Karl popper falsifiability is the heart of science sir karl popper 1902-1994

KARL POPPER

• FALSIFIABILITY
• IS THE HEART OF SCIENCE

Sir KARL POPPER 1902-1994

• Hume is right: we
• never get beyond
• conjectures.
• “Darwinian” view
• of human
• “knowledge”:
• PS1TT1
• EE1PS2…

PROBLEM OF THE CRITERION (264, theme of whole essay)

• Problem: what distinguishes science from non-science or pseudo-science?
• Lots of theories in political “science” (e.g., Marx, Spengler, Nazism), psychoanalysis (Freud, Adler, Jung), claim to be scientific.
• ARE THEY?
• Popper’s experience in Adler’s clinic (p. 265).
• Everything is consistent with, hence
• corroborates or confirms his theory.

NONSCIENTIFIC THEORY

• Marx, Spengler, Hitler, Freud, Adler:
• Everything confirms their theories, nothing falsifies them.
• N.B.: not just every actual thing, but every conceivable thing.
• NON-SCIENCE IS UNFALSIFIABLE.

SCIENTIFIC THEORY

• Newton, Einstein: most conceivable things falsify their theories:
• N.B.: though no actual thing does
• Example: A body has to fall (orbit, etc.) with a precise acceleration (velocity, etc), or else theory is false.
• N.B.: though in fact theory is not
• falsified.

PROBLEM OF THE CRITERION

• Observation: Marx’s, Freud’s, Adler’s, etc., theories take no risk, but Einstein’s is risky (= falsifiable).
• So, maybe:
• Falsifiability is the criterion of science

FALSIFIABILITY 1 (P’s summary of numbered list, p. 266)

• Popper accepts above solution:
• Falsifiability is the criterion of science
• Falsifiability =DEF the logical possibility of being proven false by observation =DEF can conceive of such proof without self-contradiction

FALSIFIABILITY 2

• Falsification of scientific claim is logically valid:
• T  O
• ~ O_____
• Thus ~ T
• T=Theory is true
• O=Observation implied by theory occurs.
• [Recall Salmon, invalidity of scientific confirmation: T  O; O; Thus T.]

FALSIFIABILITY [3]

• Falsifiable or not?
• a) Unicorns do not exist.
• Assume: unicorns are not invisible
• b) Unicorns exist.
• c) 3 x 7 = 21
• d) Hitler never once wore mismatched socks.
• e) Dinosaurs once roamed the Earth

SCIENTIFIC THEORIES ARE PROHIBITIONS

• [explanation of Popper’s item #3, p. 266]
• In a state of perfect ignorance, all things are possible so far as we can tell.
• E.g., F=ma or F=2ma or F=3ma or…
• Knowledge rules out some possibilities
• OR: scientific theories are constrained
• by observational data

THE SCIENTIFIC ATTITUDE

• [explanation of Popper’s item #5, p. 266]
• “Genuine test” is defined in terms of attempts to falsify.
• Theories can be protected from the evidence by qualifications, promises, etc.
• E.g.: Is the theory of global warming
• falsified by the years of cooling?

POPPER’S “SOLUTION” OF HUME’S PROBLEM OF INDUCTION

• i) Deduction is the only logic; there is no inductive logic.
• ii) Theory of rationality: accept boldest unfalsified falsifiable theory
• bold=risky=high content
• Timid: the robin will fly south in the fall
• Bold: the robin will fly south on 26 Oct.
• Bolder: …26 Oct. at 1:23 p.m., SSW,…