Logical Fallacies (1)

Logical Fallacies

Logical Fallacies

Objectives

  • Define the different logical fallacies.
  • Distinguish the logical fallacies from one another.
  • Create examples of each logical fallacy.

Logical Fallacies

A fallacy in reasoning weakens an argument and makes it false or unreliable.

Logical Fallacies:

  • are flawed, deceptive, or false arguments that can be proven wrong with reasoning.
  • are any kind of error in reasoning that renders an argument invalid.

Reasoning

1. Deductive Reasoning

Requires one to start with few general ideas called premises and apply them to a specific situation.

Its most basic form is the syllogism, where two premises that share some idea support a conclusion.

If A = B and C = A, then B = C.

  • All cars have wheels. My vehicle is a car. Therefore, my vehicle has wheels.
  • All birds have feathers. A penguin is a bird. Therefore, a penguin has feathers.
  • All mammals have lungs. A whale is a mammal. Therefore, a whale has lungs.

2. Inductive Reasoning

Uses specific observations to reach a general or wider conclusion.

A few particular premises create a pattern which gives way to a broad idea that is likely or unlikely true.

  • Mango is a fruit. The box is full of fruits. The box is full of mangoes.
  • Every swan I have seen is white. I have seen many swans in different places. Therefore, all swans are probably white.
  • Every time I eat peanuts, my throat swells up. I ate peanuts last week, and my throat swelled up. Therefore, I may have a peanut allergy.

Types of Logical Fallacies

1. Hasty Generalization

Makes a sweeping statement without considering all of the facts.

It is a conclusion based on insufficient or biased evidence.

2. Bandwagon Fallacy / Ad Populum

Presents the thoughts of a group of people in order to persuade someone to think the same way.

3. Red Herring

An argument that uses confusion or distraction to shift attention away from a topic and toward a false conclusion.

4. Ad Hominem

An attack on a person’s character or personal attributes in order to discredit their argument.

5. Straw Man

Distorts an opponent’s claim so that it is easier to refute, or when someone tries to refute a point someone made by giving a rebuttal to a point they did not make.

6. False Dichotomy

Presents two options and acts as if there are no other choices. Also known as the "either/or" fallacy.

7. Appeal to Hypocrisy

Deflects criticism away from oneself by accusing the other person of the same problem or something comparable.

8. Appeal to Pity

Ad misericordiam is a logical fallacy where someone tries to win support for their argument by eliciting pity or sympathy, rather than providing a valid or relevant reason for their position.

Examples

Hasty Generalization

  • People nowadays only vote with their emotions instead of their brains.
  • Her ex-boyfriend cheated on her. Boys are cheaters.
  • Anyone who supports a thief is a thief.

Bandwagon Fallacy

  • McDonald’s has served over 99 billion, so you should let them serve you too.
  • If you were a millennial, you should have a TikTok account because everyone’s using it.

Red Herring

  • The level of mercury in seafood may be unsafe, but what will fishers do to support their families?

Ad Hominem

  • A mother rejects the judgment of a male pediatrician because he has never been a mother and could not possibly understand the child’s situation.

Straw Man

  • Person A: "We should have more comprehensive healthcare to make sure everyone gets the treatment they need."
    Person B: "Person A wants to turn our entire health system into a socialist system where the government controls everything. That's clearly a bad idea."

False Dichotomy

  • Eat an apple a day or you will get sick.

Appeal to Pity

  • "My client might have robbed the bank, but his family would be devastated if he went to jail."

Thank You

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