1. SPEECH110 C.ShoreFall 2015 East San Gabriel Valley, ROP
Chapter 8 REASONING
SPEECH110
C.ShoreFall 2015
East San Gabriel Valley, ROP

2. Salvador Dali

3. Learning Objectives
8.1: Explain the nature of rhetorical proof in public speaking and identify its three components.
8.2: Define what a fallacy is and identify some general fallacies.
8.3: Describe six basic patterns of reasoning and fallacies that correspond to particular patterns of reasoning.
8.4: Explore how to avoid errors in reasoning.

4. Reasoning Overview 2 types of statements Objective Subjective
Quantitative
Mathematical
Subjective
Qualitative
Belief v. value
Judgment

5. 8.1: Proof, Support, and Reasoning
Components of Proof
Claims
What you want audience to accept
Supporting material
Evidence for claim
Reasoning (Inference)
Mental leap made to connect SM to C

6. The Toulmin Model Claim Evidence Warrant
A statement that a speaker asks listeners to accept and that the speaker tries to prove.
Evidence
Grounds
Proof, research, data, etc.
Where the warrant comes from
Warrant
Answers the “why?” question
Can be more than one
Because statement that comes from scholar telling you the claim is true

7. 8.1: Proof, Support, and Reasoning
Rhetorical Proof
proof establishing through intersection between the speaker and the listeners; provides support for a conclusion but not assurance that is true.
Interplay between audience and speaker with supporting material
Justifies claims, but not necessarily make it correct
Supporting materials function to support the claims/conclusions
Ask whether all statements marked by Roman numerals in outline, taken together, provide basis for inferring central claim

8. Types of Reasoning Reasoning through Example Reasoning through Analogy
Reasoning through Sign
Reasoning through Cause
Reasoning through Testimony
Reasoning through Narrative

9. Proof and the audience
Audience as the overriding factor in supporting a claim and validity
(true: however audiences may be persuaded by outside noise)
the preemies’ don’t have to be true
all men are moral, Socrates is a man therefore Socrates is moral
Audience diversity influences convincing force of the message, despite validity
Reasonability: the ability of the audience to engage in the arguments that are presented; critically reflect.

10. 8.2: Fallacies
An inference that appears to be sound but on inspection contains a significant flaw.
Fallacy of composition
Fallacy of division
Common cause
Post hoc
Red herring
Ad hominem

11. 8.3: Example Specific instances to illustrate more general claims
Types:
Individual vs. Aggregate (p182)
Representatives vs. Group
Factual vs. Hypothetical (p183)
Real vs. Make believe
Brief vs. Extended (p183)
Lists vs. Plotted/Lengthy
Weaknesses
Fallacy of composition – What is true of the part is automatically true of the whole.
Fallacy of division – What is true of the whole, is true of the part.

12. 8.3: Analogy
Analogy: comparison of people, places, things, events, or more abstract relationships/emotions.
Types:
Literal – direct, like
Figurative – relationships, unlike

13. 8.3: Signs Sign: Something that stands for something else Types
Physical Observation
Regarding something that can be observed as a sign of something cannot
Statistical Index
A statistical measure that is taken as a sign of an abstraction
Institutional Regularity (norms & conventions)
A sign relationship that results from norm or social convention

14. 8.3: Cause
Causal Inference: Influence of one thing on the other (Cause & Effect)
Types
Prediction
Assignment of responsibility
Seeking out the cause
Explanation
Steps to a goal
Fallacies
Common Cause: Assuming that one thing causes another when in fact a third factor really is the cause of both
Post hoc: Assuming that because one event occurred before another, the first is necessarily the cause of the second

15. 8.3: Testimony Relies on other people for supporting materials Types
Fact vs. Opinion
Expert vs. Lay Testimony
Testimony from a person who is generally recognized as an authority on a particular subject vs. testimony from a person who is not an expert
Quoted vs. Paraphrased
Pontificating
Offering judgments without providing any basis for them (not giving a reason)

16. 8.3: Narrative
Broad or abstract ideas made personal and particularized
Types
Sequence of episodes (plots)
Resolution of conflict
Limited identification; only certain people will understand. No visible climax or story line from A->B
Resonance: the quality if striking a response chord with listeners, causing them to identify with what one is saying
Fallacy
Red Herring: straying from the original claim; distracted from the intended focus/argument
Ad hominem: personal attacks

17. 8.4: Avoiding Errors in Reasoning
Six General Tests of Inference
Does the claim follow the support?
Does the claim promote knowledge?
Is the claim relevant?
Is the language clear?
Are probability and certainty distinguished?
Are speaker’s emotions appropriate?

18. Take Away
8.1: Explain the nature of rhetorical proof in public speaking and identify its three components.
Provides sound arguments for thesis
Claim, Supporting material, reasoning (Toulmin model)
8.2: Define what a fallacy is and identify some general fallacies.
Illogical lines of reason
8.3: Describe six basic patterns of reasoning and fallacies that correspond to particular patterns of reasoning.
Example, Analogy, sign, cause, testimony, narrative
8.4: Explore how to avoid errors in reasoning.
Ask 6 specific questions for each inference to determine whether the reasoning seems sound