
• Appeals to pity.
• Popular appeals.

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Fallacies of Relevance 2
• Appeals to ignorance.
• Hasty generalizations.
• Straw man fallacies
• Red herrings.

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Ad Hominem and Appeal to Force
• The ad hominem fallacy occurs when we disagree with
another’s conclusion and attack them personally instead
of presenting a valid counterargument.
• The appeal to force fallacy occurs when we use or
threaten to use force in an attempt to get others to back
down or accept our conclusions.

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Ad Hominem Fallacy
Ingram Publishing
The Ad Hominem fallacy may occur
between people in personal relationships.

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Darwin’s Descent from the Apes
GraphicaArtis/Hulton Archive/Getty Images

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Appeal to Pity and Popular Appeal
The appeal to pity fallacy occurs when we try to evoke
feelings of pity in others when pity is irrelevant to the
conclusion.
The fallacy of popular appeal occurs when we appeal to
popular opinion to gain support for our conclusion.
• This fallacy includes the bandwagon approach and the snob
approach.

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"I Shouldn't Get a Ticket Because
Everyone Speeds"
Katarzyna Białasiewicz/123RF

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Appeal to Ignorance and Hasty
Generalization
• The appeal to ignorance fallacy occurs when we try to
argue that something is true because no one has proven
it to be false.
• The fallacy of hasty generalization occurs when we
generalize from a sample that is too small or biased.

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Hot or Not? 2
Does celebrity endorsement of a
product make you more likely to buy
that product?

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"You've Come a Long Way, Baby."
The Advertising Archives
Access the text alternative for slide images

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"I Want to Be Like Victoria Beckham, so I'll
Buy the Type of Purse She Is Carrying."
Jun Sato/Wire Images/Getty Images

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YouTube Film "Innocence of Muslims"
Provoked Protests
1000 Words/Shutterstock
The YouTube film "Innocence of Muslims"
provoked protests throughout the Muslim world.

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Straw Man and Red Herring Fallacies
• The straw man fallacy occurs when a person distorts or
misrepresents the opponent’s argument, making it
easier to knock down or refute.
• The red herring fallacy occurs when a person tries to
sidetrack an argument by going off on a tangent and
bringing up a different issue directed toward a different
conclusion.

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Straw Man Fallacy
Maskot/Image Source
Opposition to same-sex marriage is sometimes
based on the straw man fallacy.

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Fallacies Involving Unwarranted
Assumptions 1
Fallacies involving unwarranted assumptions occur
when an argument includes an assumption that is not
supported by evidence.
Fallacies involving unwarranted assumptions include:
• Begging the question
• Inappropriate appeal to authority
• Loaded question
• False dilemma

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Fallacies Involving Unwarranted
Assumptions 2
• Questionable cause
• Slippery slope
• The naturalistic fallacy.

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Begging the Question and
Inappropriate Appeal to Authority
The begging the question fallacy occurs when an
argument’s conclusion is simply the rewording of its
premise.
• This fallacy is also known as circular reasoning.
The inappropriate appeal to authority fallacy occurs
when we look to an authority in a field that is unrelated or
not under investigation.

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A Uniform Gives the Idea That the Person Is
an Authority in Fields That May Be beyond
His or Her Expertise
Jessica Leigh-Pool/Getty Images

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Loaded Question and False Dilemma
The loaded question fallacy occurs when a question
asked assumes a particular answer to another unasked
question.
The false dilemma fallacy reduces responses to complex
issues to an either/or choice.
• By doing so, this fallacy polarizes stands on issues and ignores
common ground or other solutions.

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It's Not a Choice of Only Oil or
Alternative Energies
Ron Thomas/Getty Images

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Questionable Cause and Slippery
Slope
• The questionable cause or post hoc fallacy occurs
when a person assumes, without sufficient evidence,
that one thing is the cause of another.
• According to the slippery slope fallacy, if we permit a
certain action, then all actions of this type, even extreme
ones, will soon be permissible.

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Ryan White
Kim Komenich/The LIFE Images Collection/Getty Images
Ryan White was a victim of the fallacy of
questionable cause.

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Judith Sheindlin, Popularly Known As
"Judge Judy"
Donaldson Collection/Michael Ochs Archives/Getty Images

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“The End of the Curse"
Library of Congress Prints & Photographs Division [LC-DIG-ggbain-32385]
Babe Ruth jinxed the Red Sox in 1920. Their world series
win in 2004 was attributed to "the end of the curse."

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The Naturalistic Fallacy
The naturalistic fallacy is based on the unwarranted
assumption that what is natural is good or morally
acceptable and that what is unnatural is bad or morally
unacceptable.

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Same-Sex Parents Are Discriminated
David McNew/Getty Images
Same-sex parents are often discriminated against because
many people only see "parents" as a mother and father.

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Strategies for Avoiding Fallacies 1
Once you have learned to identify informal fallacies, the
next step is to develop strategies to avoid them.
The following strategies are recommended:
• Know yourself and the fallacies you are most
susceptible to.
• Build your self-confidence and self-esteem.
• Cultivate good listening skills; study others’ arguments
for fallacies.
• Avoid ambiguous, vague terms and faulty grammar.

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Strategies for Avoiding Fallacies 2
• Avoid confusing the soundness of an argument with the character
or circumstances of the person making the argument.
• Know your topic, and do your research.
• Adopt a skeptical “default” position.
• Watch your body language. Avoid inflammatory actions.
• Don’t be set on winning every argument.
• Seek the truth, not victory.

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Conclusions
• Use of fallacies in communication can damage
relationships and impair sound critical thinking.
• Identification and avoidance of fallacies through the use
of effective strategies can improve our relationships with
others and increase the credibility of our arguments.

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Perspectives on Gun Control
Brennan Linsley/AP Images