Unit 2. The logic of scientific discovery


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Unit 2. The logic of scientific discovery [Philosophy of Science]

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Unit 2. The logic of scientific discovery

  1. 1. Unit 2The logic of scientific discovery <br />
  2. 2. Demarcation<br />
  3. 3. Science and knowledge?<br />What is the difference between science and pseudo-science? <br />Scientists claim to increase our knowledge of the world<br />But don’t astronomers and protagonists of intelligent design claim the same?<br />
  4. 4. demarcation<br />What kind of theory, what kind of methodology, is useful and will advance humankind. <br />This is called the demarcation problem.<br />
  5. 5. Back to epistemology<br />Two main ideas about how to increase knowledge: empiricism and rationalism. <br />Two related modern positions: <br />logical positivism <br />critical rationalism<br />
  6. 6. Logical Positivism<br />
  7. 7. Positivism<br />positivism was developed by the 19th century philosopher and sociologist August Comte. <br />Positivism is an epistemological perspective that holds that sense experience and positive verification are the only ways to get to authentic knowledge. <br />
  8. 8. Vienna circle and logical positivism<br />
  9. 9. Ludwig Wittgenstein (1889-1951)TractatusLogico-Philosophicus<br />
  10. 10.
  11. 11. Whereof one cannot speak, thereof one must be silent.<br />
  12. 12.
  13. 13. Analytic-synthetic (again)<br />Synthetic: All men are arrogant<br />Analytic: All men are human<br />Analytic sentences and claims are empty, they are tautological<br />Therefore only synthetic claims (induction) are scientific<br />
  14. 14.
  15. 15. reductionism<br />Every meaningful statement can be reduced to protocol sentences<br />Protocol sentence: a sentence that describes immediate experience<br />
  16. 16. Confirmation and structure<br />According to the verifiability principle a proposition is only "cognitively meaningful" if there is a procedure to determine whether it is true or false. <br />The logical positivist tried to find logical patterns in experience, unobservable structures, laws, like the law of gravity. <br />
  17. 17. Logical positivism in short<br />The analytic-synthetic distinction<br />The verifiability theory of meaning<br />
  18. 18.
  19. 19. The problem of induction<br />
  20. 20. We can verify (confirm) anything with everything<br />Hypothesis (h): All ravens (F’s) are black (G)<br />Every f we see that is g confirms h<br />All F’s are G is logically equivalent to all nonblack things are not ravens. <br />Following this logic: the observation of a white shoe also confirms the hypothesis<br />
  21. 21. Sir Karl Popper (1902-1994)<br /> critical rationalism<br />
  22. 22. Theory-ladenness of data<br />A theory is like a flashlight<br />Everything you shine on you see in the light of the flashlight.<br />So confirmation as demarcation criterion won’t work.<br />
  23. 23. Einstein versus Marx<br />Popper wanted to distinguish between real and pseudoscience<br />Real science: Newton and Einstein<br />Pseudoscience: Marx and Darwin<br />
  24. 24. Poppers demarcation criterion<br />A theory is scientific if it is logically consistent.<br />A theory is scientific if it is falsifiable.<br />
  25. 25. Falsification<br />
  26. 26. Falsification<br />A theory is like a rule<br />When falsified the rule is rejected (There are no ad hoc adjustments)<br />Some statements are only falsifiable in theory, while others are even falsifiable in practice.<br />The more risky a theory, the better the theory<br />
  27. 27. Marxism<br />Marx called his ideas science<br />Popper called the ideas of Marx pseudoscience<br />Because uses ad hoc hypotheses<br />
  28. 28. Example<br />One notices a white swan. From this one can conclude:<br />At least one swan is white.<br />From this, one may wish to conjecture:<br />All swans are white.<br />If we observe a black swan <br />the theory is falsified.<br />
  29. 29. Problem solved?<br />The big six:<br />carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur<br />Mono Lake: substitute phosphorus with arsenic<br />