popper-logic-scientific-discovery

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new appendices
be the source from which the theories of the empirical sciences
spring).
Varying and generalizing a well-known remark of Einstein’s, 4 one
might therefore characterize the empirical sciences as follows: In so far as
a scientific statement speaks about reality, it must be falsifiable: and in so far as it is not
falsifiable, it does not speak about reality.
A logical analysis would show that the rôle of (one-sided) falsifiability
as a criterion for empirical science is formally analogous to that of noncontradictoriness
for science in general. A contradictory system fails to single
out, from the set of all possible statements, a proper sub-set; similarly, a
non-falsifiable system fails to single out, from the set of all possible
‘empirical’ statements (of all singular synthetic statements), a proper
sub-set. 5
2
The second note consists of some remarks which I made in a discussion
of a paper read by Reichenbach at a philosophical conference in
Prague, in the summer of 1934 (when my book was in page proofs). A
report on the conference was later published in Erkenntnis, and my contribution,
here published in translation, was printed in Erkenntnis 5,
1935, p. 170 ff.
On the so-called ‘Logic of Induction’ and the
‘Probability of Hypotheses’
I do not think that it is possible to produce a satisfactory theory of what
is traditionally—and also by Reichenbach, for example—called ‘induction’.
On the contrary, I believe that any such theory—whether it uses
classical logic or a probability logic—must for purely logical reasons
4 Einstein, Geometrie und Erfahrung, 1921, pp. 3f. *Added 1957: Einstein said: ‘In so far as the
statements of mathematics speak about reality, they are not certain, and in so far as they
are certain, they do not speak about reality.’
5 A fuller exposition will be published soon in book form (in: Schriften zur wissenschaftlichen
Weltauffassung, ed. by Frank and Schlick, and published by Springer in Vienna). *Added
1957: The reference was to my book, Logik der Forschung, then in process of being printed.
(It was published in 1934, but—in accordance with a continental custom—with the
imprint ‘1935’; and I myself have, therefore, often quoted it with this imprint.)