Relevance fallacies! What you need to know… Chapter 6.

Relevance fallacies!

What you need to know…

Chapter 6

What is a fallacy?

An argument that doesn’t really support or prove what it is supposed to support or prove.

Still, it may seem convincing.

© 2015 McGraw-Hill Higher Education. All rights reserved. 2

What’s a relevance fallacy?

A ‘red herring,’ a distraction. An argument that is not really relevant

to its conclusion.

“You tell me it’s dangerous to text when I’m driving, but I have seen you doing it.”


© 2015 McGraw-Hill Higher Education. All rights reserved.

AD HOMINEM FALLACIES

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If a speaker or writer attempts to dismiss someone’s position by discussing the person rather than attacking his or her position, a fallacy is committed:

Argumentum ad hominem.



Argumentum ad hominem is the most common fallacy on earth. Example:

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

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The only crock here is that argument! Why is it a fallacy? Look at it logically: Premise: All Gore spends $20,000

each year on electricity. Conclusion: Therefore global warming

is not the most serious threat facing us today.

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In case you still don’t see it:

Issue: Is global warming the most serious threat?

Which of the following assertions is RELEVANT?

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

GW will cause coral reefs to die within 30 years.

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

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

Al Gore spends $20,000 a year on electricity—NOT RELEVANT!

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Let’s look at some varieties of Argumentum ad hominem



Abusive ad hominem

“What Al Gore says about air pollution is a joke! That clown will say anything to get attention!”

The speaker is simply bad-mouthing Mr. Gore.

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Circumstantial ad hominem

“What Al Gore says about air pollution is pure bull. Al Gore makes a fortune from alternative energy investments. What do you think he’d say?”

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Inconsistency ad hominem

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

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Three more kinds of ad hominem

Poisoning the well Guilt by association Genetic fallacy



POISONING THE WELL

Trying to dismiss what someone is going to say, by talking about his/her character or circumstances or consistency.

“Senator Clinton is going to give a talk tonight on Iraq. Well, it’s just gonna be more baloney. That gal will say anything to get a vote.”

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Guilt by association

“You think waterboarding is torture? That sounds like something these left-wing college professors would say.”

Listeners are supposed to think calling waterboarding torture is “guilty” by virtue of its alleged association with supposedly left-wing college professors.



GENETIC FALLACY:

Rejecting an idea because it came from a presumed defective source.

A fallacy that occurs when someone argues that the origin of a contention in and of itself automatically renders it false.

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GENETIC FALLACY

“Does God exist? Of course not. That idea originated with a bunch of ignorant people who knew nothing about science.”

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GENETIC FALLACY:

“Does God exist? Of course not. That idea originated with a bunch of ignorant people who knew nothing about science.”

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

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Circumstantial ad hominem:

Compare:


Another famous fallacy:

THE STRAW MAN

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STRAW MAN

We are witnessing a Straw Man fallacy when a speaker or writer attempts to dismiss a contention by distorting or misrepresenting it.

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STRAW MAN

Example: “Twenty percent? You want to tip her

20%???? Hey, maybe you want to give her everything we make, but I frankly think that is ridiculous!”

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New fallacy!

FALSE DILEMMA Also known as Black/White; Either/Or;

All/Nothing; Ignoring Other Alternatives

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“Either we allow the oil companies to drill for oil in the Gulf or we will be at the mercy of OPEC. Therefore we shouldn’t prevent the oil companies from drilling for oil in the Gulf.”

The False Dilemma fallacy happens when someone tries to establish a conclusion by offering it as the only alternative to something we will find unacceptable, unattainable, or implausible.



FALSE DILEMMA

Example: “Either we increase the number of

troops in Iraq or the terrorists will be attacking U.S. cities. Seems like a simple choice to me.”

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“PERFECTIONIST” version of false dilemma Example: “It’s impossible to eliminate terrorism

entirely. We should stop wasting money on it.”

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“LINE-DRAWING” version of false dilemma Example: “ There shouldn’t be restrictions on

violence in the movies. After all, when is a movie ‘too violent’? You can’t draw a line.”

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Two more famous twins:

MISPLACING THE BURDEN OF PROOF

BEGGING THE QUESTION

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MISPLACING THE BURDEN OF PROOF

This fallacy occurs when an attempt is made to support or prove a point by trying to make us disprove it.

“Obviously, the president’s birth certificate is a forgery. Can you prove it isn’t?”



MISPLACING THE BURDEN OF PROOF: Example: “Can I prove the Biblical flood really

happened? Hey, can you prove it didn’t???”

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Appeal to Ignorance

This is a variation of the fallacy of Misplacing the Burden of Proof.

It occurs when it is argued that we should believe a claim because nobody has proved it false.



This fallacy occurs when a speaker or writer tries to “support” or “demonstrate” a contention by offering as “evidence” or “proof” what amounts to a repackaging of the very contention in question.


“Obviously the president told the truth about Benghazi. He wouldn’t lie to us about it.”



Another example: “Can I prove the Biblical flood really

happened? Of course it happened! Why else would Noah build an ark???”

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What all these fallacies have in common: They don’t demonstrate their

conclusion. They don’t support their conclusion

(they don’t make their conclusion more likely).

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APPEAL TO EMOTION&

IRRELEVANT CONCLUSIONS

Next:


Relevance fallacies! What you need to know… Chapter 6.

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