Author’s Reasoning: Valid and Fallacious

English I Beaulieu

Hall Dale High School

Monday, March 5, 14

Valid ReasoningClaims must be backed with reasoning. Reasoning should be based in logic.

Valid reasoning uses facts, statistics, or personal

experience to support their claim.

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Example

Becky tells her teacher that she is allergic to pollen, every time she is

outside for recess her allergies act up, and therefore the playground must have

a high pollen count.

This is valid because we see a logical sequence based on true statements.

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Fallacious ReasoningFallacy is an argument that does not

provide the necessary support to back up the given claims.

Fallacy is an error in reasoning.

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Most Common Types of Fallacious Reasoning

Slippery Slope

Hasty Generalization

Post hoc ergo propter hoc

Genetic Fallacy

Circular Argument

Either/Or

Ad hominem Ad populumRed Herring

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Slippery SlopeIf A happens, then B, C, ......, X, Y, Z, will happen too.

If we ban Hummers because they are bad for the environment,

eventually the government will ban all cars, so we should not ban

Hummers.

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Hasty GeneralizationA rushed conclusion before you have all the

relevant facts.

Even though it’s only the first day, I can tell this is going to

be a boring course.

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Post hoc ergo propter hoc

If A occurred after B, then B must have caused A.

I drank bottled water and now I am sick, so the water must have

made me sick.

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Genetic FallacyConclusion based on an argument that the

origins of a person, idea, institute, or theory determine its character, nature, or worth.

The Volkswagen Beetle is an evil car because it was originally designed by

Hitler’s army.

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Circular Argument

Restates the argument rather than actually proving it.

George Bush is a good communicator because he speaks

effectively.

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Either/Or Conclusion oversimplifies the argument by

reducing it to only 2 sides or choices.

We can either stop using cars or destroy the earth.

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Ad hominemAttack on the character of a person rather than

their opinions or arguments.

Green Peace’s strategies aren’t effective because they are all

dirty, lazy hippies.

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Ad populum

An emotional appeal that speaks to positive (patriotism/religion/democracy) or negative (terrorism/facism) concepts

rather than the real issue.

If you were a true American, you would support the rights of people to choose

whatever vehicle they want.

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Red Herring A diversionary tactic that avoids the key issues,

often by avoiding opposing arguments rather than addressing them.

The level of mercury in seafood may be unsafe, but what will fishermen do to support their

families.

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Sources http://knowyourmeme.com/memes/your-argument-is-

invalid

Author’s Reasoning Resource Handout

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