1. Common Logical Fallacies
Flawed Arguments

2. Logical Fallacies… Flaws in an argument Often subtle
Learning to recognize these will:
Strengthen your own arguments
Help you critique other’s arguments

3. Slippery Slope
The arguer claims that a sort of chain reaction, usually ending in some dire consequence, will take place, but there's really not enough evidence for that assumption. The consequences go beyond what is logical.
-- Animal experimentation reduces our respect for life. If we don't respect life, we are likely to be more and more tolerant of violent acts like war and murder. Soon our society will become a battlefield in which everyone constantly fears for their lives. It will be the end of civilization. To prevent this terrible consequence, we should make animal experimentation illegal right now.
Since animal experimentation has been legal for some time and civilization has not yet ended, it seems particularly clear that this chain of events won't necessarily take place.

4. Misuse of Statistics
 A statistical argument that asserts a falsehood, whether accidental or deliberate.
-- 85% of people who have been struck by lightening own cats. Thus, owning cats increases your likelihood of getting struck by lightning.

5. Hasty Generalization
A generalization based on insufficient or unrepresented evidence based on a limited sample.
-- Mrs. Thomas wears Skechers. Mrs. Stuart wears Skechers. All teachers wear Skechers.

6. Fallacy of Composition
the error of assuming that what is true of a member of a group is true for the group as a whole.
-- The tire is made of rubber; therefore, the whole vehicle is made of rubber.
-- Hydrogen is a gas. Oxygen is a gas. Thus, H2O will be a gas.

7. Fallacy of Division
A fallacy of division is the error in logic that occurs when one reasons that something that is true for a whole must also be true of all or some of its parts.
-- Women in the United States are paid less than men. Therefore, my mom must make less money than my dad.
-- Americans, on average, weigh more than Europeans. So, my European cousin who is visiting in a few weeks is going to be thinner than I am.

8. Non Sequitur (Does Not Follow)
A conclusion that does not follow logically from preceding statements or that is based on irrelevant data.
Mary loves children, so will make an excellent school teacher.

9. False Analogy
The assumption that because two things are alike in some respects, they are alike in others.
Life is like a box of chocolates, you’ll never know what you’ll find.

10. “Either… or” Fallacy False Dilemma
The suggestion that only two alternatives exist when in fact there are more.
Either learn how to program a computer, or you won’t be able to get a decent job after college.
If you don’t attend GHS football games, you have no school spirit.

11. False Cause (Post Hoc, Coincidence vs. Causality)
The assumption that because one event follows another, the first is the cause of the second.
Since Governor Smith took office, unemployment for minorities in the state has decreased by seven percent. Governor Smith should be applauded for reducing unemployment among minorities.
Every time Kenady enters my class fourth period begins; thus, Kenady causes fourth period to occur.

12. Circular Reasoning/ Begging the Question (Unsupported Assertion)
An argument in which the writer, instead of applying evidence simply restates the point in other language. The premise and conclusion are the same.
Students should not be allowed to park in lots now reserved for faculty because those lots should be for faculty only.
The Bible is the word of God because it says so in the Bible.

13. Bandwagon Appeal (Ad Populum)
A claim that an idea should be accepted because a large number of people favor it or believe it to be true.
Everyone knows that smoking marijuana is physically addictive and psychologically harmful.

14. Argument to the Person (Ad Hominem)
An attack on the person proposing an argument rather than on the argument itself.
Senator Jones was a conscientious objector during the Vietnam War, so his proposal to limit military spending has no merit.

15. Straw Man
The arguer sets up a wimpy version of the opponent’s position and tries to score point by knocking it down.
"Feminists want to ban all pornography and punish everyone who reads it! But such harsh measures are surely inappropriate, so the feminists are wrong: porn and its readers should be left in peace."
The feminist argument is made weak by being overstated--in fact, most feminists do not propose an outright "ban" on porn or any punishment for those who merely read it; often, they propose some restrictions on things like child porn, or propose to allow people who are hurt by porn to sue publishers and producers, not readers, for damages.

16. Red Herring
An argument that focuses on an irrelevant issue to detract attention from the real issue.
Reporters are out to get the president, so it’s no wonder we are hearing rumors about these scandals. (The issue is about the president’s honesty.)

17. Appeal to Fear Force and Fear (Ad Baculum)
The ad baculum fallacy is committed whenever the proponent of an argument attempts to persuade the audience to accept the conclusion… by predicting (or causing) unpleasant consequences if it is not accepted.
You ought to vote for Senator Gulch, because if you don’t, I’ll burn your house down.
If you don’t vote for the green new deal, we’ll be under water by 2022.

18. Appeal to Celebrity/ Authority (Ad Verecundiam)
The ad verecundiam fallacy consists of an appeal to irrelevant authority, that is, an ‘authority’ who is not an authority in the field of question (or at least one we have no reason to believe to be such an authority).
Oprah says that she won’t eat beef, therefore you shouldn’t eat beef.

19. Appeal to Pity (Ad Misericordiam)
Ad Misericordiam is an appeal to accept the truth of a conclusion out of pity for the arguer or some third party. Either the arguer (or someone else) is already an object of pity, or they will become one if the conclusion is not accepted.
If I don’t get at least a B in this course my GPA will drop below If that happens I’ll lose my scholarship and have to quit school, so I ought to get a B in this course.

20. Appeal to Ignorance Non-Disproof
One sometimes encounters arguments that some claim should be accepted because they have never been disproved. The move from ‘not disproved’ to ‘proved’ is invalid.
No one has ever shown that it is impossible that the stars rule our lives; therefore, astrology is true.
No one has proven that aliens don’t exist; therefore, they must exist.

21. 1. People have been praying to God for years
1. People have been praying to God for years. No one can prove He doesn't exist. Therefore, He exists.
Appeal to ignorance

22. 2. There are starving children in Africa. Eat your carrots.
Red herring

23. 3. Roosters crow before sunrise
3. Roosters crow before sunrise. Therefore, roosters cause the sun to rise.
Post Hoc

24. 4. If we don't adopt that puppy today, they might put him down
4. If we don't adopt that puppy today, they might put him down. Do you want to be responsible for that?
Appeal to pity

25. The famous celebrity rapper Snoop Dog says that evolution is true
The famous celebrity rapper Snoop Dog says that evolution is true. Therefore, it's true.
Appeal to Authority

26. Hydrogen is not wet. Oxygen is not wet
Hydrogen is not wet. Oxygen is not wet. Therefore, water (H2O) is not wet.
Fallacy of Composition

27. Ad populum

28. Circular reasoning

29. Either/Or

30. Credits
Annenberg Public Policy Center (2008). Monty Python and the Quest for the Perfect Fallacy. Retrieved from Hacker, D. (1999). A Writer’s Reference, 4th ed. New York: Bedford/St. Martins. Mike, H. B. (1999). Language and Logic. Dubuque, Iowa: Kendall/Hunt Publishing, Wheeler, K. (2008). Logical fallacies handlist. Retrieved from