Logical Fallacies - Introduction to the Philosophy of the Human Person.ppt

IPHP

1. Logical
Fallacies

2. What is logical fallacy?
•It is an error in logic that
can make a plausible, but
misleading argument.

3. Inductive Fallacies
•the result of incorrect use of
evidence.
Example:
“This chalk is white; therefore, all
chalks are white.”
(With inductive fallacies, an arguer leaps to a
conclusion based on insufficient evidence)

4. Deductive Fallacies
•the result of a failure to follow the
logic of a series of statements.
Example:
“All birds have beaks. A squid has a
beak. Therefore, a squid is a bird.”
(With inductive fallacies, an arguer makes an
incorrect or unsupported link between cause
and effect)

5. •While there are two main categories of
logical fallacies, it is important to note that
there is often overlap.
•Some fallacies may fit into both categories.
•However, it is important to note that logical
fallacies occur when:
a.An arguer incorrectly links cause and effect.
b.An arguer leaps to a conclusion based on
insufficient evidence.

6. •Prematurely jumping to a
presumptuous conclusion.
•Prejudices and superstitions are
the result of making a hasty
generalization.
1. HASTY GENERALIZATION

7. Ex: “There was a news story
about a guy in a fraternity who
was a rapist, so now I carry
mace if I know I’ll be going
anywhere near a frat house.”
How is this an example of the
Hasty Generalization logical
fallacy?

8. It’s a prejudiced point of
view. The arguer assumes that
because one person in a
fraternity is a rapist, all people in
fraternities are rapist. The arguer
is jumping to a presumptuous
conclusion about people in
fraternities.

9. Ex: “Last time I walked past a
black cat, I tripped and hurt my
arm, so now I avoid black cats
altogether.”
How is this an example of the
Hasty Generalization logical
fallacy?

10. It is a superstitious belief.
The arguer is assuming that the
cat caused her to initially injure
herself, so now she extends
that fear to all cats. She is
jumping to a presumptuous
conclusion about cats.

11. 2. FAULTY USE OF AUTHORITY
•Falsely recognizing someone
as an authority on something.
•Accepting someone’s
credentials without careful
evaluation.

12. How is this commercial example of the
Faulty Use of Authority logical fallacy?

13. The commercial assumes a
connection between the
specific celebrity’s popularity
and their authority on the
product or service they are
promoting.

14. 3. POST HOC or DOUBTFUL
CASE
•Assuming that because one
event follows another, the first
event is the cause of the
second.

15. Ex: “The rooster crows at 5:00
AM, and the sun rises at 5:00 AM;
therefore, the rooster makes the
sun rise.”
How is this an example of the
Post Hoc logical fallacy?

16. The arguer assumes that
simply because these two
events occur sequentially,
there is a cause and effect
relationship between them..

17. Ex: “A tornado hit my town after
a group of Satan worshippers
moved in, so God sent the
tornado to punish us for allowing
them to move here.”
How is this an example of the
Post Hoc logical fallacy?

18. The arguer assumes a
connection between the
Satan worshippers and the
tornado.

19. 4. FALSE ANALOGY
•Drawing an analogy or
comparison between two
situations that are totally
similar.

20. Ex: “An addiction to drugs or
alcohol can completely ruin
someone’s life. If you play too
many video games and get
addicted, you’re going to ruin
your life too.”
How is this an example of the
False Analogy logical fallacy?

21. The arguer assumes that
drugs or alcohol and video
games are analogous. She
assumes that a physical
addiction to a drug is probably
same in many ways of a
psychological addiction to
playing video games.

22. 5. AD HOMINEM
•Attacking a person’s character
rather than their statements.
•Latin for “to the man”

23. Ex: “Ernest Hemingway was an
alcoholic and a terrible father,
so I won’t read his books.”
How is this an example of the Ad
Hominem logical fallacy?

24. The arguer is attacking
Ernest Hemingway’s character
rather than his intellect output.

25. How is Michael Moore guilty of
the Ad Hominem logical fallacy
in this video?

26. Rather than attack George
W. Bush for his politics or his
ideas, he attacks his
character. Moore refuses to
make a distinction here
between George W. Bush’s
statements and his personal
habits.

27. 6. FALSE DILEMMA
•Posses an “either/or” situation by
suggesting that only two options are
possible.
•Sometimes called the “black/white
fallacy”

28. Ex: “If you don’t watch
basketball, you’re not a real
man.”
How is this an example of the
False Dilemma logical fallacy?

29. This statement poses an
“either/or” scenario in which a
person either watches
basketball (therefore making
them a “real man”)or that
person does not watch
basketball (in which case they
are not a “real man”)

30. Ex: “…here’s my first piece of
advice: you must learn to be a
problem solver not a problem
creator.”
-Bill O’reilly, Who’s Looking Out
For You?
How is this an example of the
False Dilemma logical fallacy?

31. Bill O’Reilly poses a
situation in which one is either
a “problem solver” or a
“problem creator” without
evaluating any middle ground
in between the two.

32. 7. SLIPPERY SLOPE
•Claiming that one event will trigger a series of
similar, undesirable events.
•If an arguer fails to provide evidence to support
his or her claim that one event will lead to a
similar, undesirable event, then they are guilty
of the “slippery slope” fallacy.

33. Ex: “Cloning animals should be
illegal because that would lead
to cloning humans, and then we
would have a race of clones.”
How is this an example of the
Slippery Slope logical fallacy?

34. The arguer assumes that if
cloning of animals is allowed,
then cloning of humans will be
too. Then, the arguer assumes
that his hypothetical cloning of
humans will grow out of
control.

35. Ex: “If they legalize marijuana,
then they will legalize heroin,
then they will legalize suicide,
then they will legalize murder.”
How is this an example of the
Slippery Slope logical fallacy?

36. The arguer jumps to the
conclusion that if marijuana is
legalized, then other
undesirable things will also be
legalized.

37. 8. BEGGING THE QUESTION
•A circular argument.
•When an argument makes a statement
that assumes that the very question
being argued is already answered.

38. Ex: “Women should not be
permitted into the men’s club
because the club is only for
men.”
How is this an example of the
Begging the Question logical
fallacy?

39. The arguer does not
adequately answer the
original question (“why
shouldn’t women be permitted
into men’s clubs?”). Instead,
the arguer treats the question
as if it has already been
answered.

40. Ex: “The reason everyone wants
the new “Slap Me Silly Elmo” doll
is because this is the hottest toy
of the season!”
How is this an example of the
Begging the Question logical
fallacy?

41. The arguer does not
adequately explain the
original issue (“the reason
everyone wants an Elmo”).
Instead, the arguer treats the
question as if it has already
been answered.

42. 9. STRAW MAN
•Setting up an extreme
example of an opposing view
to argue against.

43. Advocate: Self-driving cars are the
natural extension of active safety and
obviously something we should do.
Opponent: You just value new
technology over people's jobs. Switching
to self-driving cars will endanger driving
jobs in the transportation industry. Those
jobs are important to the economy and
the community.
How is this an example of the Begging
the Question logical fallacy?

44. Both positions are technically
correct, but the opponent's argument
has nothing to do with the advocate's
position. The opponent created a
straw man about the transportation
industry and claimed the advocate
prefers new technology, which is not
what the advocate said. If the
advocate then responds to the
comment about jobs, they have
allows the opponent to derail the
conversation.

45. Senator: I will vote to increase
the defense budget.
Public: Why don't you care
about education?
How is this an example of the
Straw Man logical fallacy?

46. The public has translated
the senator's support of more
money for defense as a lack of
support for education. But did
you see the senator mention
education at all? This straw
man argument can devolve
into a hasty generalization by
the public as well.

47. 10. TWO WRONGS MAKE A
RIGHT
•A rebuttal to an argument
which does not refute the
allegations, but simply
counterattacks.

48. Ex: “My stepdad says I’m
irresponsible, but I’m not.
Besides, he’s a jerk.”
How is this an example of the
Two Wrongs Make a Right logical
fallacy?

49. The arguer does not refute
the allegations that they are
irresponsible; instead, they
simply counterattack. The
arguer assumes that if the
stepdad is wrong, it justifies his
actions.

50. 11. NON - SEQUITUR
•A totally illogical connection
between cause and effect.

51. Ex: “Once rejected as
‘presposterous!’ Critics called it an
outrage! It aroused incredible
antagonism in scientific and literacy
circles. Yet half a million copies were
sold, and for twenty-seven years it
remained an outstanding
bestseller.”
How is this an example of the
Non – Sequitur logical fallacy?

52. The arguer assumes that
simply because this book
received a lot of publicity that
the book is a success. The
arguer falsely connects cause
and effect.

53. •If Jo loves to read, she must hate
movies. Jo hates to read, so she
must love movies.
•When it's sunny, I see my neighbor
walking his dog. He must only walk
the dog when the sun is out.
•Pierre is very talented. All
musicians are talented. Therefore,
Pierre is a musician.

54. •We don’t like to hire plumbers
because we’re from Alaska.
•People who eat eggplant are
healthy. I’m not healthy, so that
means I don’t eat eggplant.
•People who don’t study will fail
the test. Mira failed the test, so
therefore, she didn’t study.

55. •A pit bull attacked someone in
the news. My neighbor owns a
chihuahua. My life is in danger.
•All people can see. Eyes help
you to see. Therefore, all
people who have eyes can
see.