1. Logic, Reasoning, and fallacy
Rhetoric 1030
Ian Faith
University of Iowa

2. Attendance Question:
Something on your “Bucket List”?

3. Upcoming Due Dates
You will receive feedback on your Project 1 Rough Draft this week
Revise seriously—recall Lamott’s “Shitty First Drafts”
Final Draft Due Date Moved to Friday, 2/19 to the Course Blog. Comment on your submission on the blog in a reflective letter (approximately 1 page) detailing what you think you did well and what you would like to improve on.
By Sunday, 2/21 read and comment on at least two of your peers’ Projects. Give thoughtful feedback that will help them further develop for the next Project.
Reminder: Project 2 Topic proposal due to me by Friday, 2/19.

4. Last Week: Argument by character Improving Credibility
Use of pathetic appeals and the Fables (Logical, Pathetic, and Ethical)
Mythos and the importance of representation

5. This Week: Logical reasoning and logical fallacies
Establishing a sound argument and finding failings in others’
In class analysis
Scavenger Hunt!

6. Why is logical reasoning and critical thinking important?
Regardless of form and content, a claim must be supported by evidence that is unaffected by other variables, and must be confirmed by multiple people (triangulation) in other contexts (replicable).
In other words, even if you aren’t familiar with the subject matter, it doesn’t mean you can think critically about the way in which the argument is structured to convince you of something.

7. Before we discuss logic, how is it that we “know” things?
Colbert Report Clip
4 main sources of human knowledge:
1) Empiricism—Direct Observation
2) Logic--reasoning
3) Authority—Parents, elders, government, religion
4) Intuition—your gut feeling that something seems believable or not

9. Two main types of Reasoning: Induction and Deduction
Comes from Latin, in (prep. Into, toward) or de (prep. Away from, down from) ducere (to lead, to draw)

10. Inductive Reasoning
Induction is based on empirical observations and builds towards broader contexts.
Reasons from specific instances to more general principles.
Championed by Sir Francis Bacon in the early 17th Century. Scientifically, induction means making many observations under controlled conditions and arriving at a general statement of how things are—leads to laws, and eventually theories. However, it requires a constant cycle of challenges, tests, and revisions.
Can a theory ever be proven?

11. Inductive Methods:
Case Studies (Gives a wealth of data on a small sample size)
Paradoxical Incidents
Outliers (How people in extreme circumstances have gotten to where they are)
Serendipity
What are the benefits and shortcomings of Induction?

12. Inductive Problems:
How do you know when you’ve made enough observations? Generalizable?
How do you know you’ve controlled for all variables? Third variable accounts for differences? (E.G. Violent Crime and Ice Cream consumption)
Positive test bias/confirmation bias (E.g. BYU Facilitated Communication)
Self-fulfilling prophecy (Treating people with an expectation, they meet the expectation because of perceived pressure, and their behavior confirms your expectations)
Falsification/Negative test bias

13. Deductive Reasoning
Reasons from general principles to specific instances
In science, usually a theory, law, or generally accepted outcome is used to predict (hypothesize) and then those predictions are tested against specific observations.
Seeks to test generally accepted ideas across a range of contexts.

15. Deductive Techniques
Analogy and metaphor (e.g. thermostat used to explain self-regulation, computer used to explain the brain)
Models and statistics
Hypothetico-Deductive Method: Anticipate consequences from a set of assumptions, e.g. Conditionals: If X, then Y.
Accounting for conflicting results and exceptions
What are the benefits and shortcomings of Deduction?

16. Deductive Problems
Confirmation Bias (Brain size and the skulls of indigenous populations)
Outliers often left out
If the assumptions are wrong, the conclusion will be wrong.
Example: A=B, B=C, therefore, A=C
Example of Deductive failing: Violent criminals are incarcerated. Most incarcerated are African American men. Therefore, most African American men are violent criminals. Here, systemic racism doesn’t factor into the reasoning, and the assumption leads to a faulty conclusion.

17. Group Discussion:
Which type of reasoning (deductive or inductive) do you think is more valuable? Why?
Is there a way to integrate both inductive and deductive reasoning?

18. What is a Logical Fallacy?
Fallacies are failures in logical reasoning wherein the claim is not supported by clear evidence. These happen far more frequently than one would think.
Fallacies are dangerous when they are believed as true, or even worse, motivate people to action.
In science, Type I and Type II errors.
Type I: Null Hypothesis is true and the researcher rejects it. (E.g. A medication is not effective, but the researcher concludes it is.)
Type II: Null Hypothesis is false and the researcher does not reject it. (E.g. A medication is actually effective and the researcher concludes it isn’t.)

19. Common Fallacies
Appeal to Emotion (Pathetic Fable): In place of a compelling argument, the speaker manipulates the audience’s emotions. Ex: Scare tactics. More recently, xenophobia, Islamophobia. trump-mexico-comments-nbc-universal-video
Appeal to Authority (Ethical Fable): Assuming that because the speaker is an expert in a given field, their argument must be true.
False Authority (A variant of the Ethical Fable): Assuming that because the speaker is an authority in another area they must be credible, and therefore their argument must be true. (E.g. Bruce Harreld)
Appeal to Popularity: Assuming that because an idea is popular it therefore must be true.

20. Common Fallacies
False Comparison: A Failure to equate two things—this happens in false analogies or metaphors. Ex: Napoleon Bonaparte’s height.
Straw Man: Simplifying your opponent’s argument to make it easier to attack.
Hasty Generalization: Drawing conclusions from limited amounts of data that are not representative. E.G. MMPI
Ignorance Fallacy: Assertion that because we cannot prove a claim conclusively that it is false.
Burden of Proof: (Related to Ignorance) Asserting that the burden of proof is not on the person making the claim, but rather that it is the responsibility of others to disprove the claim. (E.g. Betrand Russell’s Teapot).

21. Logical Fallacies
False Choice: Presents only two options or outcomes when there may be more.
Personal Incredulity (Related to Intuition): Because one thinks a concept is hard to understand it must be false. (E.G. evolution deniers)
Moderate Leaning: Assuming that the middle point between two extremes must be correct.
Slippery Slope: A chain reaction line of reasoning where one consequence leads to another without sufficient evidence.

23. Logical Fallacies
Red Herring: Changing the subject rather than answering the question z0RfMBiVdPPoJmj58N
Circular Reasoning: The claim and proof are the same. (E.G. Harreld’s response to how to respect transparency while dealing with public controversy.) VdPPoJmj58N&index=4
False Cause: (Post hoc ergo propter hoc) Assumes that because one event happened after another, one caused the other. (E.G. ”My son developed autism after he received a vaccine. Therefore, vaccines cause autism”)
**Correlation does not equal causation.
Ad Hominem (Toward the person): Attacks the opponents person or character rather than responding to the argument.

25. So Why Do People Use Them?
In a speaking context, they can be powerfully effective. In writing, people have more time to scrutinize your ideas.
Do you think it is ethically problematic to knowingly use a fallacy to persuade?
Final Fallacy: The Fallacy Fallacy– Just because logical fallacies exist in an argument doesn’t mean that the conclusion is still wrong. Have you ever answered a math question correctly despite your work to get to that point being wrong?
Recognizing rhetorical fallacies is effective in responding to other positions, but also helps you refine your own ideas.

26. Scavenger Hunt!