Following are the main learning objectives from the chapter.
You should understand that a logical fallacy is an argument that contains a mistake of reasoning. Further, you should note that . . .
fallacies are divided into two broad categories:
Fallacies of relevance, and
Fallacies of insufficient evidence
The Concept of Relevance
Students should grasp the concept of relevance. In this aim, students should . . .
understand that one statement is relevant to another when it provides at least some evidence or reason for thinking that the second statement is true or false.
understand that a statement is positively relevant to another statement if it counts in favor of that statement.
a statement can be positively relevant to another statement even if it false.
whether a statement is relevant to another often depends on the context in which the statements are made.
understand that a statement is negatively relevant to another statement when it counts against that statement.
understand that a statement is logically irrelevant to another statement if it counts neither for no against that statement.
Fallacies of Relevance
You should understand that a fallacy of relevance occurs when an arguer offers reasons that are logically irrelevant to his or her conclusion. You should also understand and be able to identify the following fallacies of relevance:
Personal Attack (Ad Hominem): This fallacy occurs when a claim or argumentis rejected by attacking the person rather than the person's claim or argument. Most personal attacks follow the pattern:
X is a bad person.
Therefore X's argument must be bad.
Attacking the Motive: This fallacy occurs when an arguer criticizes a person's motivation for offering a particular argument or claim, rather than examining the worth of the argument or claim itself. Attacking the Motive follows the pattern:
X is biased or has questionable motives.
X's argument or claim should be rejected.
Look Who's Talking (Tu Quoque): When an arguer rejects another person's argument or claim because that person fails to practice what he or she preaches. Tu Quoque follows the pattern:
X fails to follow his or her own advice.
Therefore, X's claim or argument should be rejected.
Two Wrongs Make a Right: This fallacy occurs when an arguer attempts to justify a wrongful act by claiming that some other act is just as bad or worse. Two Wrongs Make a Right generally follows the pattern:
Others are committing worse or equally bad acts.
Therefore my wrongful act is justified.
Scare Tactics: This fallacy occurs when an arguer threatens harm to the reader or listener and this threat is irrelevant to the truth of the arguer's conclusion.
Appeal to Pity: This fallacy occurs when an arguer attempts to evoke feelings of pity or compassion, when such feelings are not logically relevant to the arguer's conclusion.
Bandwagon Argument: This fallacy occurs when an argument plays on a person's desire to be popular, accepted, or valued, rather than appealing to logically relevant reasons or evidence. Bandwagon Arguments generally follow the pattern:
Most (or a select group of) people believe or do X.
Therefore, you should believe or do X.
Straw Man:This fallacy occurs when an arguer distorts an opponent's argument or claim in order to make it easier to attack. Straw Man arguments follow the pattern:
X's view is false or unjustified [but where X's view has been unfairly characterized].
Therefore, X's view should be rejected.
Red Herring: This fallacy occurs when an arguer tries to sidetrack his or her audience by raising an irrelevant issue and then claims that the original issue has effectively been settled by the irrelevant diversion.
Equivocation: This fallacy occurs when a key word is used in two or more senses in the same argument and the apparent success of the argument depends on the shift in meaning.
Begging the Question: This fallacy occurs when an arguer states or assumes as a premise the very thing he or she is trying to prove as a conclusion.