Logical fallacies - Curriculum
Logical fallacies - Curriculum
Logical fallacies - Curriculum
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Errors in Logic Often Found in<br />
Persuasive Texts
A fallacy is an error in logical reasoning in an<br />
argument or a persuasive text.<br />
This isn’t the same as a “factual error.”<br />
FALLACY<br />
FACTUAL ERROR<br />
4 out of 5 dentists<br />
recommend Chewy Brand<br />
Gum<br />
Chewing gum is made out<br />
of Silly Putty
There are many different types of <strong>fallacies</strong>,<br />
and readers should be able to identify <strong>fallacies</strong><br />
when they occur in text.<br />
Hasty<br />
Generalization<br />
Ad Hominem<br />
Exaggeration<br />
Appeal to<br />
Authority<br />
Post Hoc<br />
Appeal to<br />
Emotion<br />
Begging the<br />
Question
One of the most common forms of fallacy is<br />
called an ad hominem argument. Literally, ad<br />
hominem means “against the person.”<br />
Instead of using logic in an argument, sometimes<br />
people attack their opponent. That’s effective,<br />
but fallacious!
EXAMPLE:<br />
Teacher: Education is important.<br />
We should spend more to improve<br />
our schools.<br />
Student: Of course you think that.<br />
You’re a teacher.
Another common fallacy is the Hasty<br />
Generalization. That’s when a person makes<br />
sweeping statements based on just a little<br />
evidence.<br />
Example: Every swan I’ve ever seen was white.<br />
Therefore, all swans<br />
must be white.
Sometimes the breakdown in logic is just funny...
A post hoc fallacy involves attributing a cause<br />
and effect relationship without adequate<br />
evidence. (Which is similar to a hasty<br />
generalization.)<br />
Example: My car was running fine until Jimmy<br />
borrowed it. Now it makes a funny noise. He<br />
must have done something to it.
One of the most common <strong>fallacies</strong> that comes up<br />
in advertising is the Appeal to Authority. Just<br />
because somebody famous has an opinion, that<br />
doesn’t make it true!
Similarly, just because a doctor or a dentist says<br />
something, that doesn’t make it true, either!
This is also called the Bandwagon Fallacy,<br />
because people are encouraging you to “jump on<br />
the bandwagon.” Everybody else is doing it! All<br />
the cool kids are doing it! Don’t you want to be<br />
like everybody else?
Is there a fallacy in this argument?<br />
I was sick with a terrible cold for<br />
several days. Then I took some<br />
vitamin C, and I got better.<br />
Therefore vitamin C is a cure for<br />
colds.
Is there a fallacy in this argument?<br />
I was sick with a terrible cold for<br />
several days. Then I took some<br />
vitamin C, and I got better.<br />
Therefore vitamin C is a cure for<br />
colds.<br />
This is a post hoc fallacy. If you’ve been sick for several days, you<br />
probably would have gotten better soon anyway!
Is there a fallacy in this argument?<br />
Fox News criticized a recent report<br />
on climate change, saying that they<br />
did not report their numbers<br />
accurately. But then, you’d expect<br />
Fox News to find a way to attack<br />
the research on climate change.
Is there a fallacy in this argument?<br />
Fox News criticized a recent report<br />
on climate change, saying that they<br />
did not report their numbers<br />
accurately. But then, you’d expect<br />
Fox News to find a way to attack<br />
the research on climate change.<br />
This is a classic ad hominem attack! Just because Fox News has a bias<br />
doesn’t mean they’re wrong!
Is there a fallacy in this argument?<br />
My opponent in this election has<br />
suggested that cutting business<br />
taxes could improve the economy.<br />
Do I really need to point out that<br />
big businesses have paid for his<br />
campaign?
Is there a fallacy in this argument?<br />
My opponent in this election has<br />
suggested that cutting business<br />
taxes could improve the economy.<br />
Do I really need to point out that<br />
big businesses have paid for his<br />
campaign?<br />
This is another ad hominem attack. Getting money does not<br />
automatically make a person wrong!
Is there a fallacy in this argument?<br />
Four out of five dentists who chew<br />
gum recommend Trident.
Is there a fallacy in this argument?<br />
Four out of five dentists who chew<br />
gum recommend Trident.<br />
A classic appeal to authority. And how many dentists who DON’T chew<br />
gum would recommend Trident?
Is there a fallacy in this argument?<br />
Grades in school don’t mean<br />
anything. Benny is an idiot, and he<br />
makes straight-As!
Is there a fallacy in this argument?<br />
Grades in school don’t mean<br />
anything. Benny is an idiot, and he<br />
makes straight-As!<br />
A hasty generalization. There may be a lot of reasons why Benny<br />
makes good grades.
Is there a fallacy in this argument?<br />
There’s nothing wrong with<br />
speeding. Everybody does it!
Is there a fallacy in this argument?<br />
There’s nothing wrong with<br />
speeding. Everybody does it!<br />
An appeal to popularity. If all your friends were jumping off a bridge,<br />
would you do that too???
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