Text Table of Contents #4:
What are the Reasons?
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Arguments intend to convince us to accept a
conclusion – i.e., a position, claim, belief, etc.
Why does the author want us to accept this
conclusion?
Reasons tell us why that conclusion should be
accepted.
Will Ferrell
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For each sentence ask:
◦ Does this sentence support the conclusion?
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Or does it make sense when you precede
the sentence with:
◦ The conclusion is true because …
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Reasons + Inferences  Conclusion
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The acceptability of a conclusion depends on
◦ the quality of the reasons (evidence)
◦ the validity of the inferences (logic)
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Should the public be shown actual courtroom trials on television?
It seems as though the system can easily be corrupted by having
cameras in the courtroom.
Victims are hesitant enough when testifying in front of a small
crowd, but their knowledge that every word is being sent to
countless homes would increase the likelihood that they would
simply refuse to testify.
There is little to no assumed innocence for the accused when their
trial is put on television.
People do not watch court television because they are concerned
about our country’s ability to effectively carry out the proceedings
of the judicial system; instead, they are looking for the drama in
witness testimony: entertainment.
Thus, leave the cameras out of the courtrooms, and let the public
view sitcom drama based on the legal system.
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Issue: Should court trials be televised to the
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Conclusion: Do not televise court trials.
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R1: Televising corrupts judicial system.
public?
◦ SR1a: Fewer victims will testify.
◦ SR1b: Presumed innocence will disappear.
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R2: Public wants drama in witness’ testimony
(i.e., entertainment) – not judicial process.
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Infer  deduce or conclude (information) from evidence and
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Validity of inference
reasoning rather than from explicit statements (Oxford dictionary)
◦ does not refer to truth of premise or conclusion
◦ refers to the form of the inference
◦ i.e., how the inference is drawn
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A word about inference - induction vs. deduction
 induction – results in probable conclusion
 deduction results in certain conclusion
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All fruits are sweet.
A banana is a fruit.
Therefore, a banana is sweet.
For the conclusion to be necessarily true, the
premises need to be true.
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Leading from true premises to a false
conclusion.
All apples are fruit. (correct)
Bananas are fruit. (correct)
Therefore, bananas are apples. (incorrect)
Do you understand why this argument is
invalid?
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When a valid argument is used to derive a false
conclusion from false premises, the inference is
valid because it follows the form of a correct
inference.
A valid argument with false premises may lead to
a false conclusion:
◦ All tall people are Greek. (incorrect)
◦ John Lennon was tall. (correct)
◦ Therefore, John Lennon was Greek. (incorrect)
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Do you understand why this argument is valid?
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A valid argument can also be used to derive a
true conclusion from false premises:
◦ All tall people are musicians (incorrect)
◦ John Lennon was tall (correct)
◦ Therefore, John Lennon was a musician (correct)
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Do you understand why this argument is valid?
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Facts, examples, analogies, statistics,
authorities, etc.
Observations, beliefs, principles
Later we will explore more thoroughly how to
evaluate the quality of evidence