Chapter 14 Methods of Persuasion
 I. interest in methods of persuasion
 A. studies in strategies and tactics of persuasion for thousands
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of years
B. why are they persuaded?
1. credibility
2. evidence
3. reasoning
4. ideas or language.
 II. Credibility
 A. importance
 1. The more favorably listeners view a speaker, the more likely
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they are to accept what the speaker says.
2. A speaker’s credibility will vary from audience to audience and
topic to topic.
B. two primary factors: competence and character
1. Competence refers to how an audience regards a speaker’s
intelligence, expertise, and knowledge of the subject.
2. Character refers to how an audience regards a speaker’s
sincerity, trustworthiness, and concern for the well-being of the
audience.
 C. three types of credibility
 1. Initial credibility is the audience’s perception of the
speaker before the speech begins.
 2. Derived credibility is produced by everything a speaker
says and does during the speech.
 3. Terminal credibility is the audience’s perception of the
speaker at the end of the speech.
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D. three strategies to enhance credibility
1. explaining their competence
a. stress their research on the speech topic.
b. stress special knowledge of the topic gained through personal experience.
2. establishing common ground with the audience.
a. meaning showing respect for and identifying with the audience’s values and
beliefs.
b. especially important in the introduction of a persuasive speech.
3. delivering their speeches fluently, expressively, and with conviction.
a. Fluent, animated delivery greatly enhances a speaker’s credibility.
b. Speaking with genuine conviction also does a great deal to strengthen a
speaker’s credibility.
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 III. evidence
 Evidence consists of examples, statistics, and testimony used to
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prove or disprove something.
Speakers must support their views with evidence.
Four tips
specific evidence
novel evidence (new facts and figures)
evidence from credible sources
making clear the point of the evidence
 IV. reasoning
 Reasoning is the process of drawing a conclusion based on
evidence
 two major concerns:
 whether the reasoning is sound
 whether the audience agree with the reasoning
 to use reasoning from specific instances
 to progress from a number of particular facts to a general conclusion
 three guidelines
 to beware of hasty generalizations based on insufficient evidence
 to be careful with their wording so as not to overstate the facts
 (It certainly seems fair to conclude that international
cooperation is needed to fight H1N1 for the health of world’s
people)
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to reinforce the argument with statistics or testimony
 to use reasoning from principle
 to move from a general principle to a specific principle
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 (syllogism: The United States Constitution guarantees all U.S
citizens the right to vote.
 Women are U.S. citizens.
 Therefore, the United States Constitution guarantees women
the right to vote.)
 two basic guidelines:
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to make certain the audience will accept the general principle
to make sure that the audience will accept the minor premise
 eg.
 Specific purpose: To persuade my audience to limit their
consumption of fast foods, canned goods, and frozen foods
because of their excessive salt content.
 Excessive consumption of salt is unhealthy.
 Fast foods, canned goods, and frozen foods contain excessive
amounts of salt.
 Therefore, excessive consumption of fast goods, canned
goods, and frozen foods is unhealthy.
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 hypertension, or high blood pressure (major cause of heart
disease, kidney disease, and stroke); in northern Japan and
tribes of New Guinea.
 human body needs 230 milligrams of sodium per day, but
many fast foods, canned foods and frozen foods deliver
several times that amount in a single serving. (examples:
McDonald’s Big Mac: 1510 milligrams…)
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 to use causal reasoning
 Causal reasoning tries to establish the relationship between causes and effects.
 two guidelines:
 to avoid the fallacy of false cause.
 post hoc, ergo propter hoc (after this, therefore because of this):
to assume that because one event comes after another, the first
event must necessarily be the cause of the second.
 (eg. The Cold War was caused by the U.S decision to drop the
atomic bomb at Hiroshima and Nagasaki at the end of World War II.
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to avoid the fallacy of assuming that events have only one cause.
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 to use analogical reasoning
 Analogical reasoning compares two similar cases to draw the conclusion that
what is true in one case will also be true in the other.
 You may claim that your policy will work because it has worked in
like circumstances elsewhere. (e.g. restricting the ownership of
guns will control the crime and murder rates in America)
 Pros: The experience of foreign countries suggest our policy will
work. In England, guns are tightly regulated; even the police are
unarmed, and the murder rate is trivial by American standards. In
Japan, the ownership of weapons is severely restricted, and handguns are completely prohibited. Japan is an almost gun-free
country, and its crime rate is even lower than England’s. On the
basis of these comparisons, we can conclude that restricting the
ownership of guns will control the crime and murder rates in
America.
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 Cons: Advocates of gun control point to foreign countries to prove
their case. They often cite England, which has strict gun control
laws and little violent crime. But the key to low personal violence
in England—and other foreign countries—is not gun control laws
but the generally peaceful character of the people. For example,
Switzerland has a militia system; 600,000 assault rifles each with
two magazines of ammunition are sitting at this moment in Swiss
homes.Yet Switzerland’s murder rate is only 15 percent of ours. In
other words, cultural factors are much more important than gun
control when it comes to violent crime.
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 to make sure that two cases being compared are essentially alike, otherwise
the analogy is invalid
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 to guard against logical fallacies in presentations
 three fallacies mentioned: hasty generalization; false cause; invalid analogy
 five additional ones:
 a. the red herring（红鲱鱼） fallacy（转移话题）: A
fallacy that introduces an irrelevant issue to divert attention
from the subject under discussion.
 b. the ad hominem fallacy（人身攻击）: Attacking the
person who presents an issue rather than dealing logically
with the issue itself.
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c. The either-or fallacy（虚假两分）：Stating that only two alternatives exist when in fact there are more than
two.
d. Bandwagon（诉诸公众）: An argument saying, in effect, "Everyone's doing or saying or thinking this, so you
should too."
e. Slippery Slope: The assumption that if one thing is allowed, it will be the first step in a downward spiral.
f. Non Sequitur（推论失效）: A statement that does not follow logically from what has just been said; in
other words, a conclusion that does not follow from the premises.
g. Equivocation（词语歧义）: An assertion that falsely relies on the use of a term in two different senses.
h. Oversimplification: A statement or argument that leaves out relevant considerations about an issue.
i. Begging the Question（窃取论题）: An assertion that restates the point just made. Such an assertion is
circular in that it draws as a conclusion a point stated in the premise.
To say that we should help the region’s democratic movement begs the question of whether it really is democratic.
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V. emotional appeal
A. “when persuasion is the end, passion also must be engaged” George Campbell
B. three ways
1. emotionally charged language
2. vivid examples
3. to speak with sincerity and conviction