lecture 2 s 10 de & inductive logic

lecture 2 s 10 de & inductive logic - BASIC LOGICAL...

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BASIC LOGICAL CONCEPTS Task: distinguish good arguments from bad. Two questions: Are the premises true? Do the premises provide good reasons to accept the conclusion?
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TWO ARGUMENT TYPES Deductive arguments (try to) PROVE their conclusions Inductive arguments (try to) show that their conclusions are PLAUSIBLE OR LIKELY .
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DEDUCTIVE ARGUMENTS Some pigs have wings. All winged things sing. Therefore some pigs sing. Everyone has one and only one biological mother. Full sisters have the same biological mother. No one is her own biological mother. Therefore there is no one whose biological mother is also her sister. : Solve the mysteries
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INDUCTIVE ARGUMENTS Every ruby discovered thus far has been red. So, probably all rubies are red. Polls show that 87% of 5-year-olds believe in the tooth fairy. Marta is 5 years old. Marta probably believes in the tooth fairy . Chemically, potassium chloride is very similar to ordinary table salt (sodium chloride). Therefore potassium chloride tastes like table salt.
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THE DIFFERENCE ,FZ : deductive / inductive If the premises are true the conclusion necessarily / probably is true. It is impossible / unlikely for the premises to be true and the conclusion to be false. It is logically inconsistent / consistent to assert the premises but deny the conclusion.
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FOUR TESTS Four tests allow us to identify deductive/inductive arguments The indicator word test The strict necessity test The common pattern test The principle of charity test
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INDICATOR WORD TEST Deduction Induction Certainly Probably Definitely Likely Absolutely Plausible Conclusively Reasonable This entails that The odds are that
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Arguments may not contain any indicator words. Pleasure is not the same thing as happiness. The occasional self-destructive behavior of the rich and famous confirms this far too vividly.
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This note was uploaded on 09/08/2010 for the course LING 21 at San Jose State University .

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lecture 2 s 10 de & inductive logic - BASIC LOGICAL...

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