1. FALSIFIABILITY IS THE HEART OF SCIENCE
KARL POPPER
FALSIFIABILITY
IS THE HEART OF SCIENCE

2. Sir KARL POPPER 1902-1994 Hume is right: we never get beyond
conjectures.
“Darwinian” view
of human
“knowledge”:
PS1TT1
EE1PS2…

3. 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.

4. NON-SCIENCE IS UNFALSIFIABLE.
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.

5. 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.

6. 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

7. 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

8. 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.]

9. 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

10. 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

11. 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?

12. 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,…