Lecture 10: the revenge of the rationalists Flashcards
logical positivism fails because… (4 redenen)
– theoretical concepts are richer than summaries to observations & observations are not neutral: theory-ladenness
– Underdetermination of theory by observation
– the induction problem blocks verification of scientific statements
– Science is full of unobservable entities (which are supposed to be unverifiable)
- Popper worked in a daycare center with
Alfred Adler - Popper presented Adler with a case that
he felt didn’t fit into Adler’s theory. - Adler explained the case by modifying his
theory, showing great certainty - “Slightly shocked, I asked him how he
could be so sure. ‘Because of my
thousandfold experience’, he replied;
whereupon I could not help saying: ‘And
with this new case, I suppose, your
experience has become thousand-and-
one-fold.’” (Popper, 1978)
oke
“I found that those of my friends who were
admirers of Marx, Freud, and Adler, were
impressed by a number of points common to
these theories, and especially by their
apparent explanatory power…Once your eyes
were thus opened you saw confirming
instances everywhere: the world was full
of verifications of the theory. ” (Popper, 1978)
oke
wat vond popper dus over adler, freud en marx
- These theories can explain all facts
- This might sound as something
wonderful… - Popper, however, realizes: This is not a
strength, but a weakness!
wat gebeurde er net in de tijd dat popper actief was
- In the same period Einstein posits the theory of relativity
- This theory predicts that light deflects along a planet
- The solar eclipse of 1919 enables Arthur Eddington to test the prediction
- If the prediction didn’t come true, this would proof Einstein’s theory wrong
wat deed popper met dit ding van einstein
- So Einstein’s theory excludes certain events
- This is a strong theory exactly because it can not explain everything
- Karl Popper recognizes that this marks the essence of science
- After all, if you’re wrong, you can find out!
- With a theory that can explain everything this is impossible
- Such a theory is uninformative
induction en deduction verschil
induction: observation -> theory
deduction: theory -> observation
wat zei popper over induction
induction is onmogelijk, maar ook niet noodzakelijk: instead we can do deduction (use theories to derive predictions about observations)
- Theories are bold conjectures whose predictions can be tested against observations
- Popper: theory-free observation is impossible, but is also not needed
- Induction is impossible: you cannot induce theories from observations
- But that is ok, because instead we can do deduction: theories can be used to derive predictions about observations!
oke
hoe vond popper dat je van theorie naar observatie moest gaan
theories are not constructed from observations (wat de logical positivists zeiden), but they emerge from a creative act. and then predictions are derived from this, which are tested on the basis of observation.
dus wat was het grootste verschil tussen logical positivists en popper
logical positivists: empiricists, induction, observations -> theories
popper: rationalist, deduction, theory -> predictions (which are tested via observation)
waarom denkt popper dat hij het induction problem heeft opgelost
because it doesnt really matter how the theory arises, the only scientific act is refutation. this can be done by deducing predictions from the theory that can then be tested. and deduction is logically valid!
hypothetico-deductive model=
- start with theory
- deduce predictions from theory
- test these predictions
- if these predictions dont come true: falsify
- if they do come true: corroboration
corroborated theory =
(not the same as verification!!!)
a corroborated theory is one that is strong because it survived a risky test, but it is not accepted.
even kijken naar blaadjes
oke
empirical cycle
observation - theory construction - prediction - test - evaluate - observation…
door adriaan de groot
wat vond popper over theory development
helemaal vrij, moet gewoon creatief gebeuren.
popper vouched for hypothesis testing, werkte dus niet zo goed bij psychologie en filosofie (nu veel kritiek). popper is very normative (this is how you should do science), kuhn en lakatos meer descriptive (this is how science happens).
oke
popper tijdens…
ww2
waardoor werd popper eigenlijk aangezet
door een foutje in adler zijn theory
wat deed adler
explained all behaviour via inferiority complexes
wat is een verschil tussen theorieen maken en testen
– context of discovery (there is no logic for theory development)
– context of justification (strict rules for the logic of testing: modus tollens)
dus theorie bedenken is heel vrij, theorie testen is heel strict.
waarom is popper een rationalist
theories spring from the imagination, en daarna logisch over nadenken (part of the content of our theories comes from ratio, not from observation)
wat is een verschil tussen popper en bijvoorbeeld plato
- popper considers the ratio fallible
- his version of rationalism is called critical rationalism (nog steeds populair)
demarcation=
demarcation criterion distinguishes science from pseudoscience
wat was popper zijn demarcation criterion
falsification
falsification criterion=
statements or theories are scientific when they are in conflict with possible observations