popper-logic-scientific-discovery

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some structural components of a theory of experience
anything stop him searching for laws, including laws of this kind. And
however successfully we might operate with probability estimates, we
must not conclude that the search for precision laws is vain.
These reflections are not by any means the outcome of the imaginary
experiment described in section 77; quite the contrary. Let us assume
that the uncertainty relations are not refuted by this experiment (for
whatever reason—say, because the experimentum crucis described in
appendix vi would decide against the quantum theory): even then
they could only be tested as frequency statements and could only be
corroborated as frequency statements. Thus in no case should we be
entitled to draw indeterministic conclusions from the fact that they are
well corroborated.* 2
Is the world ruled by strict laws or not? This question I regard as
metaphysical. The laws we find are always hypotheses; which means
that they may always be superseded, and that they may possibly be
deduced from probability estimates. Yet denying causality would be the
same as attempting to persuade the theorist to give up his search; and
that such an attempt cannot be backed by anything like a proof has just
been shown. The so-called ‘causal principle’ or ‘causal law’, however it
may be formulated, is very different in character from a natural law;
and I cannot agree with Schlick when he says, ‘ . . . the causal law can
be tested as to its truth, in precisely the same sense as any other natural
law’. 1
* 2 I still believe that this analysis is essentially correct: we cannot conclude from the
success of frequency predictions about penny tosses that the single penny tosses are
undetermined. But we may argue in favour of, say, an inderministic metaphysical view by
pointing out difficulties and contradictions which this view might be able to dissolve.
1 Schlick, Die Kausalität in der gegenwärtigen Physik, Die Naturwissenschaften 19, 1931, p. 155,
writes as follows: (I quote the passage in full; cf. also my notes 7 and 8 to Section 4) ‘Our
attempts to find a testable statement equivalent to the principle of causality have failed;
our attempts to formulate one have only led to pseudo-statements. This result, however,
does not after all come as a surprise, for we have already remarked that the truth of the
causal law can be tested in the same sense as that of any other natural law; but we have also
indicated that these natural laws in their turn, when strictly analysed, do not seem to have
the character of statements that are true or false, but turn out to be nothing but rules for
the (trans-) formation of such statements.’ Schlick had already earlier held that the causal
principle should be placed on a par with natural laws. But as at that time he regarded
natural laws as genuine statements he also regarded ‘the causal principle . . . as an
empirically testable hypothesis’. Cf. Allgemeine Erkenntnislehre, 2nd edition, 1925, p. 374.