logical fallacies

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How to recognize these and rebut them. Logical Fallacies

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A close look at logical fallacies with examples

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Page 1: Logical fallacies

How to recognize these and rebut them.

Logical Fallacies

Page 2: Logical fallacies

Logical fallacies are arguments that are weak and really can not stand. They are easily identified and rebutted if you know what you are looking for.

Logical Fallacies are…

Page 3: Logical fallacies

Hasty generalization

Missing the point

Post hoc

Slippery slope

Weak analogy

Appeal to authority

Ad populum

Ad hominem and tu quoque

Appeal to pity

Appeal to ignorance

Straw man

Red herring

False dichotomy

Begging the question

Equivocation

The fallacies:

Page 4: Logical fallacies

You make a hasty generalization when you judge an entire group of people based on a stereotype that is based on only a small population.

Perhaps when you think of a librarian, you picture a straight-laced, boring old woman in glasses? This is a hasty generalization. Not all librarians are like that, but we stereotype them based on a few who are!

Hasty generalization

Page 5: Logical fallacies

Ask yourself about these things:

Are you relying on the opinions of only a few people?

Does the speaker or writer refer to “all” or “none”-extremes in their argument?

Are the examples in the argument only referring to a few examples, rather than an entire group or piece of evidence?

If your answer is Yes to any or all of these questions, you may be seeing a hasty generalzation.

Finding a hasty generalization

Page 6: Logical fallacies

The argument given supports a particular conclusion (X), but not the one the arguer hopes to address (Y). If some one wants to prove their point, but they don’t know how to, they use this argument then add their idea to the end of the argument.

Example:

The neighborhood is getting run down. It must be because of all the aliens who moved in over the

past year.

Missing the point

Page 7: Logical fallacies

• Does the evidence actually support the argument?

• Look at why the neighborhood actually is run down. Is it really because of aliens or maybe there are other reasons like the buildings are old, no one cleans things up? Etc.

• Does the alien theory really support the argument or is it meant to throw us off what the real problems are because the speaker hasn’t got a clue?

Find this fallacy

Page 8: Logical fallacies

This is a popular argument that when translated from Latin means after this or therefore, because of this…

• Also known as If….then arguments

• If this happens , then it is because of that. (It may not have anything to do with why something happens.)

• Example: Mary borrowed Scott’s I Pad II. The I Pad II no longer works, therefore, Mary broke it.

• Mary may not have had a thing to do with why the I Pad II no longer works, but it is an argument used by many people in many situations.

Post Hoc (aka false cause)

Page 9: Logical fallacies

Ask yourself this:

• If something happens, is it really caused by what the person argues? Are they really sick because they ate doodle bugs or is it just that they actually have the flu?

• Does the fact that something follows something else, prove that A caused B? If not, then this is a Post Hoc argument.

Finding the error…

Page 10: Logical fallacies

The person arguing states that some consequence will happen, but he has no way to support the claim. He asserts that if we take a step on a particular path, then we will slide down that “slippery slope”

Example: If we ban smoking, then people will start taking soft drugs and then move onto hard drugs, and the crime rate will go up and up. We should therefore prevent crime by allowing smoking (changingminds.org).

The argument does not make logical sense and needs to be used in emotional situations where not much logic is needed.

Slippery Slope

Page 11: Logical fallacies

Is this a realistic conclusion based on the arguments given or does it sound too far reaching to actually become a reality? Let’s break down the argument:

If we ban smoking…then will people REALLY start taking soft drugs, will they then begin committing crimes?

If the logic is faulty, then you can not make a rational connection between the problem and the solution.

If Rob likes Ashley, and Gerri likes Ashley,

then Rob will also like Gerri.

Not necessarily!

Ask yourself…

Page 12: Logical fallacies

We use analogies to compare unlike things to make a connection to an idea in literature, and in arguments alike. When the argument uses a false analogy, it does not necessarily compare things that connect in a way.

Example:

A. Dogs chase cats.

B. Cats chase mice.

C. Therefore, dogs chase mice.

See? Not necessarily the logical conclusion. A is related to B ; B is related to C, but A is not related to C.

False Analogy

Page 13: Logical fallacies

To argue with appeal to authority, drop the

name of a person supporting your claim

even if the person is not really an

authority on the subject.

Example: We should all support the green movement; People like Mr. Greene support it as well.

The reality is, Mr. Greene is not an expert in

Green energy. In fact, he is the local

pharmacist!

Appeal to Authority

Page 14: Logical fallacies

• Does the person referred to actually know about the subject you are arguing?

• Does the person have a specialized degree or certification in the area being argued?

• If the person cited has no expertise in the area, then this is a faulty appeal to authority.

• E = MC2

Ask yourself…

Page 15: Logical fallacies

This argument appeals to one’s desire to be popular, or one of the “in crowd”. It is similar to Bandwagon because the arguer is trying to get you to be one of the majority, when, in fact, there may not really be a majority.

Example: Everyone who bought the KIA love it.

Ad Populum

Page 16: Logical fallacies

• Can I make my own decisions without asking every one else what they think?

• Is this what I really think/believe?

• Do I decide based on what other people think, say or believe?

• If you can’t think for yourself and make an informed decision, then you are a prime target for Ad Populum

or Bandwagon fallacies.

Ask yourself…

Page 17: Logical fallacies

This literally means against the person. In our terms, it is just a way of slinging mud or character assassination.

Example: Charlotte is not the best person for the job because she is a mean, selfish person.

This argument does nothing to show whether Charlotte is experienced or knowledgeable about the position for which she is being considered. Instead, it attacks her personality.

Ad hominem

Page 18: Logical fallacies

• Focus on the reasoning of the argument, not the person’s character.

• If a person’s character is truly known to be horrible by the general public, then you should pay some attention to the argument, but do not base your conclusion solely on it.

• We all learned that Bill Clinton loves the ladies, but whether he is a good speaker has nothing to do with that. However, if you want him to speak at your local Faithful Spouses meeting, you may wish to choose another speaker!

Ask yourself…

Page 19: Logical fallacies

This appeal plays on our emotions and asks us to accept an argument based on pity for some one or something.

See the example opposite.

Appeal to Pity

Page 20: Logical fallacies
Page 21: Logical fallacies

• Are you in agreement with the argument because of personal feelings? Then think about what the arguer is asking you to believe.

• We all have causes that we believe in, but we do not have to act on every whim of emotion all the time.

• You do not have to buy Pillsbury crescent rolls to feel like you are at home.

Think…

Page 22: Logical fallacies