Mastering Critical Thinking: A Guide to Sound Reasoning

1. Chapter 16 Thinking and Speaking Critically

2. Thinking and Speaking Critically Critical Thinking • The process of making sound inferences based on accurate evidence and valid reasoning Pseudoreasoning • An argument that appears sound at first glance but contains afallacy of reasoning that renders it unsound

3. Arguments • Verbal aggressiveness • attacking the self-concept of people who disagree with you about controversial claims • Argumentativeness • arguing for and against the positions taken on controversial claims • constructive argumentativeness is the best approach for the public speaker

4. Toulmin’s Model of Reasoning Grounds = evidence

5. Toulmin’s Model of Reasoning Claim = the point the arguer is trying to prove

6. Toulmin’s Model of Reasoning Warrant = links grounds and claim

7. Toulmin’s Model of Reasoning Backing = Support for the warrant

8. Toulmin’s Model of Reasoning Qualifier = Degree of certainty of the argument

9. Toulmin’s Model of Reasoning Rebuttal = Reasons that refute the argument

10. Example using Toulmin Model

11. What is a Fallacy? An argument in which the reasons advanced for a claim fail to warrant acceptance of the claim

12. Fallacies of Claims • Red herring • an irrelevant issue introduced into a controversy to divert attention from the real controversy • Arguing in a circle • the use of a claim to prove its own truth

13. Fallacies of Grounds • Unsupported assertion • the absence of any argument at all • Distorted evidence • significant omission or change in the grounds altering the original intent • Isolated examples • non-typical or non-representative example • Misused statistics • poor sampling, lack of significant differences, misuse of average, misuse of percentages

14. Fallacies of Warrants & Backing • Authority warrant • halo effect • because you like or respect a person, you tend to believe whatever he or she says • ad hominem • attack against the person, not the argument

15. Fallacies of Warrants & Backing • Generalization warrant • hasty generalization • uses specific instances to reach general conclusions • stereotyping • assumes that what is true of a larger class is necessarily true of particular members of that class • false dilemma • implies there are only two choices

16. Figure 15.3 Argument establishing a generalization

17. Figure 15.4 Argument applying a generalization

18. Fallacies of Warrants & Backing • Comparison (analogy) warrant • claims that two cases that are similar in some known respects are also similar in some unknown respects • Causal warrant • post hoc, ergo propter hoc • assumes that because one event preceded another, the first event must be the cause of the second event • slippery slope • assumes that just because one event occurs, it will automatically lead to a series of undesirable events

19. Fallacies of Warrants & Backing • Sign warrant • the presence of an observed phenomenon is used to indicate the presence of an unobserved phenomenon • fallacy of mistaking correlation for cause: just because two things are related doesn’t mean one caused the other.

20. Fallacies of Qualifiers • Loaded language • language that has strong emotional connotations • Hyperbole • an exaggeration of a claim

21. Fallacies of Rebuttal • Straw person • refuting a claim by misstating the argument being refuted • Ignoring the issue • failing to refute the claim being made by the other side

22. Non Sequitur A non sequitur is an argument that does not follow from its premises