Logical Fallacies
Fallacies are errors in logic that weaken an argument. The following is a list of some of
the types of fallacies you may find in written or spoken arguments. The point is to avoid
committing one of these fallacies whenever possible. Carefully examine your speech to
make sure you haven’t relied heavily on these types of statements to make your
argument.
Term
Definition
Example
1. Begging the Question*
Assuming a notion is true
Shakespeare is the greatest writer
without proving it.
because people with good literary
Assuming the very premise taste prefer him. Ask anyone with
you’re trying to prove is
good literary taste who is the
true.
greatest writer and they’ll surely
say Shakespeare.
2. Undefined/Vague Terms
Use of blatantly broad,
vague terms that leave so
much room for definition,
they obscure the
argument.
Virtually no one cares about global
warming.
3. Undistributed Middle Term
A=B
C=A
C=B
Many border patrol officers take
bribes. Tim is a border patrol
officer. Therefore, Tim takes
bribes.
4. Circular Reasoning*
You imply a truth rather
than prove it by including
in your argument the
element of your proof.
I hate reading because books are
boring. I love my boyfriend
because he makes me feel happy
and in love.
5. False dilemma
Reducing the argument to
an overly simplified yes/no Are you with me or against me?
proposition.
America: love it or leave it.
6. Bandwagon appeal
Everybody else is doing it,
so you should too.
Everyone else is going to the party,
Mom!
7. Ad hominem argument
Attacking the messenger
rather than the message
How can you support
Schwarzenegger’s environmental
principles? Don’t you know he
drives a gas-guzzling SUV
8. Post hoc, ergo propter hoc
9. Non sequitur
10. False analogy
11. Red Herring
12. Straw Man
13. Appeal to pity
14. Appeal to fear
15. Appeal to false authority
16. Appeal to ignorance
After this; therefore,
because of this… (Because
A happened before B, A
caused B)
The argument does not
follow from the reasoning
indicated. There is a
step/link missing in the
argument.
She used to wear hats and now
she’s bald. Wearing hats causes
baldness.
Compares two elements
that are not equivalent to
make a conclusion about
one of the elements.
Distracting the reader
from the main issue;
throwing off track.
There’s no convincing evidence that
too much smoking is harmful. Too
much applesauce is harmful.
A claim is often a series of
arguments. If I take the
weakest link in a series of
arguments and refute only
that link, and then claim to
have refuted the entire
argument, I am guilty of
this diversionary tactic.
You should do this
because of my poor
condition.
In a 1952 speech, Nixon answered
the charge that he pocketed a
misappropriated “gift” of 18k by
telling a story of getting another
gift, a cocker spaniel puppy,
concluding defiantly, “Regardless of
what they say about it, we’re going
to keep it!”
I’m failing three of my classes right
now, and my parents are fighting
again; please don’t turn me in for
plagiarism.
If you don’t do this,
something bad might
happen to you.
Uses authority or
reputation to convince
others of an argument
unrelated to the nature of
authority.
Get enough fiber in your diet.
Don’t you want to see your
retirement years?
Steve Young promotes Toyotas, so
they must be the cars to buy.
Lack of proof of A proves
B.
Since you can’t prove St. John’s
Wart does harm, it must do good.
He’d make a great teacher because
he was always a great student.
Marijuana smoking is not that
harmful. I’d rather be in the car of
a driver influenced by marijuana
than alcohol.
17.Oversimplification
Eliminates the complexity
of the issue, other
explanations.
There can only be one explanation
18. Slippery Slope
Concluding a first step will
lead to a (usually
undesirable) final
outcome.
If we ban sawed-off shotguns,
soon, hunting rifles will also be
outlawed.
19. Hasty Generalization
Drawing a broad
conclusion based on little
evidence.
From what I’ve seen in the news,
Middle Eastern countries are all
very supportive of terrorist
networks.