common types of fallacies

Ad Hominem An argument based on the perceived failings of an adversary rather than on the merits of the case; a logical fallacy that involves a personal attack. Ad Misericordiam An argument based on an appeal to the emotions; a logical fallacy that involves an irrelevant or highly exaggerated appeal to pity or sympathy. Also known as argumentum ad misericordiam or appeal to pity or misery. The fallacy fallacy is a logical fallacy that occurs when it is claimed that if an argument contains a logical fallacy, the proposition it was used to support is wrong. A true statement can be defended using false logic, so using false logic to defend an opinion is not proof of the opinion being wrong. This is where one needs to make a clear distinction between "sound", "valid" (including the distinction between scientific validity and logical validity) and "true", instead of taking all of them as synonymous. The fallacy is a special case of denying the antecedent and is a formal fallacy. Amphiboly A fallacy that relies on an ambiguous word or grammatical structure to confuse or mislead an audience. Adjective: amphibolous. appeal to authority A fallacy in which a rhetor seeks to persuade an audience not by giving evidence but by appealing to the respect people have for the famous. e.g. These pills must be safe and effective for reducing. They have been endorsed by Miss X, star of stage, screen, and television. appeal to force A fallacy that relies on force or intimidation (scare tactics) to persuade an audience to accept a proposition or take a particular course of action. e.g. If the Iraqi regime is able to produce, buy, or steal an amount of highly-enriched uranium a little larger than a single softball, it could have a nuclear weapon in less than a year. appeal to humor A fallacy in which a rhetor uses humor to ridicule an opponent and/or direct attention away from the issue at hand. Like name calling, red herring, and straw man, the appeal to humor is a fallacy that manipulates through distraction. e.g. A well-known example is from a debate on evolution when one speaker asked the other: Now, is it on your mother's side or your father's that your ancestors were apes? appeal to ignorance A fallacy based on the assumption that a statement must be true if it cannot be proved false. e.g.There is intelligent life in outer space, for no one has been able to prove that there isn't. appeal to the people An argument (generally considered a logical fallacy) based on widespread opinions, values, or prejudices and often delivered in an emotionally charged way. Also known as argumentum ad populum. e.g. The public buys its opinions as it buys its meat, or takes in its milk, on the principle that it is cheaper to do this than to keep a cow. So it is, but the milk is more likely to be watered." Bandwagon A fallacy based on the assumption that the opinion of the majority is always valid: everyone believes it, so you should too. Also called argumentum ad populum (Latin for "appeal to the people"). begging the question（ circular argument） Begging the question is a fallacy in which the premise of an argument presupposes the truth of its conclusion; in other words, the argument takes for granted what it's supposed to prove. An argument that commits the logical fallacy of assuming what it is attempting to prove. complex question A fallacy in which the answer to a given question presupposes a prior answer to a prior question. a) Have you stopped beating your wife? b) Did John ever give up his bad habits? c) Are you still a heavy drinker? contradictory premises An argument (generally considered a logical fallacy) that draws a conclusion from inconsistent or incompatible premises. Essentially, a proposition is contradictory when it asserts and denies the same thing. e.g. If God can do anything, can He make a stone so heavy that He won’t be able to lift it?' "'Of course,' she replied promptly. "'But if He can do anything, He can lift the stone,' I pointed out. "'Yeah,' she said thoughtfully. 'Well, then I guess He can’t make the stone.' "'But He can do anything,' I reminded her. "She scratched her pretty, empty head. 'I’m all confused,' she admitted. "'Of course you are. Because when the premises of an argument contradict each other, there can be no argument. If there is an irresistible force, there can be no immovable object. If there is an immovable object, there can be no irresistible force. Get it?' dicto simpliciter草率前提 A fallacy in which a general rule is treated as universally true regardless of the circumstances: a sweeping generalization. e.g. 'Exercise is good. Therefore everybody should exercise.' "'I agree,' said Polly earnestly. 'I mean exercise is wonderful. I mean it builds the body and everything.' "'Polly,' I said gently. 'The argument is a fallacy. Exercise is good is an unqualified generalization. For instance, if you have heart disease, exercise is bad, not good. Many people are ordered by their doctors not to exercise. You must qualify the generalization. You must say exercise is usually good, or exercise is good for most people. Otherwise you have committed a Dicto Simpliciter. Do you see?' equivocation A fallacy by which a key word or phrase in an argument is used with more than one meaning. e.g. The sugar industry, for instance, once advertised its product with the claim that "Sugar is an essential component of the body . . . a key material in all sorts of metabolic processes," neglecting the fact that it is glucose (blood sugar) not ordinary table sugar (sucrose) that is the vital nourishment." etymological fallacy The faulty argument that the "true" or "proper" meaning of a word is its oldest or original meaning. Because the meanings of words change over time, a word's contemporary definition can't be established from its origin (or etymology). The best indicator of a word's meaning is its current use, not its derivation. In our own day the etymological fallacy is widely honored, as revealed in countless statements by columnists, in letters to editors, and other public fora, which declare for example that the real meaning of doctor is 'teacher'; or that the verb orient properly means 'to arrange something to face east'; or that gyp 'cheat' is derived from Gypsy (probably), and therefore its use in any context is de facto an ethnic slur; or that decimate correctly means only 'to punish a mutiny or other serious breach of military discipline by killing one soldier in ten. false analogy A fallacy in which an argument is based on misleading, superficial, or implausible comparisons. false analogy is central to jokes whose humour derives from ill-judged comparisons, as in the old joke where a mad scientist builds a rocket to the sun but plans to embark at night to avoid being cremated. Here a false analogy is created between the sun and a light bulb, suggesting that when the sun is not shining it is not 'turned on,' and hence, not hot." "When you find yourself reasoning by analogy, ask yourself two questions: (1) are the basic similarities greater and more significant than the obvious differences? (2) am I over-relying on surface similarities and ignoring more essential differences?" false dilemma 错误屏蔽了其他的结论 A fallacy of oversimplification that offers a limited number of options (usually two) when in reality more options are available. e.g. Either medicine can explain how Ms. X was cured, or it is a miracle. Medicine can't explain how she was cured. Therefore it is a miracle. gambler's fallacy A fallacy in which an inference is drawn on the assumption that a series of chance events will determine the outcome of a subsequent event. Also called the Monte Carlo fallacy, the negative recency effect, or the fallacy of the maturity of chances. misleading vividness A fallacy in which anecdotal evidence (or a single vivid image, report, or experience) is offered as proof--in particular, when a small number of dramatic events are allowed to outweigh a significant amount of statistical evidence that supports an opposing view. e.g. Of course violent crime is up in our schools. don't you remember hearing about the awful shooting in that school last month?" name-calling A fallacy that uses emotionally loaded terms to influence an audience. Name-calling, says J. Vernon Jensen, is "attaching to a person, group, institution, or concept a label with a heavily derogatory connotation. It usually is an incomplete, unfair, and misleading characterization" non sequitur A fallacy in which a conclusion does not follow logically from what preceded it. As illustrated below, non sequiturs are the products of many different kinds of errors in reasoning, including begging the question, false dilemma, ad hominem, the appeal to ignorance, and the straw man argument. We realize that it would be in the best interest of the community and our children to address the issue expeditiously. In order to make this happen, I respectfully request an eight-month payment delay calling for payment of the $10 million obligation on August 31, 2015." paralepsis The rhetorical strategy (and logical fallacy) of emphasizing a point by seeming to pass over it. Also spelled paralipsis. Adjective: paraleptic or paraliptic. Similar to apophasis. e.g. The music, the service at the feast, The noble gifts for the great and small, The rich adornment of Theseus's palace . . . All these things I do not mention now." poisoning the well A logical fallacy (a type of ad hominem argument) in which a person attempts to place an opponent in a position from which he or she is unable to reply. Another technique by which the personality of a speaker is sometimes discredited is called poisoning the well. An enemy, when he poisons a well, ruins the water; no matter how good or how pure the water was, it is now tainted and hence unusable. When an opponent uses this technique, he casts such aspersions on a person that the person cannot possibly recover and defend himself without making matters much worse. post hoc A fallacy in which one event is said to be the cause of a later event simply because it occurred earlier e.g. The Cause of Malaria "Malaria was for centuries a baffling plague. It was observed that persons who went out at night often developed the malady. So, on the best post hoc reasoning, night air was assumed to be the cause of malaria, and elaborate precautions were taken to shut it out of sleeping quarters. Some scientists, however, were skeptical of this theory. A long series of experiments eventually proved that malaria was caused by the bite of the anopheles mosquito. Night air entered the picture only because mosquitoes preferred to attack in the dark." red herring 意思是为分散注意力而提出的不相干事实或论点 In logic and rhetoric, an observation that draws attention away from the central issue in an argument or discussion; an informal logical fallacy. Also called a decoy. reductio ad absurdum In argumentation and informal logic, a method of refuting an opponent's claim by extending the logic of the opponent's argument to a point of absurdity. See examples, below. Reductio ad absurdum may also refer to a type of argument in which something is proved to be true by showing that the opposite is untrue. Also known as indirect proof or proof by contradiction. Arguments by reductio (or 'indirect proof,' as they're sometimes called) establish their conclusions by showing that assuming the opposite leads to absurdity: to a contradictory or silly result. Nothing is left to do, the argument suggests, but to accept the conclusion. To prove: p. slippery slope 常见 In informal logic, slippery slope is a fallacy in which a course of action is objected to on the grounds that once taken it will lead to additional actions until some undesirable consequence results. Also known as the slippery slope argument and the domino fallacy. stacking the deck A fallacy in which any evidence that supports an opposing argument is simply rejected, omitted, or ignored. Stacking the deck is a technique that's commonly used in propaganda. "People sometimes make decisions by folding a piece of paper in half, and listing reasons in favor on one side, and reasons against on the other; then they decide intuitively which side has stronger (not necessarily more) reasons. This method forces us to look at both sides of an issue before we decide. In the incorrect form, we just look at half the picture; this is called 'stacking the deck.'" straw man 最恶心 Straw man is a fallacy in which an opponent's argument is overstated or misrepresented in order to be more easily attacked or refuted. tu quoque 最常见 A type of ad hominem argument in which a person turns a charge back on his or her accuser: a logical fallacy. Also called the "you too," the "two wrongs," or the "look who's talking" fallacy. undistributed middle The undistributed middle is a logical fallacy of deduction in which the middle term of a syllogism is not distributed in at least one of the premises. e.g. All men are mammals. Some mammals are rabbits, therefore some men are rabbits. (Even though the first two lines are correct, the middle term 'mammals' never once refers to all mammals. The middle term is thus undistributed and t