Are There Any Fallacies in the Reasoning?

CSIT 58 Chapter 7

Fallacies

You’ve learned to identify issue and conclusion, reasons, ambiguities and assumptions. Now you’re ready to start evaluating the quality of the reasoning.

A fallacy is a reasoning “trick” that an author uses while trying to persuade you to accept a conclusion.

Common Fallacies

Many fallacies are so common they have been given formal names.

It’s not important to memorize the names, just to be able to identify that there is a fallacy.

Ad Hominem

Proving a point by attacking a person or group rather than ideas. Name-calling is a common practice.

From a letter to the L.A. Times 10-7-02 p. C8 regarding the a $28 billion award to a smoker:

All you need is 12 dimwitted jurors to fall for your victimization sob story, and you win the lawsuit lottery. The truth be damned. Just because 12 jurors say the moon is made of green cheese doesn’t make it true.

Emotional Language

Authors use showy terms that have an emotional appeal to sway you. They’ll often use glittering generalities to cover up a lack of specifics. For strong language, how about:

Sob story Lawsuit lottery Green cheese moon

Faulty Analogy

Analogy: an idea or policy that has been useful in some instances will be useful in another similar situation.

Faulty Analogy: there are significant differences between the two things being compared.

Scott Adams Dilbert strip 10/14/02 http://www.unitedmedia.com/comics/dilbert/index.html

Appeal to Questionable Authority or Tradition

We’ve always done it this way. Or X is against/for it so you should be too. Is X a reliable 

Our workers have always been happy working 9 5; there’s no need to change that schedule.



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Hasty Generalization

Inappropriately generalizing from a limited number of cases.

Gray Davis still can’t guarantee that the lights will stay on in California. So ladies and gentlemen, I ask you, if we can’t trust Gray Davis to keep the lights on, how can we trust him to run the sixth largest economy in the world?

From http://www.simonforgovernor.com

Ad Populum

Appeals to group-approved attitudes.

Most Americans agree that… Everybody knows that….

  

Americans want to be protected against terrorists. We must use face recognition systems in public gathering places.

That’s not fair. All the other kids get to go to the rave!

Everyone knows the governor is unreliable; if we keep trusting him not to raise taxes, we could all be in debt by next year.

Extension Fallacy

Attacking a position that appears similar to but is actually different from an opponent’s position. Then concluding that the opponent’s real position has been refuted.

I support the idea of one’s choice to have their belly button pierced. Everybody should have the freedom to express their uniqueness in a way that they really enjoy and makes them feel good about themselves. What is more of a unique way than self-expressing yourself through body decorations?

Adapted from Ravy Sam’s letter to the Press Telegram. 10-6-02 page A21

Also called straw man

The “straw man” here is the idea of freedom of expression to refute parental arguments against belly button piercing.

Parents are usually concerned with health issues like infections and tearing. They’re not against self-expression.

False Dilemma

The writer oversimplifies an issue by stating only two choices when there are really more. Watch for: either ….or… the only alternative is..

the two choices are… because A has not worked, only B will…

Example: False Dilemma

The Chinese government is so fierce about controlling the information dispensed among its citizenry that it recently shut down thousands of Internet cafes and blocked search engines Google and AltaVista.

Chinese citizens deserve to become full members of the Internet society. American companies must show support for our values and refuse to provide Internet services in China until these gag orders are lifted.

Companies must?

American companies must … refuse to provide Internet services in China

It’s presented as though there are two black and white options, no Internet service for the Chinese people or wide open freedom.

Red Herrings

The author diverts your attention away from the real issue. The “red herring” is the other issue he’s using to divert you.

Kids are experts

Why didn’t you call me when you didn’t come home by 11p.m. from your date?

My brother doesn’t have a curfew for dates.

“What Should Be” and “What Is”

This is often called wishful thinking.

Reality or “what is,” is often in conflict with “what should be.”

Computer game makers should not be forced to participate in a rating system. Parents should review the game content to see if they deem it appropriate for their child.

Confusing Naming with Explaining

Naming makes us think that we have identified something that the person has or is that makes him act accordingly. A different name for a behavior is presented as the cause of it.

Sony, Panasonic and other electronics manufacturers are against legislation requiring recycling fees. It’s big business versus the earth.

Big business is greedy and bad, earth is good

Perfect Solutions

If a solution doesn’t completely eliminate the problem, that doesn’t make it bad. It may be superior to no solution at all.

We should not go through the extra expense of installing a firewall because hackers will still find security holes.

Begging the Question

The speaker may put the burden on you to prove that his conclusion is not correct instead of giving reasons.

Isn’t is worth $10 a month to protect your home computer from hackers?

Show me that space aliens don’t exist!

Or he may build on an unproven assumption.

Have you stopped beating your wife?

More Begging the Question

Sometimes the “reason” is just the conclusion restated in a slightly different way. It’s circular reasoning.

Internet filtering software should be installed in schools because undesirable sites will be blocked.

Check Your Understanding:What Kind of Fallacy is it?

1.

2.

3.

4.

5.

6.

We need to buy a camera phone right away. Everyone else has one.

She doesn’t know anything about computer programming – she’s a blond.

Harbor should upgrade to Windows Server 2003; it works really well for Northrup.

I’ll never learn to use FrontPage—I tried working with it for 2 months and my web site is a mess.

You can stop eating animal products and be healthy or keep eating them and be unhealthy.

Mom, I am not looking at pornography, I’m studying for my computer class.

Answers

4.

5.

6.

1.

2.

3.

Ad populum Ad hominem or Hasty Generalization, it could depend on the context it was said in.

Faulty Analogy (There are significant differences between a company like Northrup and Harbor College). It is also a generalization.

Hasty Generalization False dilemma Red Herring.

End of Lecture