rhetoric and logic and argumentation

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Rhetoric, Logic, and Argumentation

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Rhetoric, Logic, Argumentation, Fallacies

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Page 1: Rhetoric and logic and argumentation

Rhetoric, Logic, and Argumentation

Page 2: Rhetoric and logic and argumentation

What is Rhetoric? -the art that humans use to process all the messages we send and

receive

Rhetorical Choices• -what a writer uses to get the meaning across

We focus on two things

I. Analyzing all the language choices that are used to establish the text's meaning,

purpose, and effectiveness

II. Examining the features of the text that establish rhetoric.

Page 3: Rhetoric and logic and argumentation

How to be skilled at Rhetoric

a. excellent writing skillsb. read criticallyc. able to examine a situation and

determine what has already been said , what remains unresolved,

and what you can say to continue the conversation or persuade readers to take action.

Page 4: Rhetoric and logic and argumentation

The RhetoricalTriangle

The 3 rhetoricalappeals

Page 5: Rhetoric and logic and argumentation

Appeal to Ethos: moral character•In an appeal to ethos the speaker (rhetor)

emphasizes the strength of their own moral character and experience in order to establish personal credibility.

Page 6: Rhetoric and logic and argumentation

The Rhetor• The rhetor creates a persona-a mask-the character that the

audience perceives behind the text• is based in part on who the rhetor presumes the audience

to be and in part on what he or she • knows and believes about the subject of the text: what

evidence or proof are the most • compelling and persuasive?•

Members of the audience, hold some beliefs, based on their background knowledge and experiences,

• about the rhetor and the subject and they tap into these beliefs as they listen. Also, the audience,

• uses their ability to reason-and they are persuaded by the strength of the evidence presented.

Page 7: Rhetoric and logic and argumentation

Appeal to Pathos: emotion

•An appeal to pathos attempts to elicit an emotional response from the audience.

Page 8: Rhetoric and logic and argumentation

Appeal to Logos: reason, logic, words.•An appeal to logos relies on the use of

rational analysis and persuasive language.

Page 9: Rhetoric and logic and argumentation

QUIZ: logos, pathos, rhetoric, audience, ethos, message, speaker

• 1. Related to the audience’s feelings• 2. “The art of ruling the minds of men.”• 3. Emphaiszes reason and proof.• 4. The individual (s) on the receiving end of the communication.• 5. The individual presenting the argument in speech, writing, or another

medium.• 6. The ideas being communicated.• 7. Emphasizes the speaker’s/rhetor’s character

Page 10: Rhetoric and logic and argumentation

Cognitive Bias

•Express a hardwired preference for certain flawed patterns

•Because you think means you already have bias▫-your audience is already biased

•Don’t believe everything you think▫Generally see the world as better▫See others as worse▫See patterns where there are none▫Wired to block out people who oppose us

Page 11: Rhetoric and logic and argumentation

Gambler’s Fallacy, Confirmation Bias, Illusory Superiority, bandwagon Effect, Halo Effect, Wishful Thinking, Framing Bias, Clustering Illusion, Self-Serving Bias

• 1. I’ve found at least 30 articles that confirm my idea that some people have extrasensory perception. I’ve also seen reports that disagree, but I have not read any of them.

• 2. I don’t think anyone actually has ESP; everyone I know says that the whole consent is a myth.

• 3. I think some people do have psychic abilities; I would love to think that it’s possible to predict the future.

• 4. Some people can foresee the future, but I don’t think that people can have psychic abilities.

• 5. I’ve notices that every time I think about my best friend, Jessica, she calls me. That’s why I think Jessica has ESP.

• 6. When I called the psychic

Page 12: Rhetoric and logic and argumentation

Deductive vs Inductive Arguments •Deductive

▫1. propose a set of principles▫2. form a conclusion by making a logical

inference from these principles▫3. the conclusion is a logical consequence of

the premises

▫1. All teachers assign homework.▫2. Mrs. Martin is a teacher.▫3. Therefore, Mrs. Martin assigns homework.

Page 13: Rhetoric and logic and argumentation

Syllogism-a deductive argument composed of two premises (major and minor) and a conclusion

•Major Premise: 1. All men are mortal.•Minor Premise: 2. Socrates is a man.•Conclusion: 3. Therefore, Socrates is a

mortal.

Page 14: Rhetoric and logic and argumentation

•Inductive-do not prove that a certain conclusion must be true. They prove that the conclusion is PROBABLY true.

•1. All the students I know hate homework.•2. Cynthia is a student.•3. Therefore, Cynthia probably hates

homework.

Page 15: Rhetoric and logic and argumentation

Deductive Inductive

• 1. All feathered animals are birds.

• 2. Chicken Little has feathers.

• 3. Therefore, Chicken Little is a bird.

• Chicken Little is a bird.• Most birds eat insects.• Therefore, Chicken Little

probably eats insects.

Page 16: Rhetoric and logic and argumentation

Valid-structure is correctSound-the statements must be true and the structure must be correct

• 1. All bananas are purple.• 2. Socrates is a banana.• 3. Therefore, Socrates is

purple.

• 1. There are 12 inches in a foot.

• 2. There are 3 feet in a yard.

• 3. Therefore, there are 36 inches in a yard.

Page 17: Rhetoric and logic and argumentation

Logical Fallacies

•Fallacy means error•Logical fallacy is a mistake in reasoning

Page 18: Rhetoric and logic and argumentation

Non Sequitur

•It does not follow

•1. All aardvarks are mammals.•2. All mammals are animals.•3. Therefore, all animals are aardvarks.

Page 19: Rhetoric and logic and argumentation

Non Causa Pro Causa “non cause for cause”

•The fallacy of mistaken causation.•These arguments mistake mere

coincidence or correlation for causation.

•My grandmother lived to the age of 98.•My grandmother ate chocolate every day.•My grandmother lived to the age of 98

because she ate chocolate every day.

Page 20: Rhetoric and logic and argumentation

Cum Hoc, Ergo Propter hoc “With

this, therefore because of this”

•The speaker assumes there is a causal relationship between two factors simply because they occur at the same time

•Scientists confirm link between ADD and cell phones▫ Studies have shown that since the use of cell phones has

become more widespread worldwide, diagnoses of ADD have increases dramatically. These findings seem to suggest that the radiation emitted by cell phones may cause ADD in some users.

Page 21: Rhetoric and logic and argumentation

Post Hoc, Ergo Propter Hoc “after

this, therefore because of this”

•The speaker attempts to argue that one thing has caused another using only the chronological sequence of evens as evidence .

•The event that happens first is assumed to have caused the events that follows.▫The Society for a Bread-Free Nation claims that

more than 90 percent of violent crimes are committed within 24 hours after the perpetrator has eaten bread. These findings seem to suggest that consuming bread inspires violent behavior.

Page 22: Rhetoric and logic and argumentation

Hasty Generalizations

•The speaker makes a weak analogy between the part and the whole, but the part does not truly exemplify the whole.

•Chester is a cat.•Chester has no tail.•Therefore, cats have no tails.

Page 23: Rhetoric and logic and argumentation

Stereo-Types

•They are all the same to me!•Is a widely accepted, simplistic view of a

people who belong to a given group.

•All politicians I have known lie.•All politicians are exactly like the

politicians I know.•Therefore, all politicians are liars.

Page 24: Rhetoric and logic and argumentation

Loaded Questions

•It is a fallacy of interrogation•This type of fallacy occurs in the form of a

question•They are loaded with assumptions.

•When was the last time you did drugs?•Have you stopped beating your wife?•Why do gun owners like violence?

Page 25: Rhetoric and logic and argumentation

Red Herring

•Arguments that divert attention from the true issues of a debate by emphasizing irrelevant information.

Page 26: Rhetoric and logic and argumentation

Argument from Authority

•Four out of five experts recommend it.

•The US Surgeon General uses a PC.•Therefore, PCs are better than Macs.

Page 27: Rhetoric and logic and argumentation

Ad Hominem• Meant to divert attention from the legitimate issues of the

debate.• Argument “against the man”• The speaker suggests that an opponent's argument should

be rejected on the basis of some quality of the speaker that is not logically related to the credibility of his or her argument.

• A. my research demonstrates that using pesticides in the home increases the risk of cancer.

• B. Have you had cancer?• A. No.• B. Then you’re in no position to know whether pesticides

cause cancer.

Page 28: Rhetoric and logic and argumentation

Guilt by Association

•The speaker attempts to malign an opponent by associating him or her with a negative concept.

•The fallacy is based on the false notion that if an individual can be linked in any way to something offensive, it is fair to equate

Page 29: Rhetoric and logic and argumentation

Straw Man• These arguments are a diversionary tactic• The speaker avoids addressing an opponent’s argument directly by

creating and attacking a “dummy” argument that does not accurately represent the opponent’s stance.

• Whenever a speaker describes an opponent’s argument in a dishonest way, instead choosing to represent a distorted, extremist, or simply absurd version of the argument.

• The Senator from Vermont has suggested that we dismantle our North Atlantic Radar System, now that the Soviet union is no long a threat. I don’t understand why he would want the United States to be defenseless.

Page 30: Rhetoric and logic and argumentation

Emotional Appeal

•Speaker attempts to persuade an audience through emotional manipulation.

•You should eat everything on your plate because there are starving children in Africa.

•If you don’t donate your kidney, you are murdering someone.