Fallacies: Irrelevant Premises

  • Certain types of defective arguments that occur frequently are known as fallacies. Fallacies are often psychologically persuasive but logically flawed.
  • We can divide fallacies into two broad categories: (1) those that have irrelevant premises and (2) those that have unacceptable premises.
  • Fallacies with irrelevant premises include the genetic fallacy (arguing that a claim is true or false solely because of its origin), composition (arguing that what is true of the parts must be true of the whole), division (arguing that what is true of the whole must be true of the parts or that what is true of a group is true of individuals in the group), appeal to the person (rejecting a claim by criticizing the person who makes it rather than the claim itself), equivocation (the use of a word in two different senses in an argument), appeal to popularity (arguing that a claim must be true merely because a substantial number of people believe it), appeal to tradition (arguing that a claim must be true or good just because it’s part of a tradition), appeal to ignorance (arguing that a lack of evidence proves something), appeal to emotion (the use of emotions as premises in an argument), red herring (the deliberate raising of an irrelevant issue during an argument), straw man (the distorting, weakening, or oversimplifying of someone’s position so it can be more easily attacked or refuted), and two wrongs make a right (arguing that your doing something morally wrong is justified because someone else has done the same thing).

Fallacies: Unacceptable Premises

  • Fallacies with unacceptable premises include begging the question (the attempt to establish the conclusion of an argument by using that conclusion as a premise), false dilemma (incorrectly asserting that only two alternatives exist), decision-point fallacy (arguing that because a line or distinction cannot be draw at any point in a process, there are no differences or gradations in that process), slippery slope (arguing, without good reasons, that taking a particular step will inevitably lead to a further, undesirable step or steps), hasty generalization (the drawing of a conclusion about a group based on an inadequate sample of the group), faulty analogy (an argument in which the things being compared are not sufficiently similar in relevant ways).

Persuaders: Rhetorical Moves

  • Critical thinking is also undermined by rhetoric, the use of nonargumentative, emotive words and phrases to persuade or influence an audience.
  • Rhetorical devices include innuendo (suggesting something denigrating about a person without explicitly stating it), euphemisms (words used to convey positive or neutral attitudes or emotions in place of more negative ones), dysphemisms (words used to convey negative attitudes or emotions in place of neutral or positive ones), stereotyping (drawing an unwarranted conclusion or generalization about an entire group of people), ridicule (the use of derision, sarcasm, laughter, or mockery to disparage a person or idea), and rhetorical definition (influencing opinion through an emotion-charged definition).
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