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Three Basic Fallacies. All the fallacies we deal with are forms of three basic fallacies:. - Irrelevant Reason . - Hasty Conclusion. - Problematic Premise . Irrelevant Reason (relevant?). Also called “Non-Sequitur” (“It does not follow”). The arguer puts forth a
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Three Basic Fallacies • All the fallacies we • deal with are forms of • three basic fallacies: - Irrelevant Reason - Hasty Conclusion - Problematic Premise
Irrelevant Reason (relevant?) • Also called “Non-Sequitur” • (“It does not follow”) • The arguer puts forth a • premise which, though it • may be true, has nothing to • do with the conclusion.
Irrelevant Reason E.g.: A former Health Minister, when asked in the Commons about the food value of Corn Flakes, responded: “The milk you have with your Corn Flakes has great nutritional value.”
Hasty Conclusion (sufficient?) • Even when the premises are • relevant, they may not give • enough evidence to support • the conclusion. • Beware of anecdotal • evidence -- relying on only • one or two “incidents.”
Hasty Conclusion E.g.: “University profs really have it pretty easy. We have a cottage next door to a prof, & he’s there from late April right through September, fishing and relaxing.”
Problematic Premise (acceptable?) • Each premise of an argument • should be defended, unless it • is already clearly true because • it is common knowledge, or • offered by an expert witness, • or is only being offered for • the sake of argument, etc.
Problematic Premise E.g.: “Many young people who today hold responsible jobs were once the recipient of the lash, & if there are any bleeding hearts who think this is callous and inhuman, let them read Proverbs …”
To Sum Up: • Irrelevant reason is a strong • charge: an argument guilty of • it must be abandoned, and • the arguer must start over.
To Sum Up: • Hasty Conclusion is a weaker • charge; it just means more • evidence needs to be given • before the conclusion can be • accepted -- not that the basic • argument and conclusion are • necessarily wrong.
To Sum Up: • Problematic Premise is the • weakest charge of all: it just • means the arguer needs to • supply more evidence for one of • his or her premises.
To SumUp: • an argument is not a fight; • it is an attempt to show • evidence in support of a • position or belief • an informal fallacy is an • argument with problems • in its premises
To Sum Up: Remember: It is not enough to label an argument a fallacy -- you must be able to explain why the argument is fallacious.
Source: Adapted from Johnson, R.H. and Blair, J.A. Logical Self-Defense (First Edition). Toronto, McGraw-Hill Ryerson, 1977