批判性思维第八章PPT课件

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Pay attention to the following problems with testimonials:
selectivity personal interest Omitted information the human factor
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Chapter 8
How good is the evidence: intuition, personal experience, testimonials, and appeals to authority?
by雷玲、孙杰
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The Need For Evidence
We encounter many conclusions , reasons, or assumptions, but we don’t know whether they are dependable. We need evidence to prove whether they are true or false.
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Personal Testimonials as Evidence
“ All my friends are saying about the new phone. I should buy same quality.”
How helpful is such evidence? Usually, not so good until we find out much more about the experience, interests, values, and biases behind them.
Frequently use of headphones may cause hearing loss.
recent crime statistics report an increase in the number of gun related crimes over the last 10 years.
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Locating factual claims (P.105)
We encounter factual claims as (a) descriptive conclusion, (b) reasons used to support either descriptive or prescriptive conclusion, or (c) descriptive assumption. Examples :
fuel. 2020/10/13
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Sources of evidence
intuition
personal experience
testimonials
appeals to authorities
personal observations
case examples
research studies
We must be very wary of claims backed up only by intuition.
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Dangers of appealing to personal experience as evidence
“I cross the street all the time without looking, and I have never been hit by a car. Therefore I do not see the need to look both ways before crossing.”
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How to determine dependability?
These questions: What is your proof? Where is the evidence? Are you sure that’s true? How do you know that’s true? Why do you believe that? Can you prove it?
The greater the quality and quantity of
evidence supporting a claim, the more we
can depend on it, and the more we can
call the claim a “fact”.
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2020/a10/n13alogies
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Intuition as evidence
When we use intuition to support a claim, we rely on “common sense”, or on “gut feelings”, or on hunches.
A major problem with intuition is tha0/10/13
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Appeals to authority as evidence
The monetary costs of switching to hybrid cars and
alternative energy sources are far less than the
political benefits to decreasing dependency on fossil
Personal experience often lead us to commit the hasty generalization fallacy.
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Exceptions:
When an experienced pilot has an intuition that the plane doesn't feel right as it taxis for takeoff. Sometimes such “hunches” are not blind.