Friday, September 4, 2009

FALLACY: Appeal to authority

APPEAL TO AUTHORITY is sort of the reverse of ad hominem. Instead of disbelieving something because of the source, it's believing something because of the source. The "authority" might be a doctor, world leader, or other famous person. In other words, someone who would probably know more than you do.

Since we can't know everything, we often rely on the judgments of authorities and experts. It's not a fallacy to assume that an expert is correct when they are discussing their area of expertise. For example, if your doctor tells you that your arm is broken, and shows you the X-ray, you can be pretty sure she knows what she's talking about.

But it is a fallacy to assume a source is infallible, or always right. Even doctors aren't perfect, which is why patients seek what is called a “second opinion."

The ad shown here is the kind of cigarette ad that used to appear in newspapers and magazines. How does it appeal to authority? Would doctors approve of cigarette smoking today?

Here are other examples of APPEAL TO AUTHORITY.

Thomas Jefferson said it, so it must be true.

It's in the bible, so it must be true.

Ayn Rand said it, so it must be true.

It also happens in advertising:

Johnny Depp is awesome.
He was eating Sugar Bomb Cereal in that commercial.
He said that Sugar Bomb Cereal was the best, healthiest cereal on the market.
Therefore, I am going to eat Sugar Bomb Cereal every day.

Johnny Depp might be an expert on acting. But is he a doctor or dietitian? He might be qualified to talk about making movies, but is he qualified to discuss the health benefits of breakfast cereal?

FALLACY: Ad hominem

Argumentum ad hominem is a Latin phrase that means “argument against the man.” The AD HOMINEM FALLACY is when the argument challenges the person rather than the truth of the topic.

It goes like this:


Captain Jack Sparrow says Elizabeth Swann is in trouble.
But Captain Jack Sparrow is a pirate, rogue, and a liar.
Therefore, Elizabeth Swann must be safe.

The topic is Elizabeth being in trouble. The person saying she is in trouble is Jack. It is certainly wise to distrust someone who has lied to you before. But, logical arguments are about finding the truth, and we cannot discover the truth by assuming someone is lying. Not even pirates lie all the time.

Another way to attack the individual, rather than the topic, is to say that the person is not an expert.

Butterfly Greentree says that global warming is destroying our environment.
She's just a crazy tree-hugging hippy, not a scientist.
Therefore, we don't have to worry about global warming.


Are we certain Ms. Greentree is crazy? Do we know she is a hippy? And if she is a hippy, does that have any bearing on the truth of her claims?
Are hippies always wrong? Are crazy people always wrong? The old saying goes, "Even a broken clock is right twice a day."

When the idea of Global Warming was first discussed, many people did not believe it. But we now know that the Earth's average global temperature has increased over the past century, and is expect to continue rising over the next 100 years. That knowledge is based on scientific evidence, not whether or not someone hugs trees.

Another variation of Ad Hominem is AD HOMINEM TU QUOQUE (too KWOH-kwee) or the You Too Fallacy. It goes like this:

Thomas Jefferson wrote that “All men are created equal.”
But Jefferson owned slaves all his life.
Therefore, everything he wrote and claimed to believe was a lie.


The fact that a person's claims are not consistent with his or her actions might indicate that the person is a hypocrite (a person who acts against what they claim to believe). But this does not prove his or her claims are false. In the above case, whether Jefferson owned slaves or not has no bearing on whether freedom and equality are desirable ideals, and whether or not Thomas Jefferson aspired to them.

IDENTIFY ad hominem on TV, in the news, or in movies.

FALLACY: Appeal to fear

This is similar to the fallacy of Appeal to Emotion. An APPEAL TO FEAR is when a person tries to support his or her argument by scaring you, or by creating doubt and prejudice.

A Red Ryder BB gun is very dangerous.
You'll shoot your eye out.
Therefore, you should ask for another gift.

Mothers make these kinds of arguments all the time. “Don't climb on that, you'll fall and break your arm.” “Don't talk while you chew your food, you'll choke to death.” “Don't talk to strangers, you'll get kidnapped.”

These statements sometimes, unfortunately, turn out to be true. Children do fall and break their arms, people do choke on their food, and strangers are sometimes dangerous. It is important to listen to your mother (and father, grandparents, teacher, etc.)!

But, when we're talking about logical arguments, and determining truth, the APPEAL TO FEAR is a fallacy. Examine this argument:

If you don't believe in god, you will go to hell when you die.
Hell is full of suffering for all eternity.
Therefore, you should believe in god.

This sort of argument gives you scary premises, but do those premises actually support the conclusion? Whether you believe in god or not, this argument is a fallacy because scaring people does not prove or disprove the existence of a higher power.

Religions, governments, politicians, and big companies all use APPEAL TO FEAR:

“Don't vote for Barack Hussein Obama, he is friends with terrorists.”

“Allowing gay people to marry will destroy American families.”

“If we don't give taxpayer money to the banks, our whole economy will collapse.”

“Chew this gum or else you will have bad breath and no one will ever kiss you.”

Pay attention when you watch TV commercials, listen to politicians, or read newspapers and magazines, and keep a list of the APPEALS TO FEAR.

FALLACY: Appeal to emotion


Earlier we saw how products are advertised to appeal to your emotions rather than your intelligence. This happens not only in commercial advertising, but also in politics.

Lets examine this political ad. It was created in order to convince people to vote for John Tyson Jr. in Mobile, Alabama. Let's put it in the form of a logical argument:

Don't sit by... SILENT.
You can SAVE lives.
Therefore, vote for John Tyson Jr.


Do the premises support the conclusion? Are we, the voters, really sitting silently while something goes on? The ad doesn't say what is going on, but it must be something that is killing people. And we don't want people to die, do we? Of course not! Not while we can save them! And we can save them just by voting for Mr. Tyson. Right?

How does this political ad appeal to your emotions, rather than your intelligence?

_____________________________________________________________________


Examine this advertisement for dishwasher detergent. You may have noticed, if you have a dishwasher, that sometimes the glasses come out with little white spots on them. That's soap residue which didn't get rinsed properly in the cleaning process. Is it the end of the world? Apparently, according to this ad. In fact, having spots on your dishes is so terrible, it will cause you to lose your husband or boyfriend to another woman.

The thought of losing someone you love is a very serious, emotional thing. But are spotty dishes really going to make someone leave you? What do spotty dishes have to do with romance and love?

Sunlight soap could have just said, "Our soap is designed to dissolve better than other soaps, so you don't get spots." But it just doesn't have the same sort of urgency, does it? Advertisers want to play on your emotions in order to get your attention and convince you to buy their products, even when those emotions have nothing to do with the product itself.

Fallacies: Errors in logic

Invalid and unsound arguments are often used to trick, convince, persuade or confuse people. One place where this happens all the time is in advertising. Let's put the ad above into the form a logical argument.

This wig is natural looking.
No one will know your secret.
It is distinctively masculine.
It is comfortable and lightweight.
It fits in your pocket.
It is great for any occasion.
Therefore, you'll love it... so will she!!


Are the premises true? Why or why not?
Do they support the conclusion? Why or why not?

The advertiser doesn't really know you will love it. Maybe it will make your head itch. Maybe it will be hard to comb and clean. Most likely, people will be able to tell that it's not real hair.

This advertisement is neither a valid nor sound logical argument. It appeals to emotions. Specifically, older men's feelings and emotions, their fears that they are ugly if they lose their hair, that no one will love them if they are bald.

When someone tries to make an emotional appeal look like a logical argument, they are committing a FALLACY. A fallacy is a kind of error in reasoning. Fallacies should not persuade people, but they often do. Fallacies may be created intentionally (on purpose) in order to deceive other people, or they may happen unintentionally (by accident).

A fallacy is different from a FACTUAL ERROR. A FACTUAL ERROR is being wrong about the facts. A FALLACY is when the premises do not support the truth of the conclusion.

We will talk about several different fallacies, and give examples of them. Some fallacies pop up in certain places, such as advertising, religion, and politics.

Invalid arguments

All baseballs are round.
The moon is round.
Therefore, the moon is a baseball.

The president lives in the White House.
Barack Obama lives in the White House.
Therefore, Barack Obama is the president.


Arguments like these are not valid. They are called INVALID ARGUMENTS.

It's pretty obvious that the first example is wrong, because we all know that the moon is not a baseball! But this is not why the argument is invalid. It is invalid because the premises don't support the conclusion, not because its conclusion is obviously wrong.

The second argument might seem like a good one because we know the conclusion is true. Barack Obama is president right now. But you should always remember, in a valid argument the conclusion must be PROVEN by the premises.

Does the fact that Barack Obama lives in the White House prove he is president? No. Because Michelle Obama, his wife, also lives in the White House. And his daughters Sasha and Malia also live there. But they are not the president.

Examine the following invalid argument.

A peach is a type of fruit.
Peaches are yellow.
Therefore, all yellow fruits are peaches.


Can you explain why this is an invalid argument?

This may not seem like a big deal. After all, we all know that bananas are also yellow. So, who cares? The problem is when people make invalid and unsound arguments about important things, or when they try to trick you or persuade you about things that are not quite so obvious as baseball moons and yellow watermelons. This sort of persuasion happens every day, especially in things like advertising, retail stores, social issues, religion and politics.

Sound arguments

When we make an argument, we must try to make one that is not only VALID, (where the premises support the conclusion), but also SOUND. A sound argument uses premises that are actually true.

This argument is both VALID and SOUND. All premises are true and the conclusion follows from the premises:

Students in Ms. Rachel's class must stay inside for lunch when it rains.
It is raining today.
Anne is in Ms. Rachel's class.
So, Anne must stay inside during lunch.


This argument is VALID but UNSOUND:

All students love math.
Tara is a student.
Therefore, Tara loves math.


Is it true that all students love math? If you love math, you might assume this is true, based on your personal experience. But it's important to remember that personal experience can be incorrect. It may not apply to other people or other situations.

So, when you analyze an argument, you need to look at both the STRUCTURE (validity) of the argument, and also the TRUTH (soundness) of the premises.

Try these two arguments:


All flowers are plants.
No plants have feathers.
Therefore, no flowers have feathers.

All books are about boy wizards.
No boy wizards are named Harry Potter.
Therefore, there are no books about Harry Potter.


They both have the same structure, they are both valid, but one is sound and the other is not.

Which argument is sound?_________________________________________________

Why? _________________________________________________________________

Deductive arguments

A DEDUCTIVE ARGUMENT is an argument with premises that support or prove the conclusion. This is also called a SYLLOGISM (SILL-uh-jiz-uhm).

Tara has either a cat or a dog for a pet.
Tara does not have a dog.
Therefore, Tara must have a cat.


Can you identify the PREMISES in this argument?

1) ____________________________________________________________________


2) ____________________________________________________________________

What is the CONCLUSION?

__________________________________________________________________________


If all of the premises are true, and they support the conclusion, then the conclusion must be true. This is called a SOUND argument.

However, the premises don't have to be true for the argument to be VALID. This is a VALID argument:

All little girls are princesses.

Every princess has a fairy godmother.

All little girls have fairy godmothers.

By VALID we mean that the argument is well-structured, and the conclusion would have to be true based on the premises.

But do little girls really have fairy godmothers? No, of course not. The premises in this argument are not true. Yes, some little girls like to pretend to be princesses, but not all of them. And they're not really princesses. And fairy godmothers exist only in fairy tales.

This is an UNSOUND ARGUMENT because the premises are not true. But it is still a VALID argument because the conclusion would be correct, based on the premises.

So, it's important to remember that a VALID argument, one that seems logical and well-constructed, may still reach the wrong conclusion!

What is an argument?

When you think of an argument, you might think of two or more people who disagree about something. Sometimes there are strong feelings involved. Sometimes people who are arguing might raise their voices or someone might even start crying.

But we're not talking about that kind of argument. We're talking about a LOGICAL ARGUMENT, which is a little different. A logical argument is when PREMISES are used to prove or support a CONCLUSION.

Try this. Greta asks if you want to go see the movie “Ghost in the Fridge.” You make the following argument:

I don't like scary movies.

Ghost in the Fridge” is a scary movie.

Therefore, I won't like “Ghost in the Fridge.”

Can you identify the PREMISES in this argument?

1) ________________________________________________________________________

2) ________________________________________________________________________

What is the CONCLUSION?

__________________________________________________________________________


Or, how about this one:

If my room is not cleaned up by bedtime, I will be grounded.

My bedroom is not clean.

It is bedtime.

Therefore, I am going to be grounded.

Can you identify the PREMISES in this argument?

1) ________________________________________________________________________

2) ________________________________________________________________________

3) ________________________________________________________________________

What is the CONCLUSION?

__________________________________________________________________________