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P160 hempelhume

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• 1. PHIL 160 &quot;Induction & Confirmation&quot; PHIL 160
• 2. LEARNING OBJECTIVES: PHIL 160 Strategy for theorizing & testing Role of deduction Role of induction Problem of induction
• 3. PHIL 160 meaningful claims are testable Verifiability theory of meaning:
• 4. SENTENCES IN SCIENTIFIC THEORIES PHIL 160 SENTENCES DESCRIBING EXPERIENCE logical relation that counts as support
• 5. PHIL 160 True assumptions guarantee true conclusion. DEDUCTIVE LOGIC
• All men are mortal.
• Socrates is a man.
•  Socrates is mortal.
• 6. PHIL 160 True assumptions support (not guarantee) true conclusion. INDUCTIVE LOGIC
• Frog 1 died at time t 1 .
• Frog 2 died at time t 2 .
• Frog 3 died at time t 3 .
• n. Frog n died at time t n.
•  All frogs are mortal.
• 7. PHIL 160
• 8. PHIL 160
• 9. PHIL 160
• 10. PHIL 160
• 11. PHIL 160
• 12. PHIL 160
• 13. PHIL 160 STRATEGY: • Identify phenomenon to explain (childbed fever). • Find similar settings, one with the phenomenon, the other without.
• 14. PHIL 160 STRATEGY: • Identify phenomenon to explain (childbed fever). • Find similar settings, one with the phenomenon, the other without. • Identify differences between settings. • Test to see which differences are relevant to the phenomenon.
• 15. PHIL 160 Find the difference between wards that explains higher rate of childbed fever in 1st division ward. Test: changing the difference lowers rate of childbed fever in 1st division ward. STRATEGY:
• 16. PHIL 160 Deductive Argument
• If “priest-terror” causes childbed fever, rerouting priest/removing bell will lower childbed fever rate.
• Rerouting priest/removing bell does not lower childbed fever rate.
•  “ Priest-terror” does not cause childbed fever.
• 17. PHIL 160
• If delivering on back causes childbed fever, switching to lateral deliveries will lower childbed fever rate.
• Switching to lateral deliveries does not lower childbed fever rate.
•  Delivering on back does not cause childbed fever.
Deductive Argument
• 18. PHIL 160 Inductive Argument
• Much higher rates of childbed fever in wards attended by physicians and medical students than in wards attended by midwives.
•  Childbed fever must be caused by something physicians and medical students (but not midwives) are exposed to.
• 19. PHIL 160 Inductive Argument
• Childbed fever caused by something physicians and medical students (but not midwives) are exposed to.
• Physicians and medical students (but not midwives) do autopsies.
• Kolletschka got childbed fever after an autopsy.
•  Childbed fever must be caused by something physicians and medical students (but not midwives) are exposed to in autopsies (“cadaveric matter”).
• 20. PHIL 160 Inductive Argument
• Physicians and medical students pick up cadaveric matter from autopsies.
• If hands and instruments are washed with chlorinated lime, removes or destroys cadaveric matter.
• When physicians and medical students wash with chlorinated lime, childbed fever rate in 1st division ward declines.
•  Cadaveric matter causes childbed fever.
• 21. PHIL 160 Big Assumptions • Cadaveric matter exists, transmitted from autopsies. • Chlorinated lime removes or destroys cadaveric matter. No one observed cadaveric matter!
• 22.
• Physicians and medical students pick up cadaveric matter from autopsies.
• If hands and instruments are washed with chlorinated lime, removes or destroys cadaveric matter.
• When physicians and medical students wash with chlorinated lime, childbed fever rate in 1st division ward declines.
•  Cadaveric matter causes childbed fever.
PHIL 160 Inductive Argument = premises support conclusion Change that affects outcome.
• 23. PHIL 160 Did Semmelweis prove his conclusion?
• If H is true, then so is I.
• (As the evidence shows) I is true.
•  H is true.
“ fallacy of affirming the consequent” True premises don’t guarantee a true conclusion. (There might be another reason I is true!)
• 24. PHIL 160
• If cadaveric matter causes childbed fever, then removing/destroying it by washing with chlorinated lime will reduce rate of childbed fever.
• (As the evidence shows) washing with chlorinated lime reduces rate of childbed fever.
•  Cadaveric matter causes childbed fever.
Did Semmelweis prove his conclusion? “ fallacy of affirming the consequent”
• 25. PHIL 160 Semmelweis used his observations to find the relevant difference. His theory led to an effective intervention. But, the data didn’t prove his conclusion.
• 26. PHIL 160 Where’s the deduction?
• If H is true, then so is I.
• (As the evidence shows) I is false.
•  H is false.
Ruling out potential causes.
• 27. PHIL 160
• If “priest-terror” causes childbed fever, rerouting priest/removing bell will lower childbed fever rate.
• Rerouting priest/removing bell does not lower childbed fever rate.
•  “ Priest-terror” does not cause childbed fever.
Where’s the deduction? Ruling out potential causes.
• 28. PHIL 160 What’s wrong with induction? Supporting potential causes of childbed fever.
• If H is true, then so is I.
• (As the evidence shows) I is true.
•  H is true.
“ fallacy of affirming the consequent” Where’s the induction?
• 29. PHIL 160
• 30. PHIL 160 All knowledge through experience. Empiricism: (Anything I know has backing in empirical data.)
• 31. PHIL 160
• 32. PHIL 160
• 33. PHIL 160
• 34. PHIL 160
• 35. PHIL 160 Can’t get empirical data about things you haven’t observed! Problem of induction: Can’t be certain things you haven’t observed will be like things you have observed!