Transcript Class #6 - 7/13/15

Philosophy 1100
Title:
Critical Reasoning
Instructor:
Paul Dickey
E-mail Address: [email protected]
Website:http://mockingbird.creighton.edu/NCW/dickey.htm
Today:
Second Editorial Analysis Due
--- Instant Democracy is Never Doable
Discuss Midterm Exams & Re-do (In 2 weeks)
Final Essay: Do You Have Any Questions?
Discussion on Chapter Six & Seven
Next Week:
Portfolio Assignment #5
Read Chapter Nine, pp. 243- 251, 255-270,
pp.272-274
Exercise 9-2, odd numbered problems.
1
Portfolio
Assignment #5
What is Rhetoric?
·
“Collect” 2-3 artifacts that illustrate
different forms of rhetoric. For each, write a
description of the artifact selected, identify the
form of rhetoric, and explain why this is an
example of that particular form.
· What are Logical Fallacies?
·
“Collect” 2-3 artifacts that illustrate
different logical fallacies. For each, write a
description of the artifact selected, identify the
type of logical fallacy it is, and explain why this
is an example of that particular logical fallacy.
Logical Fallacies
3
Psychological & Related Fallacies
•
Logical fallacies pretend to give an argument with
a premise and conclusion, but the premises do not
support the conclusion and typically only evoke
emotions that make us “want” to believe or “satisfy”
some pre-judgment.
•
There are of course many different kinds of logical
errors. There are some recurring patterns of these
that are found so frequently that they have been
characterized and defined as common “logical
fallacies.”
•
Thus, a logical fallacy is a particular type of logical
error that occurs frequently and can be understood
in terms of general characteristics or in the form of
the supposed argument.
4
Chapters Six & Seven:
Logical Fallacies
CHAP 6:
Amber: Argumentum Ad Hominem
Tim: The Straw Man / False Dilemma
Cassandra: Misplacing Burden of Proof / Begging the Question
Jessica: Appeal to Emotion
Derek: Irrelevant Conclusions / Slippery Slope
CHAP 7:
Jordan: Generalizations
Dana: Weak Analogy
Instructor: Fallacious Appeals to Authority, Popularity, Cause &
Effect; Untestable Explanations
In your presentation, you must define your fallacy
type, give examples, and distinguish it from other
logical fallacies that are similar. I encourage you to
use Power Point slides in your presentation if
possible, but it is not necessary.
5
Chapter Six:
Relevance Fallacies
(Red Herrings)
6
More Dirty Tricks & Not Playing Fair
•
A Red Herring occurs when a topic or
claim is introduced that is irrelevant to the
claim at issue with the intent only of
distracting the argument.
Cowgirl: “The animal rights people shouldn’t
pick on rodeos. They should all come see how
much fun all the kids are having. And those
dudes who ride the bulls. Are they hot or what?
Important Video
7
More Dirty Tricks & Not Playing Fair
•
Similarly, a smokescreen is when
topics or claims are introduced that
are irrelevant to the original issue
with the specific intent to make the
issue appear to be too complex or
complicated to resolve.
•
So, trying to “clarify” a vague
argument by “giving all the facts you
have” may indeed be the absolutely
WORST thing you can do.
8
The Ad Hominem Fallacy
•
Maybe the most common of all logical mistakes.
•
The Ad Hominem Fallacy mistakes the qualities of the
argument itself with the the person or personality of the
individual making the claim.
“BOB: Reality consists of more than just what can see and feel.
God is real.
BIKER: “If you weren’t so removed from reality, I might be more
inclined to discuss it with you.”
Want more advanced stuff on topic? Click here
9
The Ad Hominem Fallacy
•
Most ad hominem arguments are negative and
typical examples of ad hominem arguments will
be negative, but not always.
• e.g. Heather is very nice and is always a very positive
person, so if she is opposed to the war in Iraq, there
must be something terribly wrong with it.
•E.g. Ms. Gullible: “The Jehovah Witnesses that come
to the door always seem to be the “sweetest” people so
there must be something to what they believe.”
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The Personal Attack Ad Hominem
•
Say you twist the example about Heather around.
• e.g. My boss is a very negative person, so
although he is opposed to the war in Iraq, that
means nothing. He is against everything.
Video
• e.g. remember Rush Limbaugh in the video:
“If you are going to start agreeing with Rosie
O’Donnell, I would suggest rehab and
treatment.” (Ridicule & Sasrcasm)
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Specific Forms of Ad Hominems
•
The Inconsistency Ad Hominem suggests erroneously that if
one can show that a person has made contradictory claims
at different occasions, then the claims are thereby refuted,
e.g. Hilary can’t be right that Obama is ready to be
president as she is saying now. She said exactly the
opposite during her political campaign.
•
The Circumstantial Ad Hominem suggests erroneously that
if one’s claim is associated to the claimant’s circumstances
in life, then the claim is refuted e..g. Of course, Sen. Nelson
is for farm subsidies. He is from Nebraska.
•
Poisoning the Well occurs when an ad hominem is issued
prior to allowing someone to make their argument.
Interestingly, a speaker might have “the well poisoned
against her” by the opponent making a denial of something
unsavory about her, such as “Hilary may not be a bleeding
heart liberal, but….”
Video
12
The Genetic Fallacy
•
The Genetic Fallacy suggests erroneously
that a claim is refuted by disputing its origin or
history.
• e.g. The constitution is a bogus document
since it was primarily written with the intent to
protect the property of the wealthy.
• e.g. God does not exist because the whole
idea of God originated with superstitious
people who had no knowledge of science or
the universe.
Want more advanced stuff on topic? Click here
13
Misplacing/Shifting
the Burden of Proof
•
The burden of proof in an argument rests on the person
making the claim. It is her responsibility to give the
premises and the reasons to believe her claim is true.
•
To try to shift the burden of proof onto the person who is
listening to your argument and trying to make him show
that you are wrong is called misplacing the burden of
proof.
•
A particular example of this logical error is the appeal to
ignorance which suggests that we should believe
something because no one has proven or shown it to be
wrong.
•
Another example is when a proponent of a claim
suggests that his position is right because you haven’t
give a good argument for the opposite claim.
Video
Want more advanced stuff on topic? Click here
14
The Burden of “Proof”?
(But Mr. Dickey, you said ….)
•
BE VERY CAREFUL!
•
This terminology is misleading and seems to
confuse the issue that we clarified in class earlier
about proof and evidence.
•
Even if you agree to allow someone to say “proof”
when they really mean evidence, be sure that you
are clear about the difference between the forms of
support in deductive and inductive arguments..
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Begging the Question
•
Circular Argument / “Petitio Principii”
•
To "beg" the question is to ask that the very point at
issue be conceded, which is of course illegitimate.
•
That is, you are assuming your conclusion as a
premise.
•
How does it differ from a valid, deductive
argument?
•
Be careful of a very common misuse of the term in
which one confuses “begging the question” with
“brings up the question.”
16
Chapter Seven:
Induction Fallacies
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Generalizations
•
Inductive generalization Fallacies occur when too
little support is given to make the claim
reasonable. Various ways this is done is:
1. Hasty Generalization, or Arguing from
an insufficient number of cases, e.g.
The argument from anecdote. .
2. Generalizing from Exceptional Cases, e.g.
The Fallacy of Biased Sample or the Selfselection Fallacy
•
3. Accident. Assuming a general principle has to
apply to every given circumstance.
18
Chapter Nine
Deductive Arguments:
Categorical Logic
Categorical Logic
•
Consider the following claims:
1. Everybody who is ineligible for Physics 1A
must take Physical Science 1.
2) No students who are required to take
Physical Sciences 1 are eligible for Physics 1A.
•
Are these different claims or the same claim?
•
Categorical logic is important because it gives us
a tool to work through the confusion with a
technique to answer that question clearly.
•
Such is done through the use of standard logic
forms.
Categorical Logic
•
Categorical Logic is logic based on the
relations of inclusion and exclusion
among classes.
•
That is, categorical logic is about things
being in and out of groups and what it
means to be in or out of one group by
being in or out of another group.
Four Basic Kinds of Claims in
Categorical Logic
(Standard Forms)
A:
All _________ are _________.
(Ex. All Presbyterians are Christians.
E:
No ________ are _________.
(Ex. No Muslims are Christians.
___________________________________
I:
Some ________ are _________.
(Ex. Some Arabs are Christians.
O: Some ________ are not _________.
(Ex. Some Muslims are not Sunnis.
Four Basic Kinds of Claims in
Categorical Logic
What goes in the blanks are terms. In the
first blank, the term is the subject. In the
second blank goes the predicate term.
A:
All ____S_____ are ____P_____.
(Ex. All Presbyterians are Christians.
Venn Diagrams
Categorical Logic
The Four Basic Kinds of Claims in Categorical
Logic can be represented using Venn Diagrams.
(See page 256 in textbook.)
The two claims that include one class or part of a
class within another are the affirmative claims (I.e.
the A-claims & the I-Claims.
The two claims that exclude one class or part of a
class from another are the negative claims (I.e.
the E-claims and the O-claims.
The Bottom Line?
Translating Claims into Standard Form for Analysis
•
Two claims are equivalent claims if, and
only if, they would be true in all and
exactly the same circumstances.
•
Equivalent claims, in this sense, say the
same thing.
•
Equivalent claims will have the same
Venn Diagram.
Some Tips
1.
The word “only” used by itself, introduces the
predicate term of an A-claim, e.g.
“Only Matinees are half-price shows” is to
be translated as “All half-price shows are
matinees”
2.
The phrase “the only” introduces the subject
term of an A-claim, e.g
Matinees are the only half-price
shows” also translates to “All half-price
shows are matinees.”
3.
Claims about single individuals should be
treated as A-claims or E-claims, e.g.
“Aristotle is left-handed” translates to either
“Everybody who is Aristotle is left handed”
or “No person who is Aristotle is not lefthanded.”