2. Copyright © 2011 Pearson Education, Inc. Thinking Critically

3. Copyright © 2011 Pearson Education, Inc. Slide 1-3 Unit 1A Recognizing the Fallacies

4. 1-A Copyright © 2011 Pearson Education, Inc. Slide 1-4 Definitions Logic is the study of the methods and principles of reasoning. An argument uses a set of facts or assumptions, called premises, to support a conclusion. A fallacy is a deceptive argument—an argument in which the conclusion is not well supported by the premises.

5. 1-A Copyright © 2011 Pearson Education, Inc. Slide 1-5 Fallacy Structures Appeal to PopularityMany people believe p is true; therefore…p is true. False CauseA came before B; therefore…A caused B. Appeal to IgnoranceThere is no proof that p is true; therefore…p is false. Hasty GeneralizationA and B are linked one or a few times; therefore…A causes B (or vice versa).

6. 1-A Copyright © 2011 Pearson Education, Inc. Slide 1-6 Fallacy Structures Limited Choicep is false; therefore…only q can be true. Appeal to Emotionp is associated with a positive emotional response; therefore… p is true. Personal AttackI have a problem with the person or group claiming p; therefore… p is not true. Circular Reasoningp is true. p is restated in different words. (The argument states the conclusion.)

7. 1-A Copyright © 2011 Pearson Education, Inc. Slide 1-7 Fallacy Structures Diversion (Red Herring)p is related to q and I have an argument concerning q; therefore…p is true. Straw ManI have an argument concerning a distorted version of p; therefore…I hope you are fooled into concluding I have an argument concerning the real version of p.

8. 1-A Copyright © 2011 Pearson Education, Inc. Slide 1-8 Examples Determine the fallacy structure of each argument. “Your lack of enthusiasm for astronomy proves that you hate science.” → Limited choice “I don’t support the mayor’s tax plan because he is a bad person.” → Personal attack “This movie sold the most tickets last weekend, so it must be the best movie in the theaters.” → Appeal to popularity