Chapter 15
PERSUASION
AND
ARGUMENT
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Because there has been
implanted in us the power
to persuade each other …
not only have we escaped
the life of the wild beasts
but we have come together
and founded cities and
made laws and invented
arts. -- Socrates
If all mankind, minus one,
were of the one opinion …
mankind would be no
more justified in silencing
that one person than he …
would be justified in
silencing mankind.
--John Stuart Mill
Persuasion is the art of
gaining fair and favorable
consideration for our points
of view
Characteristics of
Persuasive Speaking
 Urges
a choice among options
 Advocates a position
 Supporting material becomes evidence
 Listeners become agents of change
 Asks considerable audience commitment
 Credible leadership is important
 Often uses emotional appeals
 Ethical obligation is high
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Informative vs. Persuasive
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Argumentative vs. Manipulative Persuasion
 Manipulative
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persuasion
Suggestion
Colorful images
Appealing music
Attractive spokespersons
 Argumentative
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persuasion
Builds arguments based on evidence
Relies heavily on logical reasoning
Addresses judgments rather than impulses
Avoids fallacies
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Developing Evidence
 Use
facts and figures to justify advice
 Use examples to make listeners want to act
 Use narratives to involve listeners with topic
 Use expert testimony to support your ideas
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Developing Proofs
 Logos
appeals based on reason
 Pathos appeals based on emotions
 Ethos appeals based on credibility
 Mythos appeals based on cultural traditions
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Components of Ethos
 Competence
 Character
 Goodwill
 Power
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Sources of Ethos
 Ethos
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Initial credibility at beginning of a speech
Emerging credibility evolves during speech
Terminal credibility at end of a speech
 Ethos
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of the speaker
of sources cited
Reputation of periodicals
Expert testimony valued
Lay testimony adds authenticity
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Using Pathos
Portray human dimensions of a problem
 Examples can develop emotional appeals
 Personal narratives are most effective
 Cannot be too obvious
 Negative emotional appeals may backfire
 Back them up with information
 Keep delivery
understated

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Proof by Mythos
 People
value cultural identity
 Evoked by traditional stories
 Evoked by cultural symbols
 Remind us of heroes or enemies
 Calls for patriotism or other cultural
assumptions
 Can have positive
negative impact
or
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Patterns of Reasoning
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Reasoning from definition
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Reasoning from principle
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Deductive reasoning
General to specific
Reasoning from reality
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Shared understanding
Change listeners’ perspectives
Inductive reasoning
Specific to general
Reasoning from parallel cases
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Analogical reasoning
Strategic points of comparison
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Reasoning from Principle
 General
principle = major premise
 Specific issue = minor premise
 Conclusion drawn from
relationship between major
minor premises
 Yes, it’s an enthymeme (a
form of syllogism.)
and
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Argument from Principle
 Audience
must accept major premise
 Demonstrate relevance of conditions
 Explain relationship between these
 Keep reasoning free from fallacies
 Conclusion should offer clear direction
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Reasoning from Reality
 Requires
objective observations
 Needs a sufficient number of observations
 Observations should be recent
 Observations should be representative
 Observations should be relevant to conclusion
 Establish credibility of sources
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Reasoning from Parallel Cases
 Similar
to reasoning from reality
 Ties the unfamiliar to the familiar
 Concentrates on one similar situation
 Similarities must outweigh dissimilarities
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Interplay of Reasoning
– facts, examples, expert testimony
 Claim – conclusion drawn from data
 Warrant – justification of movement from
data to claim
 Backing – additional support for claim
 Reservations – exceptions to claim
 Qualifiers – possible reservations
-- Toulman Format
 Data
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Defective Evidence
Fallacies
 Slippery
slope fallacy
 Confusing fact and opinion
 Red herring fallacy
 Myth of the mean
 Flawed statistical comparisons
 Defective testimony
 Inappropriate evidence
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Defective Proof
 Ad
hominem fallacy
 Begging
the question
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Defective Reasoning
 Shaky
principle fallacy
 Omitted qualifiers
 Post hoc fallacy
 Hasty generalization
 Non sequitur fallacy
 Faulty analogy
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Design Fallacies
 Either-or
thinking
 Straw man fallacy
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