More common fallacies!

What you need to know…

Chapter 7

AD HOMINEM FALLACIES

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Argumentum ad hominem: themost common fallacy on earth.

Example:

“According to Al Gore, global warming isthe most serious threat facing us today.Folks, what a crock. Al Gore spends$20,000 each year on electricity in hisTennessee mansion!”

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The only crock here is thatargument! Why is it a fallacy?

Look at it logically:

Premise: All Gore spends $20,000each year on electricity.

Conclusion: Therefore global warmingis not the most serious threat facing ustoday.

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In case you still don’t see it:

Issue: Is global warming the mostserious threat?

Which of the following assertions isRELEVANT?

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GW will cause rising sea levels to swamp alleast coast cities by 2100.

GW will cause coral reefs to die within 30years.

CO2 levels have risen over 30% in the last 25years, due to GW.

According to a study published in Nature,current rates of warming will lead to extinctionfor 1 million species by 2050.

All Gore spends $20,000 a year onelectricity—NOT RELEVANT!

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ATTACK ad hominem

“What Al Gore says about air pollution isa joke! That clown will say anything toget attention!”

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CIRCUMSTANTIAL ad hominem

“What Al Gore says about air pollution ispure bull. Al Gore makes a fortune fromalternative energy investments. What doyou think he’d say?”

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INCONSISTENCY ad hominem

“Senator Clinton says we should get outof Iraq. What a bunch of garbagecoming from her! She voted for the war,don’t forget.”

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POISONING THE WELL

“Senator Clinton is going to give a talktonight on Iraq. Well, it’s just gonna bemore baloney. That gal will say anythingto get a vote.”

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GENETIC FALLACY

“Does God exist? Of course not. Thatidea originated with a bunch of ignorantpeople who knew nothing aboutscience.”

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GENETIC FALLACY:

Rejecting an idea as false because itcame from a defective source.

Rejecting some particular person’s ideaas false because there is somethingdefective about the person.

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Ad hominem:

GENETIC FALLACY:

“Does God exist? Of course not. Thatidea originated with a bunch of ignorantpeople who knew nothing about science.”

“John says God exists. What nonsense.He’s just saying that because he works fora church.”

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Circumstantial ad hominem:

New fallacy!

FALSE DILEMMA

Also known as Black/White; Either/Or;All/Nothing.

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FALSE DILEMMA

Example:

“Either we increase the number oftroops in Iraq or the terrorists will beattacking U.S. cities. Seems like asimple choice to me.”

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“PERFECTIONIST” version offalse dilemma

Example:

“It’s impossible to eliminate terrorismentirely. We should stop wastingmoney on it.”

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“LINE-DRAWING” version offalse dilemma

Example:

“ There shouldn’t be restrictions onviolence in the movies. After all, when isa movie ‘too violent’? You can’t draw aline.”

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Now two other famous fallacies:

STRAW MAN

SLIPPERY SLOPE

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STRAW MAN

Example:

“Twenty percent? You want to tip her20%???? Hey, maybe you want to giveher everything we make, but I franklythink that is ridiculous!”

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SLIPPERY SLOPE

Example:

“Twenty percent? You want to tip her20%? Hey, next thing you’ll want to tip25%! And then 30%! It will never end.”

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Two more famous twins:

BEGGING THE QUESTION

MISPLACING THE BURDEN OFPROOF

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MISPLACING THE BURDEN OFPROOF:

Example:

“Can I prove the Biblical flood reallyhappened? Hey, can you prove itdidn’t???”

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BEGGING THE QUESTION

Example:

“Can I prove the Biblical flood reallyhappened? Of course it happened! Whyelse would Noah build an ark???”

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What they all have in common:

They don’t demonstrate theirconclusion.

They don’t support their conclusion(they don’t make their conclusion morelikely).

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