Logical Reasoning

1. Logical Reasoning • Verbal citations and validity of evidence • Rebuttals • Inductive and deductive reasoning • Cause-and-effect reasoning • Reasoning by generalization • Reasoning by analogy • Reasoning by syllogism

2. Verbal citations • Evidence persuades more powerfully than biased personal statements • Your credibility depends on the listener’s willingness to believe what you are saying • You’ll bolster your image of competence if it becomes clear that you have researched your topic really well. Show your knowledge! • They enable you to avoid plagiarism

3. What needs to be cited? • Direct quotations • Opinions, assertions, or ideas of others, even if they are paraphrased rather than quoted • Statistics • Any non-original visual materials, including graphs, tables and pictures

4. Verbal Citations Make your speech even more credible by citing your evidence. …

5. How do I do this smoothly? • Easy! • “According to Tom Smith, the author of Public Speaking is Fun, most people are nervous about speaking in front of a crowd.” • When citing an internet source, say just enough of the website for credibility. Rather than saying www.newsweek.com just say, “according to Newsweek Online, the January 19, 2012 issue quotes President Obama as saying, …”

6. What sources are credible? • Published books, periodicals and documentaries are viable/credible sources • Using the Internet effectively requires careful research, which reflects credibility. If your sources are not credible, your credibility is compromised. No one cares what “you think”

7. Logical Reasoning • Evaluating Evidence • Refuting the opponent • Cause-and-Effect Reasoning • Generalization • Analogy • Syllogism

8. Who Killed John Jones? Evaluating Evidence: Critical Thinking Practice

9. MURDER!!!! • In 1940, John Jones died after he was struck with a poison dart. • Someone was charged with murder, and the trial lasted for weeks. • Eventually, the jury reached a verdict. • Now, we’ll re-create the murder (with a few changes) and see if the jury was correct.

10. In the area outside the room, at about 10:35 a.m., someone was murdered with a poison dart. Several witnesses were present. Others were nearby. Those witnesses are available for questioning. No witnesses would lie, but the murderer would. The Facts

11. Good questions to ask witnesses: • What did you see? • What did you hear? • Where were you? • Where is the murder weapon? • Is there other evidence? • Are there other witnesses? • Who killed the victim?

12. Evaluating Evidence - PROP • Is there a source for the information? • If no, the information is unsupported and weakened. • If yes, evaluate it: • P – primary or secondary? • R – reason to lie or exaggerate? • O – other evidence to verify this evidence? • P – public or private?

13. P – Primary or secondary source • Primary source is evidence given by a person present at event. It can also be an object that was part of event. • Primary sources are more desired. • Your should look to collect as many primary sources as possible to create an argument. • Collect secondary sources only when primary sources are unavailable.

14. R – Reason to lie/distort • People have reasons to lie • Make themselves or their group look good • To help their own interests (i.e. to make money) • Does the person giving the statement, writing the document, recording the audio, or identifying the object benefit from the truth being distorted, covered up, falsified, sensationalized, or manipulated? • Witnesses with no reason to do the above are more desirable.

15. O – Other evidence • Is there more info that reports the same data? • Witnesses • Statements • Recordings • Evidence • Having other evidence to verify adds strength to your argument.

16. P – Public or private statement • Public if… • The person knew that others would see, hear or read what they said • Private if… • The person stated the information in confidence • Private is judged more accurate because it was probably more likely to reflect the speaker’s true feeling or observations.

17. Bill said he didn’t steal the radio. • The Pilgrims said they would not have survived without the help of friendly Indians, such as Squanto. • Captain John Smith said in 1614 that he generally caught 200-300 cod each day. • William Penn said that his colony, Pennsylvania, was the best colony in North America. • The police found the stolen radio in Emily’s locker. (The evidence is the radio.)

18. Welcome! • Please take out “25…speaker” sheet and Speak-better chart • Which ones did you move? Which moves have the most convincing reasons?

19. The Rebuttal Interlude, 6 steps • REMIND US: “They said …” • Name group • TRANSITION: “But actually …” • YOUR REASON: • EVIDENCE: • Choose to highlight your evidence, crush theirs, or both • ANALYSIS: • Make sure it’s complete • CONCLUSION: • Better every time. Vary!

21. Re-rank!! • Read “25 Skills…” and consider how much you agree with both the entries and the order. • Re-rank them. Cross out the numbers and write in new ones. • Justify at least 10 changes in the margins, with a couple sentences. • Think about which you will bring up for your quick speech: • Skill, old ranking-new ranking claim, evidence?, analysis, rebuttal?, conclusion

22. Think about which you will bring up for your quick speech: • Skill, old ranking-new ranking claim, evidence?, analysis, rebuttal?, conclusion

23. Rebuttal practice • Your group goes to the front. • First person projects sheet, gives speech. • Second person refutes first person, then gives speech. • Third person refutes second, then gives speech. • Fourth person refutes third, then gives speech. • First person refutes fourth person. Finished!

24. Simple Rebuttal Rubric • Name group (besides person)? • Evidence (either theirs, why it’s bad or yours, why it’s good)? • Complete analysis? • Conclusion?

25. Cause & Effect Reasoning

26. Scholars … • Recognize Cause & Effect as being complex • Events often have multiple causes • Try to figure out the most important causes • This is where debate often occurs

27. Key Words • Look for words in the reading like… • “caused”, “led to,” “forced,” “because,” “brought about,” “resulted in,” or “reason for.” • These will cue you to look for a cause & effect relationship.

29. For example… • Laura’s motorcycle will not start (effect), so she decides it must be out of gas (proposed cause).

30. Key Questions • Is there a reasonable connection between the cause and effect? • Might there be other possible causes for this effect? • Might there be important previous causes that led to the proposed cause?

31. Now apply our questions • Laura’s motorcycle will not start (effect), so she decides it must be out of gas (proposed cause). • Is there a reasonable connection between the cause and effect? • Yes. An engine typically needs gasoline to start.

32. Now apply our questions • Laura’s motorcycle will not start (effect), so she decides it must be out of gas (proposed cause). • Might there be other possible causes for this effect? • Yes. The starter might not be functioning, there is a block in the gas line, etc. • Other possible causes have not been eliminated.

33. Now apply our questions • Laura’s motorcycle will not start (effect), so she decides it must be out of gas (proposed cause). • Might there be important previous causes that led to the proposed cause? • Sometimes a previous cause may be more important. • Say there is a hole in the gas tank. Then putting gas in the motorcycle won’t make any difference.

34. Cause-and-Effect Fallacies • Single Cause • Preceding event as cause • Correlation as cause • False scenario

35. Single Cause Fallacy • Any conclusion that a historical event had but one cause is a single cause fallacy. • For example… • Megan married Seth because he is handsome. • George Bush attacked Iraq because of weapons of mass destruction. • There are probably a number of other causes that led to these events. • This does not mean these aren’t the most important causes.

36. Preceding Event Fallacy • This happens when someone assumes that because event B happened after event A, A caused B. • For example… • I washed my car, so naturally it rained. • Since George Bush became President, Mr. Rosemont became a teacher. • To avoid this, the author must explain the connection.

37. Correlation Fallacy • The fallacy occurs when a conclusion is reached that because A and B occurred at the same time, then one caused the other. • For example… • Students who have fewer absences (A) achieve higher grades in school (B). • Students who achieve higher grades in school (B) have fewer absences (A). • You cannot say that one causes another, though you can say there is a correlation, or relationship, between the two.

38. False Scenario • The fallacy uses the argument that if something had happened, then something else would have happened. • For example… • If you hadn’t told on me, I wouldn’t have gotten in trouble. • If the Natives Americans had killed all the colonists at Jamestown, then North America would be filled with only Native Americans. • Try to focus on what actually happened, not what might have happened.

39. Evaluate your reasoning • Is there a reasonable connection between the cause and effect? • Might there be other possible causes for this effect? • Might there be important previous causes that led to the proposed cause?

40. 1. Enroll in the class on turnitin.com 12230953, spartans 2. Open the “CriticalThinking” ppt from attachments 3. Review cause-effect reasoning (slides 25-39) 4. Make sure your paragraph is great! Then mark it up: 5. Underline the cause.Bold the effect. 6. Italicize the rebuttal of potential argument against yours 7. Turn in to turnitin.com

41. Reasoning by Generalization Powerful and dangerous

42. Includes two types • Definitional – By definition is correct or not. • For example, no U.S. senator is under 30 years of age. • Statistical – Important to historical arguments • Argues that what is true for some (a part or sample) of a group (such as wars, women, or songs) will be true in roughly the same way for all the group. • i.e. Megan might argue that since the bite of pizza she took (sample) is cold, the whole pizza (the whole group) is cold.

43. Statistical – Hard Generalizations • Those generalizations that are applied to all or none of a group • The pizza example before or… • i.e. All the apples fell off the of the tree. • Hard Generalizations can be disproved with only one counter example.

44. Statistical – Soft Generalizations • Those that are applied to most (or a few) members of a group. • i.e. Most people remember the Vietnam War. • Is not disproved by one – or even several- contrary cases. • Is weakened as the number of contrary cases builds up. • i.e. Mr. Matheny says he doesn’t remember the Vietnam War. The generalization is not disproved. • Mr. Matheny and every teacher around say they don’t remember the Vietnam War. Now the generalization gets shaky.

45. Increase those odds!!! • Probability of statistical generalizations being correct increase… • … with the size of the sample. • i.e. Mr. Matheny says Mr. Marshall is prompt. How would we be able to know that Mr. Marshall is always prompt?

46. Increase those odds!!! • Probability of statistical generalizations being correct increase… • … with the degree to which a sample represents the whole group. • This is even more important than size in generalizations. • i.e. In the pizza example, the sample is quite small (a single bite from the whole pizza) but very representative. • It’s highly likely that if one part of the pizza is cold, then all of it is cold.

47. Exit polling during elections Men Occupations Racial Groups Ethnic Groups Religious affiliations Regions of the country Special interests Income levels Age groups Women Etc. Voters Sample

48. Generalization Questions • How large is the sample? • The strength of a statistical generalization is improved by a larger-sized sampling. • How representative is the sample? • If you picture the generalization as a little circle and a big circle (see previous slide), the question becomes: Does the little circle have all the same subgroups in the same proportion as the big circle?

49. Review, the questions to improve your generalizations: • Argument by Generalization. Argument by generalization assumes that a number of examples can be applied more generally. This is a form of inductive reasoning, whereby specific instances are translated into more general principles. Any time individual incidents are marshaled to prove overarching claims, argument by generalization is being used. Surveys and public opinion polls are often generalizations of what the larger group thinks based on a small, ideally representative, sample of interviewees. Arguing that the sun will rise tomorrow because it has risen for the last several years every morning is also a generalization about the future based on past events. Testing arguments by generalization can include questions like these: • Are the examples analogous? • Are there enough examples? • Do the examples come from different times, places, and situations? • Are the examples specific enough? • Are there counterexamples?

50. Blondes are dumb? • Blondes are dumb? • Does the stereotype refer only to natural blondes? Does the stereotype only to female, not male blondes? • Reese Witherspoon attended Stanford and won an Oscar. • Hillary Clinton, law degree from Yale • Lisa Kudrow, degree in biology from Vassar • Sharon Stone has a reported IQ of 154 • Kim Campbell, Canada’s first female prime minister, is blonde.