Rhetorical logical fallacies
1 / 26

Rhetorical / Logical Fallacies - PowerPoint PPT Presentation

  • Uploaded on
  • Presentation posted in: General

Rhetorical / Logical Fallacies. What is a Fallacy?. An argument must be based on sound reasoning Fallacies are flaws in reasoning that detract from the validity or soundness of an argument Sometimes their use is by accident; others, they are used to deliberately mislead or “win” an argument.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Presentation

Rhetorical / Logical Fallacies

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Rhetorical / Logical Fallacies

What is a Fallacy?

  • An argument must be based on sound reasoning

  • Fallacies are flaws in reasoning that detract from the validity or soundness of an argument

  • Sometimes their use is by accident; others, they are used to deliberately mislead or “win” an argument

Example: "Eating five candy bars and drinking two sodas before a test helps me get better grades. I did that and got an A on my last test in history.”

What’s wrong with this line of reasoning?

Answer: The argument is fallacious because it falsely assumes that since the one thing (eating five candy bars) immediately precedes the other (getting an A), the relationship is causal.

Categories of Rhetorical Fallacies

Since there are three primary argumentative modes, there are three categories of fallacies:

  • Logical (Logos) – Flaws in logical reasoning

  • Ethical / Authoritative (Ethos) – Appealing to authority or morality on its own terms

  • Emotional (Pathos) – Trying to manipulate emotionally or to scare people

Fallacies of Logic

  • Hasty Generalization

  • Post Hoc

  • Non sequitur

  • Equivocation

  • Begging the Question

  • Faulty Analogy

  • Stacked Evidence

Hasty Generalization

  • Conclusion is drawn based on little or insufficient evidence

  • Example: “That restaurant’s food is terrible! I ate there once and my food was undercooked.”

  • Why is this fallacious?

Post Hoc, Ergo Propter Hoc

  • Latin for “after this, therefore also this”

  • Assumes that because an event happens before another event, that the first event actually causes the second

  • Also known as false cause fallacy

  • Example: “A year after the release of the violent shoot-’em-up video game Annihilator, incidents of school violence tripled… surely not a coincidence.”

  • Why is this fallacious?

Non sequitur

  • Latin for “it doesn’t follow”

  • Argument does not follow any sort of logical sequence

  • Example: “It rained so hard that Jenn actually called me!”

  • Example: “My dog got so sick that my grandma made stew.”

  • What’s wrong with these arguments?


  • Commonly referred to as “half-truths”

  • A partially correct statement that tries to hide behind double meanings

  • Example: “I did not have sexual relations with that woman.” – Former President Bill Clinton

Begging the Question

  • Circular argument

  • The premise and the conclusion are the same thing stated differently

  • Example: “His lies are evident from the untruthful nature of his statements.”

Faulty Analogy

  • An inaccurate, inappropriate comparison between two things

  • Example: “Forcing students to attend cultural events is like leading cattle to slaughter.”

Stacked Evidence

  • Distorts an issue by overwhelmingly supporting or representing only one part of it

  • Usually done intentionally to make one particular part of an issue appear clearly favorable to the others

  • Example: “Cats are superior to dogs because they are cleaner, cuter, and smarter.”

Ethical / Authoritative Fallacies

  • False Authority

  • Authority as Evidence

  • Guilt by Association

  • Dogmatism

  • Ad Hominem

  • Strawman

False Authority

  • Claims that an assertion is true based solely on the person who made the assertion

  • Example: “Mr. King says that the sky is red, and Mr. King is smart, so it must be true.”

Authority as Evidence

  • A speaker uses his or her own authority to prove that a claim is true

  • Usually such claims are totally unrelated to the speaker’s own expertise

  • Example: “Dr. Pepper is smooth. Trust me – I’m a doctor.”

  • Example: “My friend would never rob a bank. Trust me.”

Guilt by Association

  • Assumes that an argument is true because the person involved is associated with someone or something negative

  • Example: “Tom’s friend robbed a bank, so Tom is a bad person.”


  • A claim is assumed true because the speaker believes it to be true

  • Otherwise known as “because I said so”

  • Example: “Penguins are reptiles, and that’s that.”

Ad Hominem

  • Instead of debating an issue, the speaker attacks the person who makes a competing claim

  • Often seen in political campaigns

  • Example: “How can we trust Ms. Ware to run the city when she can’t even handle her own marriage?”

  • Example: “Senator Kelly’s plan is terrible because Kelly is a communist.”


  • A speaker misrepresents or oversimplifies an opposing view in order to tear it down

  • Example:

    • A: We need to fix welfare.

    • B: Welfare is for terrorists. Do you really think we should be aiding terrorists?

Emotional Fallacies

  • Red Herring

  • Scare Tactics

  • Bandwagon

  • Slippery Slope

  • Either / Or

Red Herring

  • Using misleading or unrelated information to prove a conclusion

  • Example: "Winthrop should pave the lot behind Dinkins. Besides, I can never find a parking space on campus anyway."

Scare Tactics

  • Tries to manipulate people’s fears to sway their decisions

  • Example: “If you don’t vote for Q for President, the economy will implode and your family will starve.”


  • Implies that a choice is correct because it is popular

  • Often used in advertising – celebrity spokesperson

  • Example: “Five million Coke drinkers can’t be wrong!”

Slippery Slope

  • Argues that one thing automatically will lead to another – usually with disastrous results

  • The cause and effect relationship often is completely exaggerated or absurd

  • Example: “If we allow gay marriage, then people will start marrying their pets, and the fabric of society will crumble.”

Either / Or Choices

  • Setting up a false dichotomy for an issue

  • Inaccurately reduces an issue to two possible outcomes

  • Usually one outcome is absurd and the other is infinitely favorable

  • Example: “You can either approve the new tax plan or you can say goodbye to adequate emergency services!”

  • Login