Here's a garden stroll through fallacy.
Teaching fallacies has some problems. Human logic is something that humans have not succeeded utterly in describing, and categories for fallacies vary somewhat from person to person and text to text. However, since students will collect fallacies for an assignment, let's go through some examples. Just please take the facile categories with a grain of salt, and remember too that this list is not exhaustive. Also, the presence of a fallacy in an argument does not mean that the point the argument intends to support has no validity; it just means that a hole exists in the supporting argument.
Fallacy finds with comments would make great blog entries, by the way.
Inductive fallacy -- Induction involves generalization from experience or experiment. One observes a sample population, then judges that certain things will be true in general that seem to have been true in the sample population. Obviously, problems occur insofar as the population experienced differs from the population to be judged:
False Analogy - two actions or things taken as similar do not resemble each other in some significant aspect: "Students have to work, and mules have to work: If you want either to do well, you need to put a carrot in front of them and a stick behind them."
Hasty Generalization - a conclusion is drawn about a wide range of things using a small range of examples. "Joe the quarterback failed his English class. Football players are sure lousy students!"
Unrepresentative sample- The thinker generalizes from a sample that in some ways does not represent the majority of instances of the class of things under discussion.
Exclusion - The thinker ignores relevant information. "Jim has been here all semester, so he'll be here tomorrow" (even though he's running a fever of 103 degrees and his car burst into flrmes while he was driving to his mother's to complain because she turned him in to the IRS.
Slothful induction - The thinker ignores a significant pattern in the data."I get too busy at the end of each semester, but it's not bad planning: It's just that things happen that I don't expect."
Fallacies of Deduction -- These may take valid premises, but misapply them so that conclusions might not be correct. In these, the errors or abuses involve misuse of operators or shifts in the meaning of terms.
Fallacies of Distraction These deductive fallacies misuse an operator to relate premises to premises or premises to conclusions in ways that are not valid.
False dilemma - The thinker presumes fewer options exist than might. "Either you're with us, or you're with the terrorists," or "If you're not part of the solution, you're part of the problem."
Complex Question - Two distinct statements are treated as though they were coterminous or inseparable. "So you think it's OK to reduce welfare and let that small child starve?" "Won't you support our troops and authorize the new defense budget?" One must establish that one factor genuinely is consequent upon the other.
Slippery Slope - One idea is related to one or a series of similar (or not so similar!) ideas, which are usually less acceptable. "If we allow same-sex marriages, pretty soon we'll have to honor marriages to multiple partners, then to sheep or pigs." Here, unless the speaker can invent some reason to equate same-sex marriage with polygamy and bestiality, the argument lacks validity.
Argument from Ignorance - Because a proposition cannot be or has not been disproven, the thinker claims it's proven true. "You can't prove God does not exist, so obviously She does." Note that this argument works equally well -- or equally poorly -- in reverse: "You can't prove God does exist, so obviously She does not."
Changing the Subject - Some invalid use of operators involves applying the argument to something that's not relevant, or applying something that's not relevant to the argument.
Ad hominem - Even a valid attack against a person's character has no necessary relation to the correctness of that person's idea. "You say pot hurts my studies, but you do seem to like your whiskey sours." Notice that if one person makes an argument based on authority ("It's true because Joe says so!"), the personal attributes of the authority may have some provisional relevance ("Well, Joe's specialty is in another field!")
Style over Substance - Graceful or graceless argument does not itself render an idea true or false. "How can you believe Bush? The guy can't say three words without putting his foot in his mouth." "But that's just why I trust him: He's so down-to-earth and anti-intellectual." (Check out newspaper coverage of possible presidential candidates for '08 for a river of style over substance arguments.)
Appeal to Authority - People pretend authority; real authorities disagree. Even Aristotle claimed that flies have four legs. (BTW, just because this is listed as a fallacy does not mean you'll get away with no references in research papers!)
Appeal to Motives - Just because one might want something to be true or false bears no relation to whether or not it is.
o Prejudicial language - People sometimes hold a thing true of false because it's couched in complementary or nsulting terms. "Hey, it's just common sense."
o Pity - I'd feel so bad were this not correct that you must believe that it's so. "I'm working so hard on this CD for this class that you'd better like it."
o Force - If you disagree, woe unto you.
o Popularity - a position is held to be true because it's popular or supported by someone popular or held to be popular or because one may become popular. Ads with some young lady draped over the hood of a car or a basketball player selling sneakers are cases in point.
Cause and Effect Fallacies These tend to just miss the point -
Coincidental correlation - One thing happened after another, so the first must have caused the second: "Leonard can command the Sun. He said, 'I command that the sun shall rise tomorrow,' and lo, it did."
Joint Effect - Two effects of one cause are treated as cause and effect: "The violence in Afghanistan was caused by the war there."
Reverse cause-effect - Cause is treated as effect, and vice-versa. "I'm a lousy writer anyway, so I don't bother to proofread my papers."
Complex Cause - Significant causes are ignored, as though only one cause were crucial.
Insignificant cause - One cause heralded as vital is not: "The maraschino cherries on these sundaes are probably fattening; maybe I'll have them leave the cherry off my second."
Friday, April 20, 2007
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5 comments:
If we find other kinds of fallacies can we use them in our 10? (For example there is the red herring and the gambler's fallacy that I found in another website)
Yes, although not everything that's called a fallacy is one, exactly. Be sure that your example involves a malformed thought: that is, the structure of the way the thought is expressed does not support the ultimate conclusion or claim that someone is trying to put forth.
But yes, a red herring would work, as would the gambler's fallacy, which is kind of interesting -- it's also called the drunkard's walk, incidentally.
Just for clarification- when posting to the blog we should include the image, list the type of fallacy (induction, deduction, false analogy etc) and explain why it's a fallacy? How long (typically) should this explanation/ summary be?
nizkor.org
Go to fallacies and scroll down to Captain's Log to get a long explanation of the fallacy assignment.
(Then fire away with any other questions)
The type of fallacy may be useful, but is not always necessary.
Do explain how the fallacy works.
Usually the explanation can be done in 3 or 4 sentences. Sometimes less. Sometimes it takes longer, usually because the point of the text is implicit, not explicit, so it takes a bit longer to explain what the statement is so that one can criticize it.
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