errare

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• errare
• humanum
• est
• (to err is human)

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FALLACIES
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INDUCTIONvs.DEDUCTION
PART 1
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INDUCTION

• (S ? G)
• think increase (induction, increase)
• from specific/particular instance or instances
• to generalization
• quantity () sufficient of items or people
  asked, sufficient data (stats)
• quality reliable source (authority), accurate
  in-depth observation
• PROBABILITY, not certainty

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INDUCTION

• BAD EXAMPLE
• You compare the prices of 4 textbooks at store 1
  with those at store 2 and notice that the prices
  are higher at the former than at the latter. You
  conclude that store 1 is more expensive.

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INDUCTION

• GOOD EXAMPLE
• A television documentary focuses on the issue of
  unwed teenage mothers in a particular city
  neighborhood. Four girls are interviewed and
  followed for several days. Then, a noted and
  respected sociologist who has studied thousands
  of unwed teenagers is interviewed, and she claims
  these four girls are representative of the many.

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INDUCTION

• INDUCTIVE FALLACIES
• wrong use of data
• insufficient sample (not enough people
  interviewed)
• ignore evidence (other possibilities)

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DEDUCTION

• (G ? S)
• think decrease (deduction, decrease)
• from inductive generalization
• to conclusion

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DEDUCTION

• 3 Propositions of a Deductive Syllogism
• 1) MAJOR PREMISE
• inductive generalization
• All
• All humans are mortal.
• (syllogism Greek, to calculate using logic)

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DEDUCTION

• 3 Propositions of a Deductive Syllogism
• 2) MINOR PREMISE
• statement about a specific member of that group
• This
• My English professor is a human.

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DEDUCTION

• 3 Propositions of a Deductive Syllogism
• 3) CONCLUSION
• Major Premise Minor Premise Conclusion
• 1 2 3
• S ? G, G ? S
• Therefore
• Therefore, my English professor is mortal.

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DEDUCTION

• IF the MAJOR premise absent or faulty induction
• IF the MINOR premise faulty observation
  concerning the individual at issue
• THEN conclusion faulty, invalid.
• HOWEVER, if the opposite is true, then the
  conclusion is a valid, strong one stronger than
  induction.
• CERTAINTY, validity, truth

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DEDUCTION

• BAD EXAMPLE
• A man is sitting opposite you on a train. He has
  what appears to be chalk dust on his fingers, and
  you conclude that he is a teacher.

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DEDUCTION

• BAD EXAMPLE
• Major premise All men with chalk on their
  fingers are school teachers.
• Minor premise This man has chalk on his
  fingers.
• Conclusion Therefore, this man is a school
  teacher.

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DEDUCTION

• BAD EXAMPLE
• Faulty Conclusion
• other occupations
• draftsmen, carpenters, tailors, artists, chalk
  maker
• coach, janitor, field crew, gymnast, father,
• other powders
• flour, confectioners sugar/powdered doughnut,
  talcum
• pixie dust, cocaine or heroin, anthrax or ricin
• sulfate of potash, chlorine, lye, powdered milk
• laundry detergent powder, hygiene powder,
  anhydrous salts

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DEDUCTION

• DEDUCTION INTRODUCTIONS
• Funnel Effect, Inverted pyramid
• G ? S
• syllogism, conclusion of syllogism thesis
  statement
• Major Premise - Generalization Reducing
  awareness of social differences is a desirable
  goal for the school.
• Minor Premise - Narrowing A uniform dress code
  would help to achieve that goal.
• Conclusion - Thesis Therefore, students should
  be required to dress uniformly.

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DEDUCTION

• DEDUCTIVE FALLACIES
• failure to follow the logic of a series of
  statements
• an error in one premise or both premises
• other possibilities exist that were not taken
  into consideration
• reliance upon support other than facts

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ENDPART 1