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

1. Unit 2The logic of scientific discovery

2. Demarcation

3. Science and knowledge? What is the difference between science and pseudo-science? Scientists claim to increase our knowledge of the world But don’t astronomers and protagonists of intelligent design claim the same?

4. demarcation What kind of theory, what kind of methodology, is useful and will advance humankind. This is called the demarcation problem.

5. Back to epistemology Two main ideas about how to increase knowledge: empiricism and rationalism. Two related modern positions: logical positivism critical rationalism

6. Logical Positivism

7. Positivism positivism was developed by the 19th century philosopher and sociologist August Comte. Positivism is an epistemological perspective that holds that sense experience and positive verification are the only ways to get to authentic knowledge.

8. Vienna circle and logical positivism

9. Ludwig Wittgenstein (1889-1951)TractatusLogico-Philosophicus

11. Whereof one cannot speak, thereof one must be silent.

13. Analytic-synthetic (again) Synthetic: All men are arrogant Analytic: All men are human Analytic sentences and claims are empty, they are tautological Therefore only synthetic claims (induction) are scientific

15. reductionism Every meaningful statement can be reduced to protocol sentences Protocol sentence: a sentence that describes immediate experience

16. Confirmation and structure According to the verifiability principle a proposition is only "cognitively meaningful" if there is a procedure to determine whether it is true or false. The logical positivist tried to find logical patterns in experience, unobservable structures, laws, like the law of gravity.

17. Logical positivism in short The analytic-synthetic distinction The verifiability theory of meaning

19. The problem of induction

20. We can verify (confirm) anything with everything Hypothesis (h): All ravens (F’s) are black (G) Every f we see that is g confirms h All F’s are G is logically equivalent to all nonblack things are not ravens. Following this logic: the observation of a white shoe also confirms the hypothesis

21. Sir Karl Popper (1902-1994) critical rationalism

22. Theory-ladenness of data A theory is like a flashlight Everything you shine on you see in the light of the flashlight. So confirmation as demarcation criterion won’t work.

23. Einstein versus Marx Popper wanted to distinguish between real and pseudoscience Real science: Newton and Einstein Pseudoscience: Marx and Darwin

24. Poppers demarcation criterion A theory is scientific if it is logically consistent. A theory is scientific if it is falsifiable.

25. Falsification

26. Falsification A theory is like a rule When falsified the rule is rejected (There are no ad hoc adjustments) Some statements are only falsifiable in theory, while others are even falsifiable in practice. The more risky a theory, the better the theory

27. Marxism Marx called his ideas science Popper called the ideas of Marx pseudoscience Because uses ad hoc hypotheses

28. Example One notices a white swan. From this one can conclude: At least one swan is white. From this, one may wish to conjecture: All swans are white. If we observe a black swan the theory is falsified.

29. Problem solved? The big six: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur Mono Lake: substitute phosphorus with arsenic