Notes from March 22 and 24th!
Methods of Persuasion
do I turn my evidence into powerful arguments? How do I avoid fallacies?
Logos: Research and Reasoning and Pulling it all
(Begin with review)
Three Types of
Are linked to the three modes of
persuasion identified by
(examples and stories bring this forth)
(statistics focus on this aspect)
(testimony can contribute to perception of your ethos)
process of drawing a conclusion on the basis of evidence.
Evidence and Reasoning
to follow your argument and understand WHY something is a problem and
advocate a particular position.
that you’ve taken the time to think through your position.
Identify the flaw (or flaws) in the use of supporting materials
of the following statements:
survey last month of 470 members of the Sierra Club, 98 percent of
interviewed opposed drilling for oil in the Alaskan wilderness.
the American people oppose such drilling.
of one expert, “Mainstream medical care is not meeting the needs of
Americans. I encourage people to pursue alternative treatments such as
acupuncture, chiropractic, and massage therapy.”
compiled by the National Education Association show that the median
teachers in our state is $48,835. This shows that teachers average
$49,000 a year in salary.
survey conducted for Verizon Wireless,
prefer Verizon’s cellular service to that
of Cingular, Nextel, or Sprint PCS.
reason insurance companies should charge higher rates for drivers under
of 25. All my friends drive a lot and almost none of them have been in
noted in a recent interview, the United States needs to change its foreign policy in the Middle East. Otherwise, Penn said, it will be impossible
about lasting peace in the region.
New York Times Almanac, San Francisco has the highest per capita
income of any U.S. city—$57,414. The lowest per capita annual income
McAllen-Edinburg-Mission, Texas, at $13,344. The average per capita annual
income for all U.S. metropolitan areas is $31,333.
Sample Speech: We watched the self defense speech that is at the
end of chapter 16.
Reasoning Process: Deduction and Induction.
Deduction refers to arguments that run from general to specific;
are characterized by necessity.
Induction refers to arguments that run from specific to general; they
are characterized by an inductive leap.
Classic form of Deduction: the syllogism
The U.S. Constitution guarantees citizens the right to
2. More Typical form of Deduction is called the Enthymeme. It
like a syllogism but one of the premises is "assumed" rather than
Its strength comes, so some critics argue, from the belief that if the
audience supplies the missing premise, then they participate in their
The U.S. Constitution guarantees women the right to vote.
Consider: what do you have to believe for these arguments to make
- She's a girl; she can't throw the ball.
- [assumes the listener will supply the principle that "girls
- He's a man, of course he wouldn't stop to ask directions.
- [assumes he listener will supply the principle that "men don't
Our text calls these arguments from principle.
- Gun registration will let the government know where the guns are,
we support gun registration we are helping the government ban guns and
take them away.
- [Assumes the audience will supply the principle: "If the
where guns are, they will eventually ban them and come take them away."]
Self-Defense speech example
[Here is where we picked up
lecture on Wed. March 24th]
All people who are vulnerable to personal attacks are people who should
take a self-defense course.
[this is the assumed premise]
College students are especially vulnerable to personal attacks.
[this is the premise for which much evidence is presented]
Therefore, college students should take a self-defense course.
Beware the false principle.
Boating and Drinking Plan
My plan is to require boater safety education. My claim is that:
Mandatory boater education will result in safer behaviors on the
What must I believe for that argument to work? That having
about a safety issue will result in safer behaviors.
The major form of Inductive reasoning our text calls argument
- The police say he committed the crime, so he committed the crime.
- starting from principles that only those who already agree with
Otherwise known as generalization arguments.
Generalization in the self-defense speech
- Surveys and studies are often grounded in reasoning from specific
- Neilson ratings
A Generalization in the Boating and Drinking speech
- College students are especially easy targets for crime.
- Evidence from Street Wisdom for Women.
- Alcohol use and crime
- campus areas are often the highest crime districts of their
- Drinking and boating is a serious problem [this is proven by lots
Beware the Hasty Generalization
the example on Fox Lake
Statistics from the National Safety Council
Ranking from the U.S. department of transportation
WI State Center for Health Statistics
the U.S Coast Guard
the National Transportation Safety Board
- In a random poll taken last month of 320 members of the American
of Retired Persons, 96 percent of those interviewed clearly opposed any
major changes in the Social Security system. Clearly, then, the
People oppose such changes. [weak because of bias and so you
generalize to the population as a whole].
- the two people I sat next to in lecture got Bs on their speeches,
but me got a B on the speech.
- “but Mom, everybody else is going to the party!”
Arguments from Analogy: Literal or Figurative
Both are grounded in the concept of similarity
Examples of Literal Analogies
Examples of Weak Analogies
- Socialized medicine works in Canada, so socialized medicine will
- The U.S. got rid of the half-penny in 1857 without causing harms,
we can get rid of the penny without causing harms.
- A self-defense course made me able to defend myself; it will make
to defend yourself.
Figurative Analogies can be useful for framing an argument, but they
- The university shouldn't be able to tell me what classes I have
after all, the store manager doesn't tell me what groceries to buy.
- A ban on all alcohol use in the dorms will work at ISU because
worked at Luther College.
- Banning guns worked in Japan, so it will work here.
- Essentially a simile, but can be useful for framing an argument
- As the tiger needs its claws to provide for its internal needs,
America need its defense in order to meet domestic concerns.
- Malcolm X: An integrated civil rights movement is like strong
diluted with cream; its strength is lost.
The most challenging of the types of reasoning.
We cant see causal relationships, we can only infer them.
Problems of Causal Arguments
Tips for success in causal reasoning.
- “post hoc ergo propter hoc” = “after this therefore because of
- confusing a relationship in time with cause and effect
- seen in superstitions
- seen in “just look what happened after we . . . . “ arguments.
- multiple causation
- rainforest destruction is the cause of global warming
- T.V. is responsible for school gun violence.
- my printer problem caused me to be unable to do my speech
- correlation vs. causation
The textbook also discusses several additional types of fallacies
slippery slope, red herring, Either-Or fallacy, ad hominem, and
Read that discussion for more information.
- use causal chains to help the audience see the causal
- use testimony of experts to support conclusions
Can you identify the kind or reasoning and or the fallacy in the
Once you have tried to answer these on your own you can go
here for answers and discussion.
1. According to a study by the American Medical
men with bald spots have three times the risk of heart attack as men
a full head of hair. Strange as it may seem, it looks as if
is a cause of heart attacks.
2. The U.S. Constitution guarantees all citizens the right to bear
Gun control legislation infringes on the right of citizens to bear
Therefore, gun control legislation is contrary to the Constitution.
3. I don’t see any reason to wear a helmet when I ride a
Everyone bikes without a helmet.
4. It’s ridiculous to worry about protecting America’s
parks against pollution and overuse when innocent people are being
by domestic terrorists.
5. There can be no doubt that the Great Depression was
by Herbert Hoover. He became President in March 1929, and the
market crashed just seven months later.
6. If we allow the school board to spend money remodeling the
next they will want to build a new school and give all the teachers a
raise. Taxes will soar so high that businesses will leave and
there will be no jobs for anyone in this town.
7. Raising a child is like having a pet--you need to feed it, play
it, and everything
will be fine.
8. One nonsmoker, interviewed at a restaurant, said, “I can eat
just fine even though people around me are smoking.” Another,
to a Los Angeles Times survey, said, “I don’t see what all the fuss is
about. My wife has smoked for years and it has never
me.” We can see, then, that secondhand smoke does not cause a
for most nonsmokers.
9. I can’t support Representative Frey’s proposal for campaign
reform. After all, he was kicked out of law school for cheating
10. Our school must either increase tuition or cut back on library
As you prepare your speeches don't forget to go
beyond LOGOS issues to make sure you are using Ethos and Pathos as well.
ETHOS: Building credibility throughout
Pathos: Building Emotional Appeals Throughout your
- Announce your expertise
- in the introduction
- as you cite sources
- Announce your concern
- Build Common Ground with your audience
Deliver your speech fluently, expressively and with conviction
- demonstrate concern for their interests and needs
- use shared principles (values, beliefs, attitudes) to build
- Use emotional language
- concrete terms
- stylistic devices
- Develop vivid examples
- Speak with sincerity and conviction
- Use emotional appeals hand in hand with your evidence and
It is a great idea to watch the sample speeches on your textbook
CD-ROM and to read the sample speeches in the text and workbook to look
for the ways others have used Logos, Ethos and Pathos and also to
review the central concepts of Problem, Plan, Practicality in their
WORKSHOP: On Friday only those students who speak next week
should come with their completed outlines for workshop day.