1. Fallacies The quickest ways to lose arguments

2. Introduction to Logic O Argument: The assertion of a conclusion based on logical premises O Premise: Proposition used as evidence in an argument O Conclusion: Logical result of the relationship between the premises. Conclusions serve as the thesis of the argument. O Syllogism: The simplest sequence of logical premises and conclusions. Developed by Aristotle.

3. Syllogism O Premise 1: All men are mortal. O Premise 2: Socrates is a man. O Conclusion: Therefore, Socrates is mortal. O Reaching logical conclusions depends on the proper analysis of premises. O The goal of a syllogism is to arrange premises so that only one true conclusion is possible. O Logic allows specific conclusions to be drawn from general premises.

4. Syllogism O Logic requires decisive statements in order to work. O For example, the premise that “SOME men are mortal” does not contain enough information to allow a verifiable conclusion. O Logic cannot be based on premises which the audience does not accept.

5. Let’s Practice! O Complete the syllogism: O Premise 1: O Premise 2: O Conclusion: Therefore, the California minimum wage should be increased.

6. Possible Answer O Premise 1: Minimum wage should match the cost of living in society. O Premise 2: The current California minimum wage does not match the cost of living in society. O Conclusion: Therefore, the California minimum wage should be increased.

7. What is a fallacy? O A fallacy is a flaw or an error in an argument

8. Hasty Generalization O Making assumptions about an entire range of people or a range of cases based on an inadequately small sample or one experience O Stereotypes are a common example

9. Missing the Point O The premise supports a conclusion other than the one it’s meant to support O Example: Premise 1: There has been an increase in burglaries in the area. Premise 2: More people are moving into the area. Conclusion: Therefore, the burglaries are caused by and increased number of people moving to the area.

10. False Cause O In Latin, this fallacy is called post hoc. It comes from the phrase post hoc, ergo propter hoc, which means after this because of this O This fallacy presumes that because X preceded Y, X caused Y. O Example: Premise 1: Cell phone usage has increased in the last 20 years. Premise 2: Researchers discovered that incidences of brain cancer have increased in the last 20 years. Conclusion: Therefore, cell phone usage must cause brain cancer.

11. Slippery Slope O Falsely assuming that one thing will inevitably lead to another, and another, and another until we have reached some unavoidable, dire consequence.

12. Weak Analogy O When you compare two things that aren’t really similar

13. Appeal to Authority O When an arguer tries to get people to agree with them by appealing to a supposed authority figure who is not really an expert

14. Appeal to Pity O Attempting to convince someone to do something or agree with them by making them feel sorry O Students are great at using this fallacy!

15. Appeal to Ignorance O This fallacy states that because there is no conclusive evidence, the arguer’s conclusions on the subject should just be accepted. O The lack of evidence is used to support the conclusion O Example: Premise: Not a single report of a UFO has been authenticated. Conclusion: Therefore, UFOs do not exist.

16. Bandwagon O When the arguer tries to convince someone to do something because everyone else (supposedly) does O Example: Premise: An increasing number of people are turning to CrossFit to get in tough with their center. Conclusion: Therefore, CrossFit helps everyone get in touch with their center.

17. Ad Hominem O Attacking the other side instead of their argument.

18. Tu quoque O The arguer points out that the opponent has actually done the thing they are arguing against, concluding that we do not have to listen to the argument

19. Straw Man O The arguer sets up a weaker version of the opponent’s position and seeks to prove that version rather than the position the arguer actually holds O Through misrepresentation, the arguer concludes that the real position has been refuted. O Example: Those who seek to abolish the death penalty are seeking to allow murderers and others who commit heinous crimes to simply get off scot-free with no consequence for their actions

20. Red Herring O The arguer goes off on a tangent midway through the argument, raising a side issue that distracts the audience from the main or original argument

21. False Dichotomy O The arguer sets up the situation so that it looks as though there are only two choices. When the arguer then eliminates one of the choices, it appears as if there’s only one option left—the arguer’s assertion. O Usually a situation is oversimplified and other options are eliminated. O Example: Premise 1: I can’t find my book! Either someone stole it or I never had it. Premise 2: I know I had it. Conclusion: Therefore, someone stole it.

22. Begging the Question O The arguer asks the audience to simply accept the conclusion without providing any real evidence, either through the use of circular reasoning or by ignoring an important (but questionable) assumption that the argument rests on. O Circular reasoning occurs when the premise states the same thing as the conclusion. O This is a harder fallacy to detect/avoid. O Example: Paranormal activity is real because I have experienced what can only be described as paranormal activity. O Example: If such acts weren’t illegal, then they would not be prohibited by the law.

23. Information adapted from O Lecture by Andrea Hernandez—Summer 2015. O Various slideshare presentations on fallacies.