Presentation on theme: "Three Basic Fallacies All the fallacies we deal with are forms of three basic fallacies: - Irrelevant Reason - Hasty Conclusion - Problematic Premise."— Presentation transcript:
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 Sum Up: 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