Persuasive Appeals Logos AP LANGUAGE AND COMPOSITION

Logos = Logic  Reason (objective proof) is used to spell out claims that are logically sound and supported by reliable evidence.  Logic can be either deductive, inductive, or both

Premise vs. Conclusion  Ask yourself what you are trying to prove. What is your conclusion?  The statements that give your reasons are your premises.  I am an optimist. It does not seem to be much use being anything else. (Churchill) –“I am an optimist” is the conclusion –“It does not seem to be much use being anything else” is the premise or reason for the conclusion

Premises vs Conclusion  A dog was kept in the stalls, and yet, though someone had been in and fetched out a horse, [the dog] had not barked.... Obviously the... visitor was someone whom the dog knew well. (Sherlock Holmes in “The Adventure of Silver Blaze”  Explicit Premise: the dog didn’t bark  General fact premise: he assumes we know that all dogs bark at strangers  Conclusion: The visitor wasn’t a stranger.

Distinguishing the Difference  What is the author trying to convince you to believe? This is the claim/conclusion  Conclusion indicators: therefore, thus, hence, so, consequently, this shows that  Then ask what reasons the author gives to convince you. These are the premises.  Premise indicators: because, since, given that, for, on the grounds that, this follows from

Premise and Conclusion Practice

Inductive Reasoning  Particular to the general  Generalizations are made on an observed fact (often used in scientific experimentation).  Easiest for the audience to accept because evidence is provided  Example: Every patient suffering from flu that the doctor examined had a fever. Therefore, fever must be a symptom of flu.

Deductive Reasoning - Syllogism  moving from the general belief to the particular  every syllogism contains at least three parts:  a major premise (global assumption)  a minor premise (specific claim)  a conclusion

An example of a syllogism Socrates is mortal all men are mortal (major premise) Socrates is a man (minor premise) (conclusion)

all things mortal all men are mortal men Socrates is a man A visual representation Socrates Socrates is mortal

An example of a syllogism fish are not mammals all mammals have hair fish do not have hair (major premise) (minor premise) (conclusion)

all things with hair all mammals have hair mammals A visual representation fish do not have hair fish fish are not mammals

bad drivers All women are bad drivers. woman Jean is a woman. A visual representation Jean Jean is a bad driver.

Simple Syllogism Practice

What is an enthymeme?  sometimes called a “truncated syllogism”  a syllogism without stating either the major or minor premise (it is implied)  less formal than the syllogism  sometimes more persuasive

An example of an enthymeme We cannot trust this man because he has perjured himself in the past. Enthymemes are often “because” statements.

The syllogism behind this enthymeme… Those who perjure themselves cannot be trusted. This man perjured himself in the past. This man cannot be trusted. (major premise) (minor premise) (conclusion)

Enthymemes are sometimes used to hide the underlying assumption upon which an argument is based. Find it and challenge it. Beware. Think Critically.

What are the unstated assumptions?  I failed that course because the instructor didn’t like me. Assumption: The instructor fails students he doesn’t like.  I’m not surprised he made the team. After all, his father is the superintendent of schools. Assumption: The superintendent gives special favors to his family  If I’d only taken my boss to lunch more often, I could have gotten that raise. Assumption: The boss denies raises to people who don’t take him to lunch very often.

Practice