popper-logic-scientific-discovery

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new appendices
statements’;* 1 that is to say, that they are a particular kind of ‘pseudostatement’.
This attempt to solve the problem (the solution seems to me to be
verbal anyway) shares with all the older attempts, such as apriorism,
conventionalism, etc. a certain unfounded assumption; it is the assumption
that all genuine statements must be, in principle, completely
decidable, i.e. verifiable and falsifiable; more precisely, that for all genuine
statements, an (ultimate) empirical verification, and an (ultimate)
empirical falsification must both be logically possible.
If this assumption is dropped, then it becomes possible to resolve in
a simple way the contradiction which constitutes the problem of
induction. We can, quite consistently, interpret natural laws or theories
as genuine statements which are partially decidable, i.e. which are, for
logical reasons, not verifiable but, in an asymmetrical way, falsifiable only: they
are statements which are tested by being submitted to systematic
attempts to falsify them.
The solution suggested here has the advantage of preparing the way
also for a solution of the second and more fundamental of two problems
of the theory of knowledge (or of the theory of the empirical
method); I have in mind the following:
(2) Main Problem. This, the problem of demarcation (Kant’s problem of the
limits of scientific knowledge) may be defined as the problem of finding
a criterion by which we can distinguish between assertions (statements,
systems of statements) which belong to the empirical sciences,
and assertions which may be described as ‘metaphysical’.
According to a solution proposed by Wittgenstein, 2 this demarcation
is to be achieved with the help of the idea of ‘meaning’ or ‘sense’:
every meaningful or senseful proposition must be a truth function of
‘atomic’ propositions, i.e., it must be logically completely reducible to
(or deducible from) singular observation statements. If some alleged
* 1 In order to get Schlick’s intended meaning, it might be better to say ‘rules for the
formation or transformation of statements’. The German reads: ‘Anweisungen zur Bildung von
Aussagen’. Here ‘Anweisungen’ may be translated, clearly, by ‘rules’; but ‘Bildung’ had, at that
time, hardly yet any of the technical connotations which have since led to the clear
differentiation between the ‘formation’ and the ‘transformation’ of statements.
2 Wittgenstein, Tractatus Logico-Philosophicus (1922).