You know, everybody should read these regularly, just so when you're being an ass, you'll know you are. I hate to see people being asses accidentally, it's like watching them pick their nose. The University of Phoenix Master List of Logical Fallacies 1. Ad hominem or ATTACKING THE PERSON. Attacking the arguer rather than his/her argument. Example: John's objections to capital punishment carry no weight since he is a convicted felon. Note: Saying something negative about someone is not automatically ad hominem. If a person (politician for example) is the issue, then it is not a fallacy to criticize him/her. 2. Ad ignorantium or APPEAL TO IGNORANCE. Arguing on the basis of what is not known and cannot be proven. (Sometimes called the burden of proof fallacy). If you can't prove that something is true then it must be false (and vice versa). Example: You can't prove there isn't a Loch Ness Monster, so there must be one. 3. Ad verecundiam or APPEAL TO AUTHORITY. This fallacy tries to convince the listener by appealing to the reputation of a famous or respected person. Oftentimes it is an authority in one field who is speaking out of his or her field of expertise. Example: Sports stars selling cars or hamburgers. Or, the actor on a TV commercial that says, "I'm not a doctor, but I play one on TV." 4. AFFIRMING THE CONSEQUENT. An invalid form of the conditional argument. In this case, the second premise affirms the consequent of the first premise and the conclusion affirms the antecedent. Example: If he wants to get that job, then he must know Spanish. He knows Spanish, so the job is his. 5. AMPHIBOLY. A fallacy of syntactical ambiguity where the position of words in a sentence or the juxtaposition of two sentences conveys a mistaken idea. This fallacy is like equivocation except that the ambiguity does not result from a shift in meaning of a single word or phrase, but is created by word placement.. Example: Jim said he saw Jenny walk her dog through the window. Ow! She should be reported for animal abuse. 6. APPEAL TO EMOTION. In this fallacy, the arguer uses emotional appeals rather than logical reasons to persuade the listener. The fallacy can appeal to various emotions including pride, pity, fear, hate, vanity, or sympathy. Generally, the issue is oversimplified to the advantage of the arguer. Example: In 1972, there was a widely-printed advertisement printed by the Foulke Fur Co., which was in reaction to the frequent protests against the killing of Alaskan seals for the making of fancy furs. According to the advertisement, clubbing the seals was one of the great conservation stories of our history, a mere exercise in wildlife management, because "biologists believe a healthier colony is a controlled colony." 7. ARGUMENT FROM ANALOGY or FALSE ANALOGY. An unsound form of inductive argument in which an argument relies heavily on a weak analogy to prove its point. Example: This must be a great car, for, like the finest watches in the world, it was made in Switzerland. 8. BEGGING THE QUESTION. An argument in which the conclusion is implied or already assumed in the premises. Also said to be a circular argument. Example: Of course the Bible is the word of God. Why? Because God says so in the Bible. 9. SLIPPERY SLOPE. A line of reasoning that argues against taking a step because it assumes that if you take the first step, you will inevitably follow through to the last. This fallacy uses the valid form of hypothetical syllogism, but uses guesswork for the premises. Example: We can't allow students any voice in decision making on campus; if we do, it won't be long before they are in total control. 10. COMMON BELIEF (Sometimes called the bandwagon fallacy or appeal to popularity). This fallacy is committed when we assert a statement to be true on the evidence that many other people allegedly believe it. Being widely believed is not proof or evidence of the truth. Example: Of course Nixon was guilty in Watergate. Everybody knows that. 11. PAST BELIEF. A form of the COMMON BELIEF fallacy. The same error in reasoning is committed except the claim is for belief or support in the past. Example: We all know women should obey their husbands. After all, marriage vows contained those words for centuries. 12. CONTRARY TO FACT HYPOTHESIS. This fallacy is committed when we state with an unreasonable degree of certainty the results of an event that might have occurred but did not. Example: If President Bush had not gone into the Persian Gulf with military force when he did, Saddam Hussein would control the world's oil from Saudi Arabia today. 13. DENYING THE ANTECEDENT. An invalid form of the conditional argument. In this one, the second premise denies the antecedent of the first premise, and the conclusion denies the consequent. Often mistaken for modus tollens. Example: If she qualifies for a promotion, she must speak English. She doesnt qualify for the promotion, so she must not know how to speak English. 14. DIVISION. This fallacy is committed when we conclude that any part of a particular whole must have a characteristic because the whole has that characteristic. Example: I am sure that Karen plays the piano well, since her family is so musical. 15. COMPOSITION. This fallacy is committed when we conclude that a whole must have a characteristic because some part of it has that characteristic. Example: The Dawson clan must be rolling in money, since Fred Dawson makes a lot from his practice. 16. FALSE DILEMMA (often called the either/or fallacy or false dichotomy). This fallacy assumes that we must choose one of two alternatives instead of allowing for other possibilities; a false form of disjunctive syllogism. Example: America, love it or leave it. (The implication is, since you dont love it the only option is to leave it). 17. EQUIVOCATION. This fallacy is a product of semantic ambiguity. The arguer uses the ambiguous nature of a word or phrase to shift the meaning in such a way as to make the reason offered appear more convincing. Example: We realize that workers are idle during the period of lay-offs. But the government should never subsidize idleness, which has often been condemned as a vice. Therefore, payments to laid off workers are wrong. 18. HASTY GENERALIZATION. A generalization accepted on the support of a sample that is too small or biased to warrant it. Example: All men are rats! Just look at the louse that I married. 19. POST HOC, ERGO PROPTER HOC. (After this, therefore caused by this.) A form of the false cause fallacy in which it is inferred that because one event followed another it is necessarily caused by that event. Example: Mary joined our class and the next week we all did poorly on the quiz. It must be her fault. 20. INCONSISTENCY. A discourse is inconsistent or self-contradicting if it contains, explicitly or implicitly, two assertions that are logically incompatible with each other. Inconsistency can also occur between words and actions. Example: A woman who represents herself as a feminist, yet doesnt believe women should run for Congress. 21. NON SEQUITUR. (It does not follow.) In this fallacy the premises have no direct relationship to the conclusion. This fallacy appears in political speeches and advertising with great frequency. Example: A waterfall in the background and a beautiful girl in the foreground have nothing to do with an automobile's performance. 22. QUESTIONABLE CAUSE. (In Latin: non causa pro causa, not the cause of that). This form of the false cause fallacy occurs when the cause for an occurrence is identified on insufficient evidence. Example: I can't find the checkbook; I am sure that my husband hid it so I couldn't go shopping today. 23. RED HERRING. This fallacy introduces an irrelevant issue into a discussion as a diversionary tactic. It takes people off the issue at hand; it is beside the point. Example: Many people say that engineers need more practice in writing, but I would like to remind them how difficult it is to master all the math and drawing skills that an engineer requires. 24. SLANTING. A form of misrepresentation in which a true statement is made, but made in such a way as to suggest that something is not true or to give a false description through the manipulation of connotation. Example: I can't believe how much money is being poured into the space program (suggesting that 'poured' means heedless and unnecessary spending) 25. STRAW MAN. This fallacy occurs when we misrepresent an opponent's position to make it easier to attack, usually by distorting his or her views to ridiculous extremes. This can also take the form of attacking only the weak premises in an opposing argument while ignoring the strong ones. Example: Those who favor gun-control legislation just want to take all guns away from responsible citizens and put them into the hands of the criminals. 26. TWO WRONGS MAKE A RIGHT. This fallacy is committed when we try to justify an apparently wrong action by charges of a similar wrong. The underlying assumption is that if they do it, then we can do it too and are somehow justified. Example: Supporters of apartheid are often guilty of this error in reasoning. They point to U.S. practices of slavery to justify their system. 27. FAR-FETCHED HYPOTHESIS. A fallacy of inductive reasoning that is committed when we accept a particular hypothesis when a more acceptable hypothesis, or one more strongly based in fact, is available. Example: The African-American church was set afire after the civil rights meeting last night; therefore, it must have been done by the leader and the minister to cast suspicion on the local segregationists.