1. CRITICAL THINKING
• FALLACIES

2. WHAT ARE FALLACIES? AND WHY SHOULD WE
CARE?
• Like we’ve talked about, there are LOTS of people in our
lives that try to get us to believe what they say, and do
what they say.
• For example:
• Bosses
• Politicians
• Religious leaders
• Teachers
• But as critical thinkers, we have to question and challenge.
We have to say—wait—what are your arguments to get me
to believe what you want me to believe? What are your
arguments for getting me to do what you want me to do?
And are they SOUND or GOOD arguments?
• “Fallacies” are BAD arguments.
• They are TRICKY, because they SOUND like good
arguments. But they are FALSE and cannot be
believed
• Fallacies are used all the time. They are ways that
people—knowingly or not—try to get us to do
something or believe something, when there aren’t
good enough reasons to do so.

3. WHAT ARE FALLACIES? AND WHY SHOULD WE
CARE?
• So why should we learn fallacies?
• So—to quote the Who—we don’t get fooled again!
• And so that we avoid these mistakes OURSELVES!

4. WHAT IS A FALLACY?
• A VERY COMMON form of faulty argument
• Fallacies are “INVALID” arguments
• In other words, it DOESN’T MATTER if all the premises/supporting reasons are
true
• The premises JUST DON’T “ADD UP” TO THE CONCLUSION
• The conclusion JUST DOESN’T “FOLLOW” FROM THE PREMISES
Conclusion
Premises
Conclusion
Premises

5. HOW PEOPLE TRICK US WITH EMPIRICAL
GENERALIZATIONS: FALLACIES OF GENERALIZATION
• Hasty generalization (Chaffee, 2017, p. 466)
• This is when someone generalizes too quickly from limited experience.
• For example: “My last boyfriend was very needy. So I think all men are too needy!”
• Why’s this a fallacy?
• Because this person has made a generalization from too little information (one boyfriend).
Conclusion
Premises
Conclusion
Premises

6. HOW PEOPLE TRICK US WITH EMPIRICAL
GENERALIZATIONS: FALLACIES OF GENERALIZATION
• Sweeping generalization (Chaffee, 2017, p. 467)
• This is when someone uses good generalizations, but generalizes too far.
• For example: “Vigorous exercise contributes to overall good health. Therefore,
vigorous exercise should be practiced by recent heart attack victims, people who are
out of shape, and women who are about to give birth.”
• Why’s this a fallacy? Because this person is applying a generalization—exercise is
good—too broadly. Exercise IS good. But there are situations where it isn’t.
Conclusion
Premises

7. HOW PEOPLE TRICK US WITH EMPIRICAL
GENERALIZATIONS: FALLACIES OF GENERALIZATION
• False dilemma (Chaffee, 2017, p. 468)
• This is when people try to make us choose between ONLY two alternatives—although
there are many other alternatives!
• Example: “Either you love America, or you should leave it. And you obviously don’t
love America. So you should just leave!”
• Why’s this a fallacy? Because there are many more options than just two.
Conclusion
Premises

8. THE NEXT CATEGORY OF FALLACY IS THE CAUSAL
FALLACIES
• Common mistakes in arguments about what causes what
• The “Questionable Cause.” That’s when you claim a causal connection between
things when there is none
• In other words, you say one thing caused another when that’s really questionable.
• Example: “If you break a mirror, you will have seven years of bad luck. So you better
not break a mirror!”
• Why’s this a fallacy? Because there’s no reason to think that the mirror really is the
cause. Conclusion
Premises

9. THE NEXT CATEGORY OF FALLACY IS THE CAUSAL
FALLACIES
• Misidentification of the Cause. This is an argument that mixes up what causes
what.
• Example: “she’s an alcoholic, and she’s poor. So she must be an alcoholic as a result of
being poor!”
• Why’s this a fallacy? It’s not at all clear that one thing caused the other—or perhaps
both poverty and alcoholism were caused by some third thing!
Conclusion
Premises

10. HOW PEOPLE TRICK US WITH CAUSAL ARGUMENTS:
CAUSAL FALLACIES
• Post hoc ergo propter hoc:
• This is the fallacy that argues thing A caused thing B just because thing A came
BEFORE thing B.
• For example: “Before the shooting, the shooter played a lot of video games. So I bet
the video games caused him to do the shooting!”
• Why’s this a fallacy? Just because this person played a lot of video games is NOT
enough to prove that video games CAUSED the shooting.
Conclusion
Premises

11. HOW PEOPLE TRICK US WITH CAUSAL ARGUMENTS:
CAUSAL FALLACIES
• Slippery Slope: This is when someone argues that unreasonably terrible effects
will follow from a cause
• For example: “If I don’t get an A in this class, my friends will hate me, I’ll lose my job,
my boyfriend will break up with me, and so on. So I better get an A!”
• Why’s this a fallacy? There’s no good reason to think that not getting an A will cause
that whole chain of events.
Conclusion
Premises

12. FALLACIES OF RELEVANCE—ARGUMENTS BASED
ON IRRELEVANT PREMISES
• Fallacies of relevance are arguments based on irrelevant premises
• Appeal to authority:
• This is when someone argues on the basis of an authority—but the authority is irrelevant.
• For example: “Hi. You’ve probably seen me out on the football field. After a hard day’s work crushing
halfbacks and sacking quarterbacks, I like to settle down with a cold, smooth Maltz beer.”
• Why’s this a fallacy? Just because this person is an authority on football does NOT make them a reliable
authority on beer.
Conclusion
Premises

13. FALLACIES OF RELEVANCE—ARGUMENTS BASED
ON IRRELEVANT PREMISES
• Appeal to tradition: “It’s the way it’s always been”
• This is when someone’s argument for something is based on past traditions.
• Example: “Real men should never cry. How do I know that? Because that’s the way it’s
always been.”
• Why’s this a fallacy? Just because things have been done a certain way in the past
does NOT mean they should continue to be done that way! The future can be
different—and sometimes it should be!
Conclusion
Premises

14. FALLACIES OF RELEVANCE—ARGUMENTS BASED
ON IRRELEVANT PREMISES
• Bandwagon: “Everyone’s doing it!”
• This is when someone argues for something based on the fact that others are doing it
or believing it too.
• Example: “In the latest Gallup Poll, 86 percent of those polled believe that economic
recovery will happen in the next six months. So that must mean an economic recovery
is coming soon!”
• Why’s this a fallacy? Just because many people do or believe something does NOT
make it true or right. Conclusion
Premises

15. FALLACIES OF RELEVANCE, CONTINUED
• Appeal to fear: “I’m right, or else!”
• This is when someone argues you should do or believe something based on a threat.
• Example: “I’m afraid I don’t think you deserve a raise. After all, many people would be
happy to have your job at the salary you are currently receiving. I would be glad to
inter- view some of these people if you really think that you are underpaid.”
• Why’s this a fallacy? Just because someone is threatening to hurt us does NOT make
what they say or do true or right.
Conclusion
Premises

16. FALLACIES OF RELEVANCE, CONTINUED
• Appeal to ignorance: “I’m right, because no one has ever proved me wrong!”
• This is when someone’s argument ASSUMES the conclusion is right because it hasn’t been DISproven.
• For example: “Greco tires are the best. No others have been proved better.”
• Why is this a fallacy? The fallacy gets arguments exactly backwards. Remember, there are two parts of
any argument: a conclusion, and premises—or evidence or reasons—proving the conclusion is true.
• We should only believe things that are PROVEN right, things that have evidence to support them.
• This fallacy is a fallacy because it misses the point. It says, “I’m right, NOT because I have evidence, but
because you can’t disprove me!”
• But you only have a good argument IF and ONLY IF you have good evidence to support your argument.
Conclusion
Premises

17. FALLACIES OF RELEVANCE, CONTINUED
• Appeal to ignorance: “I’m right, because no one has ever proved me wrong!”
• ANOTHER example
• “Bigfoot exists. That’s because no one has ever proven otherwise!”
• Why is this a fallacy? The fallacy gets arguments exactly backwards. Remember, there are
two parts of any argument: a conclusion, and premises—or evidence or reasons—proving
the conclusion is true.
• We should only believe things that are PROVEN right, things that have evidence to support them.
• This fallacy is a fallacy because it misses the point. It says, “I’m right due to a LACK of evidence.”
That’s crazy!”
• But you only have a good argument IF and ONLY IF you have good evidence to support your
argument. Conclusion
Premises

18. FALLACIES OF RELEVANCE, CONTINUED
• Begging the question: Circular reasoning:
• This is an argument where the premises, or supporting evidence or reasons, already
assume the conclusion is true. In other words, it’s a circular argument:
• Example: “I know God exists. Why? Because God wrote the bible, and the bible tells us
so!”
• Why’s this a fallacy? Because my premises to prove God exists ALREADY ASSUME God
exists and wrote the bible! That’s circular reasoning.
Conclusion
Premises

19. FALLACIES OF RELEVANCE, CONTINUED
• Straw man: Misrepresenting another person’s argument, then attacking the misrepresentation
• This is an argument where I take someone else’s idea, dumb it down to be ridiculous, and THEN attack
it.
• For example, let’s say Bobbi and Toni are arguing. Bobbi things that the US military is receiving too
much funding, and a little more of the government money going to the military should go to education.
And this is how Toni responds: “So you want to completely defund the military, and eliminate the
military completely? That would just leave us open to terrorist attacks every day. Therefore, you’re
completely wrong—there should be no defunding of the military for education!”
• Why is this a fallacy? You can see, Toni completely misrepresented Bobbi’s point. Bobbi wans’t saying to
completely defund the military. But Toni misrepresented Bobbi’s point in order to attack it. That’s the
strawman fallacy.
Conclusion
Premises

20. FALLACIES OF RELEVANCE, CONTINUED
• Red herring: Leading someone off topic
• This is when someone’s argument goes off-topic. They use a premise or two that’s not
relevant to proving the conclusion.
• Example: “I’m definitely in favor of the death penalty. After all, overpopulation is a big
problem in our world today.”
• Why’s this a fallacy? Because overpopulation is a COMPLETELY separate issue from the
death penalty. The death penalty is about giving the ultimate punishment—death—to the
worst criminals. Overpopulation is about there being too many people on the planet.
Whether or not we should execute the worst criminals is different from the question of
overpopulation.” Conclusion
Premises

21. FALLACIES OF RELEVANCE, CONTINUED
• “Ad hominem”/Personal attack: “Your argument is wrong, because you’re a bad
person!”
• This is when someone argues AGAINST someone else’s argument by attacking that person
AS A PERSON—instead of examining whether or not their argument is good or bad.
• For example: “John thinks Peirce College should do more to help protect the environment.
But you can’t trust him. Don’t you know he’s a card-carrying communist? So let’s reject his
idea to do more for the environment!”
• Why’s this a fallacy? This person is attacking John’s character, saying he’s a communist. But
whether or not John is a communist has nothing to do with John’s argument about the
environment.
Conclusion
Premises

22. BE SURE TO GO OVER THE TEXTBOOK EXAMPLES
TO STUDY!
• Those examples are found on 478-491