Fun to play with and criticize
Terrible to actually use
What is a fallacy?
A false or mistaken idea; an often plausible argument using
false or invalid inferences
Qualities of Fallacies
Sometimes very persuasive
Hard to identify
Weaken an argument
Why is knowing about
fallacies important?
Knowing about them will make them easier to pinpoint in
your work as well as in others’ works
You automatically have the upper hand in a discussion if you
can provide strong evidence as well as be free from fallacies
4 Categories
Relations to others
Attacks on an individual
Poor and False Logical Development
Relations to Groups
Appeal to Authority/Testimonial:
Using a culture icon or someone with “authority” on the subject as
“evidence” for your argument
HP Computers
Appeal to Popularity/Bandwagon:
“Everyone’s doing it” - fear of rejection if you don’t join in…
“Four out of five dentists surveyed preferred Crest
toothpaste over the other leading brands.”
Advertisers who urge consumers to buy “the brand that's
number one” are using bandwagon appeal.
– Numbers may not exactly be true or skewed to appeal to
the consumer.
“Many people…” - general claim!
Attacks on the Individual
Ad Hominem/Personal Attack:
Making a personal attack on the individual instead of
arguing for themselves.
See this a lot in political ad campaigns
Mac vs. PC Windows Vista
Guilt by Association:
Assuming someone or something is not worth buying/trusting because
he/she/it is associated with a certain group of people
McCarthyism was a specific version of Guilt by Association in
which an individual, organization, or idea was associated in
some way with communism (civil rights supporter, etc.)
Poor and False Logical Development
Post hoc ergo propter hoc/False Cause:
Assuming. Since Event B followed Event A, then A must have caused B.
Statistics show that at beaches this past summer, ice
cream sales have gone up. So has the number of
people drowning in the ocean. Ice cream must be the
FRIENDS example
Limited Options/Either-Or:
Assuming there are only two sides to an argument or offering only
two choices
 “Either
she comes to my party or she’s not my real
Non sequitur/It does not follow:
A statement that does not follow logically or is
not clearly related to anything previously said.
 “Tens
of thousands of Americans have seen lights
in the night sky which they could not identify. The
existence of life on other planets is fast becoming
False Analogy/Comparison:
Using analogies often make poor evidence because the two things are not alike in
all aspects - the assumption is that two things are more alike than they really are.
Rolling socks makes you feel younger?!?!
Begging the Question/Circular Reasoning:
When the given argument depends on what it is
trying to support, and as a result, the argument in
question is being used to prove itself.
“Why did he do that? Did he have a reason?”
 “Of course he had a reason, or he wouldn’t have done it.”
Loaded Question:
Asking a question that assumes something that has not been proven yet - forces
an answer based on false or controversial premises.
“Do you know how fast you were going?”
 Answer yes: admit to speeding
 Answer no: admit not paying attention/speeding
Who Can Write the Worst Ad?
In groups, decide on a product. This could be something we all know
about, something made up, or even a person (think of political ads or
“changed” celebrities)
Must tell us: What the product is. Why we should all have/believe this
Create a visual ad. (Magazine spread? Billboard?)
Create a small speech for this product.
This speech must be LOADED with fallacies. At least 3
You will present your products to the class.
Be creative and have fun!