Old Fallacies, Emotional Fallacies, Groupthink
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HW Due
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Quiz!
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Review Quiz!
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Fallacies Review
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New Emotional Fallacies
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Fallacies and evaluating arguments
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For Next time: Read Chapter 4: 104-113
Quiz!
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Diagram the structure of the argument below:
On the basis of [1] and [2], [3]. Since [3], [4]. [5]
also implies [4]. Because [4] and [6] we can deduce
[7].
Quiz!
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Diagram the structure of the argument below. Number the
claims ( ex- [1] = philosophy is awesome) and then draw the
argument diagram.
What's the best way to avoid making bad decisions? Taking
a critical thinking course will probably be most effective
because it makes you aware of potential cognitive biases
that can influence your choices. On top of that, it helps you
understand the difference between a good argument and a
bad argument and if you understand that then you can avoid
making bad decisions.
Quiz!
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Which, if any, of the following terms below are
vague:
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(a) Philosophy 202: Critical Thinking
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(b) Enormous
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(c) Applesauce
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(d) Premeditated
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(e) Boring
Quiz!
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The inference being made below is an example of
what fallacy (mistake in reasoning)?
The lifespan of the average Chihuahua is about 15
years so I can expect Pepe, my new Chihuahua, to
live until around 2026.
Quiz!
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Rewrite the sentence below to remove as much
ambiguity as possible. In a second sentence, explain
why you resolved the ambiguity in the specific way
that you did.
Flying planes can be dangerous
Fallacies
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We have already mentioned fallacies quite a bit
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Fallacies, we said, are common mistakes in thinking
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Fallacies can seem really convincing but we should try
to avoid them
The presence of a fallacy in an argument should give
us reason to question its soundness (if deductive) or its
strength (if inductive)
Can you give me any examples of fallacies we've
already looked at?
Familiar Fallacies
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Fallacy of Composition
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Fallacy of Division
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Assuming groups share the same properties as its
members
Assuming members share the same properties as the
group
The Planning Fallacy
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Neglecting past experience with familiar tasks when
making predictions about task duration or difficulty
More Familiar Fallacies
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Ad Hominem
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Responding to an argument by criticizing its source
instead of by responding to the claims found in it
Begging the Question
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We mentioned arguments that beg the question last
time during our discussion of problems that sometimes
arise when we use definitions
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How did we define begging the question again?
Begging the Question
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Begging the question: when you assume the truth of
your conclusion at the outset of an argument
It is a mistake in reasoning to presume that your
argument will be successful
For example:
“Affirmative action can never be fair or just because
you cannot remedy one injustice with another
injustice.”
Begging the Question: another example
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*Dinosaur Comics http://www.qwantz.com/index.php
Ad Hominem
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We mentioned Ad Hominem during our discussion of
cognitive biases
Recall that we said that many fallacies can be the result
of cognitive biases
Ad Hominem attacks, for example, may stem from
belief bias (I disagree with you therefore you must be
wrong) or from negativity bias (I don't like you so you
must be wrong)
In each case, it is a mistake to assume that the source of
an argument is necessarily relevant to its content
Ad Hominem: Examples
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(A): If we hit the beach at 6am
then we should just be hitting
high tide so the surf should be
good
(B): You were never really
good at making decisions,
you're probably wrong about
this
The problem with Ad
Hominem attacks is that they
leave the actual argument
entirely untouched
A Word of Warning
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Ad Hominem always involves a personal attack but not every
instance of a personal attack in an argument is an instance of
Ad Hominem
You commit the fallacy of Ad Hominem only if the attack is
meant as a direct response or counter-argument to a claim
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For example:
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(A): It's raining outside right now
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(B): Look outside, it's not raining you idiot.
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In this case (B) is being mean but not resorting to Ad
Hominem
Scapegoating
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Scapegoating is a fallacious kind of emotional
fallacy
To scapegoat is to assume that one individual or
group is responsible for a complex issue
It is almost always unlikely that such an individual is
truly entirely responsible in the way implied
For example: “Obama has ruined this country” or
“Religion is responsible for most of the world's
problems”
Scapegoating
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Scapegoating is a mistake in reasoning (a fallacy)
because it proposes a simplistic solution to what is
likely a complex problem
Scapegoating is also one of the most popular and
common fallacies committed (especially in political
rhetoric)
Scapegoating is also often the result of several of the
cognitive biases we've already looked at: belief bias,
negativity bias, framing effects
Red Herring
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We commit the Red Herring fallacy when we introduce
information that is irrelevant to a claim as if it were relevant
For example:
(A): I think I could probably graduate more quickly if I took
4 classes this quarter instead of 3
(B): College is a waste of time and you go into so much that
debt that it's not even worth it
The information introduced by (B), even if true, is entirely
irrelevant to (A)'s claim even though they both seem to be
speaking about the same thing
Why care?
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Next week we are going to go beyond reconstructing
arguments and begin to evaluate them
Being able to spot mistakes in reasoning or problems
with vagueness or ambiguity in a claim can make a big
difference in how an argument is evaluated
Some arguments will only appear valid (remember Spot
the reptile) but in fact be invalid
Some inductive arguments may appear superficially
strong but contain fallacies that expose their weaknesses
For Next Time
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Read Chapter 4: 104-113