1. Chapter 12 Informal Fallacies II: Assumptions and Induction www.criticalthinking1ce.nelson.com Invitation to Critical Thinking First Canadian Edition Joel Rudinow Vincent E. Barry Mark Letteri

2. © 2008 by Nelson, a division of Thomson Canada Limited 12-2 Overview  Fallacious Assumptions  Fallacies of Inductions

3. © 2008 by Nelson, a division of Thomson Canada Limited 12-3 Fallacious Assumptions Informal fallacy of false dilemma Informal fallacy of false dilemma Loaded questions Loaded questions Informal fallacy of innuendo Informal fallacy of innuendo Informal fallacy of begging the question or circular reasoning Informal fallacy of begging the question or circular reasoning

4. © 2008 by Nelson, a division of Thomson Canada Limited 12-4 Fallacious Assumptions  False dilemma fallacy: a fallacy of underestimating or underrepresenting the number of possible alternatives for a given issue.

5. © 2008 by Nelson, a division of Thomson Canada Limited 12-5 Fallacious Assumptions  Loaded Questions: a question is so worded that you can’t answer it without also granting a particular answer to some other question.

6. © 2008 by Nelson, a division of Thomson Canada Limited 12-6 Fallacious Assumptions  Innuendo: a fallacy in which a judgment, usually derogatory, is implied by hinting.

7. © 2008 by Nelson, a division of Thomson Canada Limited 12-7 Fallacious Assumptions  Begging the question or circular reasoning: a fallacy of assuming or presupposing one's conclusion as a premise.

8. © 2008 by Nelson, a division of Thomson Canada Limited 12-8 Fallacies of Induction Generalizations  Small sample  Unrepresentative sample  Suppressed evidence  Bad baseline Analogies  False analogies  Arguing ad ignorantiam  Invincible ignorance Hypothetical and causal reasoning  Only game in town  Jumping from correlation to cause  Post hoc ergo propter hoc  Overlooking a common cause  Oversimplification  Slippery slope  Gambler’s fallacy

9. © 2008 by Nelson, a division of Thomson Canada Limited 12-9 Fallacies of Induction: Generalizations Small sample: a fallacy of statistical inference consisting of overestimating the statistical significance of evidence drawn from a small number of cases.

10. © 2008 by Nelson, a division of Thomson Canada Limited 12-10 Fallacies of Induction: Generalizations Unrepresentative sample: a fallacy of statistical inference involving overestimating the statistical significance of evidence drawn from a sample of a particular kind.

11. © 2008 by Nelson, a division of Thomson Canada Limited 12-11 Fallacies of Induction: Generalizations Suppressed evidence: persuasive strategy consisting of covering up available evidence that conflicts with an intended conclusion.

12. © 2008 by Nelson, a division of Thomson Canada Limited 12-12 Fallacies of Induction: Generalizations Bad baseline: a fallacy of statistical inference based on an inappropriate basis of comparison.

13. © 2008 by Nelson, a division of Thomson Canada Limited 12-13 Fallacies of Induction: Analogies Faulty analogy: An argument based on similarities that are irrelevant to the conclusion.  An argument that glosses over relevant differences.

14. © 2008 by Nelson, a division of Thomson Canada Limited 12-14 Fallacies of Induction: Analogies Arguing ad ignorantiam: a fallacy of inferring a statement from the absence of evidence or lack of proof of its opposite.

15. © 2008 by Nelson, a division of Thomson Canada Limited 12-15 Fallacies of Induction: Analogies Invincible ignorance: fallacy of refusing to give due consideration to evidence that conflicts with what one is already committed to believing.

16. © 2008 by Nelson, a division of Thomson Canada Limited 12-16 Fallacies of Induction: Hypothetical and Causal Reasoning Only game in town: concluding hastily that some explanation or solution holds true simply because one cannot think of a better one.

17. © 2008 by Nelson, a division of Thomson Canada Limited 12-17 Fallacies of Induction: Hypothetical and Causal Reasoning Jumping from correlation to cause: causal fallacy in which an observed statistical correlation is interpreted as showing a causal connection without first having made a reasonable attempt to isolate the cause by controlling the relevant variables experimentally.

18. © 2008 by Nelson, a division of Thomson Canada Limited 12-18 Fallacies of Induction: Hypothetical and Causal Reasoning Post hoc ergo propter hoc: a variety of causal fallacy in which order of events in time is taken to establish a cause and effect relationship.

19. © 2008 by Nelson, a division of Thomson Canada Limited 12-19 Fallacies of Induction: Hypothetical and Causal Reasoning Overlooking a common cause: causal fallacy in which one of two effects of some common cause is taken to cause the other.

20. © 2008 by Nelson, a division of Thomson Canada Limited 12-20 Fallacies of Induction: Hypothetical and Causal Reasoning Causal oversimplification: a variety of causal fallacy in which significant causal factors or variables are overlooked.

21. © 2008 by Nelson, a division of Thomson Canada Limited 12-21 Fallacies of Induction: Hypothetical and Causal Reasoning Gambler’s fallacy: any of a variety of fallacies of inductive reasoning concerning estimating or beating the odds, often based on the use of past outcomes to predict the future outcome of chance events.

22. © 2008 by Nelson, a division of Thomson Canada Limited 12-22 Fallacies of Induction: Hypothetical and Causal Reasoning Slippery slope: a fallacy consisting of objecting to something on the grounds that it will lead, by dubious causal reasoning, to some unacceptable set of consequences.