1 discourse fallacies psc 202 fall 2004 prof. northrup
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Discourse FallaciesPSC 202Fall 2004Prof. Northrup
Formal and Informal FallaciesFallacyFormal fallacyInformal fallacy
Informal Fallacies Four TypesFallacies of Ambiguity
Fallacies of Relevance
Fallacies of Presumption
Fallacies of Weak Induction
I. Fallacies of Ambiguity (5)Based on ambiguous use of terms or phrases
That is, the term or phrase can have more than one meaning
I. 1) EquivocationA shift in meaning of a word in one premise to the next, or from a premise to the conclusionE.g.All cats are small domestic animalsAll lions are catsSo, all lions are small domestic animalsCan be done conversationally
I. 2) AmphibolyLike equivocation, but applies to a phraseThe meaning of the phrase shiftsExample: Methodists and doubtLeader: Rise and greet the morning.People: Cast off your sleep and doubt.
I. 3) AccentOccurs when a passage is incompletely quoted or a passage is taken out of context or bothExamples:Sound bitesTaking only words that support your side
I. 4) DivisionWhen a claim that is true of an entire class of things is mistakenly applied to a single member of the class, ORA claim that is true of a whole thing is mistakenly applied to a part of a wholeExample: state vs. national trends
I. 5) CompositionThe mirror image of divisionInferring that a whole or an entire class of objects has certain properties because one of the parts of the whole, or one member of the class, has that propertyExamples:Because of hurricane Ivan, there was flooding in Louisiana today.The hood of my car is red, so my car is red.
II. Fallacies of Relevance (8)Assume a false premise or reach a conclusion that is not supported by the premisesOften used by politicians
II. 1) Appeal to ForceArgumentum ad baculumAn argument includes an implicit but unwarranted or inappropriate threatConsider:You should make a contribution to the Democratic candidate. After all, you are currently an employee of this company.
Appeal to Force - CaveatNot a fallacy if the threat is legitimateConsider:Watch your speed. Police use radar.
II. 2) Personal AttackArgumentum ad hominemOccurs when replying to an argumentThe person, not the argument, is attackedCalling credibility into question
Personal Attack continued 1Tricky sometimes valid to question E.g. expert witness in a trialExample? Campaign strategy of accusing opponent of flip-flopping
Personal Attack continued 2Tu quoque (literally, you too)You do it, why shouldnt I?Sarcasm as a responseI see you've set aside this special time to humiliate yourself in public.
II. 3) Mob AppealArgumentum ad populumAssumption that some type of popular appeal is a sufficient reason to engage in an action or hold a beliefTypical formsInclusion: Doing x (e.g. voting for this candidate) makes you feel good, so you should do it. Exclusion: Not doing x excludes you from the norm (of the mob)Appeals to emotion (e.g. Hitlers speeches)Family values?
II. 4) Appeal to PityArgumentum ad misericordiumAssumes that suffering is a sufficient reason to engage in an action or hold a belief (e.g. charity call)Possibly valid moral reason but irrational solutionOr may not be a cause for pity So must ask two questions:Is there moral force to the claim of sufferingIs the solution a good one
II. 5) StereotypingGeneral claim about a group that is falsebecause not true of that group There was a blonde, a red-head and a brunette not more true of that group than any otherRed-heads have bad tempersclaim has some validity but not of the groups makingNorthern Ireland Protestant claim that Catholics are lazy because they dont get jobsAlso called the genetic fallacy
II. 6) Straw ManWhen an argument is misrepresented and the misrepresentation is criticizedCan be done by claiming that there is an underlying premise that you have now revealed, and its wrongCan be done by misrepresenting the conclusion, and then criticizing the conclusion
II. 7) Red HerringA response to an argument that confuses the issues, thus causing a distraction from the actual argumentSmith factory exampleDistraction may be a valid concern, but doesnt address the argument at hand
II. 8) Irrelevant Conclusionnon sequitur (doesnt follow)When a conclusion is drawn from an argument not suggested by the premisesObvious example - an invalid deductive argument:All aardvarks are mammalsAll mammals are vertebratesSo, some aardvarks are good petsHunting example
III. Fallacies of Presumption (4)Assumes something that isnt stated and does so incorrectlyassumes the conclusion as a premiseassumes that the premises contain all the relevant information while they do notUnlike a deductive argument where the premises entail the conclusion, that is, the premises logically result in the conclusion
III. 1) Begging the QuestionConclusion is assumed as one of the premisesGeorge Bush is the President because George Bush is PresidentDifferent words, same meaningGeorge Bush is the President of the US, since George Bush holds the highest office in the USTrue, but proves nothingCircular argument: made up of several arguments where the conclusion of the last is a premise of the first
III. 2) Complex QuestionAssumes a previous question has been answeredHow long have you been cheating on tests?Question by itself doesnt constitute a fallacy; has to be part of an argumentAn implicit argument can often by found in a question (immigration example)Caveat: Not a complex question if embedded in a longer argument where the premises are explicitly stated
III. 3) Suppressed EvidenceWhen you know there is evidence contrary to your position, yet you suppress the evidenceE.g. tobacco companies
III. 4) False DichotomyOccurs in the case of a disjunctive syllogism (either/or argument)Maria is either a Democrat or RepublicanMaria is not a DemocratSo she is a RepublicanIf disjunctive premise is false, the conclusion is falseExample: 1950s motto, Better dead than red
IV. Fallacies of Weak InductionRemember = inductive arguments are probable argumentsFallacy occurs when insufficient evidence is providedWeak induction fallacies occur when evidence cited is weak or incompleteevidence contrary to the conclusion is ignored
IV. 1) Appeal to AuthorityIncorrect use of authorityAssuming authority in one field implies authority in anotherAppeal to something as an authority (e.g. custom, popular opinion) when it is not
IV. 2) Appeal to IgnoranceA claim is made, eitherthat since there isnt any evidence that a proposition is false, it must be true, orthat since there isnt any evidence that the proposition is true, it must be falseNuclear power plant exampleCaveat: Some statements can look like an appeal to ignorance but arent
IV. 3) Hasty GeneralizationWhen a conclusion is reached on the basis of insufficient evidenceCan happen when a conclusion is drawn from an atypical sample or too small a sample
IV. 4) False CauseSomething is taken to be a cause when it isnt (non causa pro causa, not a cause as a cause)Advertising tacticOne event follows another; first event is identified as the cause (post hoc ergo propter hoc, before therefore because)e.g. superstitionsSingle cause identified but a complex situation Ronald Reagan ended the Cold War
IV. 5) Slippery SlopeChain of causal claims with one or more of them falseOften characterized by consequences getting progressively worseCigarettes lead to heroinCaveat: There are valid causal chainsPolitical issues like gun control - slippery slope or not?
IV. 6) Weak AnalogyAn argument that uses analogy to persuade, but wherethere are ways in which the points of comparison are insufficient to support the claim or there are significant non-analogous points among the things compared