This document defines and provides examples of logical fallacies, which are flawed arguments that contain mistakes in reasoning. It divides fallacies into two types - fallacies of relevance, where the premises are irrelevant to the conclusion, and fallacies of insufficient evidence, where the premises do not provide enough support for the conclusion. Specific fallacies of relevance discussed include personal attacks, appealing to motives, and straw man arguments. Fallacies of insufficient evidence covered include appeals to authority, hasty generalizations, slippery slopes, and weak analogies.

1. Fallacies
4.0 What is a Fallacy?
• A (logical) fallacy is an argument that ccoonnttaaiinnss aa mmiissttaakkee iinn
rreeaassoonniinngg.
• Fallacies can be divided into two general types:
– FFaallllaacciieess ooff RReelleevvaannccee
Arguments in which the premises are logically irrelevant to the
conclusion.
– FFaallllaacciieess ooff IInnssuuffffiicciieenntt EEvviiddeennccee
Arguments in which the premises, though logically relevant to
the conclusion, fail to provide sufficient evidence for the
conclusion.
• 4.1 Fallacies of Relevance
• A statement is RREELLEEVVAANNTT to another statement if it provides at
least some reason for thinking that the second statement is true or
false.
• There are three ways in which a statement can be relevant or
irrelevant to another:

2. – A statement is positively relevant to another statement if it
provides at least some reason for thinking that the second
statement is true.
– A statement is negatively relevant to another statement if it
provides at least some reason for thinking that the second
statement is false.
– A statement is logically irrelevant to another statement if it
provides no reason for thinking that the second statement is
either true or false.
• 4.1 Fallacies of Relevance
• 4.1.1 Personal Attack
Example:
Professor Doogie has argued for more emphasis on music in our F2F
classes to facilitate creativity. But Doogie is a selfish bigheaded fool.
I absolutely refuse to listen to him.
• 4.1.2 Attacking the Motive
Example:
Donald Trump has argued that we need to build a new campus. But
Trump is the owner of Trump’s Construction Company. He’ll make a
fortune if his company is picked to build the new campus.
Obviously, Trump’s argument is a lot of self-serving nonsense.
• 4.1.3 Look Who’s Talking
Example:
Doctor: You should quite smoking.
Patient: Look who’s talking! I’ll quit when you do, Dr. Smokestack!

3. • 4.1.4 Two Wrongs Make a Right
Examples:
• “I don’t feel guilty about cheating on Zaid’s online quiz. Half the
class cheats on his quiz.”
• “Why pick on me, officer? Everyone else is using drugs.”
• 4.1.5 Scare Tactics
Example:
Diplomat to diplomat: I’m sure you’ll agree that we are the rightful
rulers of the Iraq. It would be regrettable if we had to send armed
forces to demonstrate the validity of our claim.
• 4.1.6 Appeal to Pity
Example:
Student to Lecturer: I know I missed half your classes and failed all my
quizzes and assignments. First my cat died. Then my girlfriend told
me she has found someone else. With all I went through this
semester, I don’t think I really deserve an F. Any chance you might
cut me some slack and change my grade to a C or a D?
• 4.1.7 Bandwagon Argument
Example:
All the really cool Taylors
students smoke cigarettes. Therefore, you should, too.

4. • 4.1.8 Straw Man
Example:
Singh and Karen are arguing about cleaning out their closets:
 Suzie: "We should clean out the closets. They are getting a bit
messy.“
 Singh: "Why, we just went through those closets last year. Do we
have to clean them out everyday?"
 Suzie: "I never said anything about cleaning them out every day.
You just want too keep all your junk forever, which is just
ridiculous."
• 4.1.9 Red Herring
Example:
"I think there is great merit in making the requirements stricter for the
graduate students. I recommend that you support it, too. After all,
we are in a budget crisis and we do not want our salaries affected."
• 4.1.10 Equivocation
Example:
In the summer of 1940, Londoners were bombed almost very night. To
be bombed is to be intoxicated. Therefore, in the summer of 1940,
Londoners were intoxicated almost every night.
• 4.1.11 Begging the Question
Example:
I am entitled to say whatever I choose because I have a right to say
whatever I please.

5. • 4.2 Fallacies of Insufficient Evidence
AArrgguummeennttss iinn wwhhiicchh tthhee pprreemmiisseess,, tthhoouugghh llooggiiccaallllyy rreelleevvaanntt ttoo tthhee
ccoonncclluussiioonn,, ffaaiill ttoo pprroovviiddee ssuuffffiicciieenntt eevviiddeennccee ttoo ssuuppppoorrtt tthhee
ccoonncclluussiioonn..
• 4.2.1 Inappropriate Appeal to Authority
Example:
My dentist told me that aliens built the lost city of Atlantis. So, it’s
reasonable to believe that aliens did build the lost city of Atlantis.
• 4.2.2 Appeal to Ignorance
Example:
Yoda must exist. No one has proved that he doesn’t exist.
• 4.2.3 False Alternatives
Example:
The choice in this MPP election is clear: Either we elect Zaki as our next
president, or we watch our MPP unity slide into anarchy and
frustration. Clearly, we don’t want that to happen. Therefore, we
should elect Zaki as our next president.
• 4.2.4 Loaded Question
Example:
Lee: Are you still friends with that loser Richard?
Ali: Yes.
Lee: Well, at least you admit he’s a total loser.

6. • 4.2.5 Questionable Cause
Example:
Effa gets a chain letter that threatens her with dire consequences if she
breaks the chain. She laughs at it and throws it in the garbage. On
her way to work she slips and breaks her arm. When she gets back
from the hospital she sends out 200 copies of the chain letter,
hoping to avoid further accidents.
• 4.2.6 Hasty Generalization
Example:
Malays are lazy. I have two friends who are Malays, and both of them
never prepare for class, or do their homework.
• Cont’d
• …occurs when one draws a general conclusion from a sample that is
biased or too small.
– Biased sample: I polled 100 professors from 100 schools, only
25% of them believed in peace. I guess most Malaysians don’t
believe in peace anymore.
– Too small of a sample: I asked my professors if they believed in
peace, and only one did. I guess professors don’t believe in
peace anymore.
• If it doesn’t have a “general conclusion,” then it’s not a
generalization .
– That biker with the swastika tattoo and brass knuckles will
probably beat me up if I talk to him.
– Since this argument draws a conclusion about one biker, and
not all (or most) of them, it is not a “generalization” at all.

7. • 4.2.7 Slippery Slope
Examples:
• “The Malaysian militarily shouldn't get involved in other countries.
Once the government sends in a few troops, it will then send in
thousands to die."
• 4.2.8 Weak Analogy
Example:
Nobody would buy a car without first taking it for a test drive. Why then
shouldn’t two mature UiTM students live together before they
decide whether or not to get married?
• Cont’d
• …occurs when an arguer compares two (or more) things that aren’t
really comparable in the relevant respect.
– e.g., Lettuce is leafy and green and good on burgers. Poison
Ivy leafy and green. It would be good on burgers too.
• Common forms:
– A has characteristics w, x, y and z. B has characteristics w, x and
y. Therefore, B probably has characteristic z too.
– A is x and y. B is x and y. C is x. So C is y.
• Many exceptions:
– Alice lives in a mansion and she is rich. Bruce lives in a
mansion. Bruce is probably rich too.
• The form is easy to spot, but—quite often—to know whether it is
fallacy or not, you just have to know whether the shared
characteristics are relevant to the concluded one.

8. • 4.2.9 Inconsistency
Example:
Note found in a Forest Service Suggestion box: Park visitors need to
know how important it is to keep this wilderness area completely
pristine and undisturbed. So why not put up a few signs on the
trees to remind people of this fact?
References
BBooookk
• Chapter 5 (Logical Fallacies -1) & 6 (Logical Fallacies -2): G
Bassham, W Irwin, H Nardone, J M Wallace, Critical Thinking: A
Student's Introduction, McGraw-Hill International Edition, 2007
OOnnlliinnee RReessoouurrcceess
• Fallacies (The Nizkor Project):
http://www.nizkor.org/features/fallacies/
• Cool Optical Illusions: http://www.coolopticalillusions.com/