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206<br />

some structural components of a theory of experience<br />

nature is actually constituted (or not constituted) according to these<br />

laws.* 4<br />

72 THE THEORY OF RANGE<br />

In section 34 I said that a statement which is falsifiable to a higher<br />

degree than another statement can be described as the one which is<br />

<strong>logic</strong>ally more improbable; and the less falsifiable statement as the one<br />

which is <strong>logic</strong>ally more probable. The <strong>logic</strong>ally less probable statement<br />

entails 1 the <strong>logic</strong>ally more probable one. Between this concept of <strong>logic</strong>al<br />

probability and that of objective or formally singular numerical probability<br />

there are affinities. Some of the philosophers of probability (Bolzano,<br />

von Kries, Waismann) have tried to base the calculus of probability<br />

upon the concept of <strong>logic</strong>al range, and thus upon a concept which (cf.<br />

section 37) coincides with that of <strong>logic</strong>al probability; and in doing so,<br />

they also tried to work out the affinities between <strong>logic</strong>al and numerical<br />

probability.<br />

Waismann 2 has proposed to measure the degree of interrelatedness<br />

between the <strong>logic</strong>al ranges of various statements (their ratios, as it<br />

were) by means of the relative frequencies corresponding to them, and<br />

thus to treat the frequencies as determining a system of measurement for<br />

ranges. I think it is feasible to erect a theory of probability on this<br />

foundation. Indeed we may say that this plan amounts to the same<br />

thing as correlating relative frequencies with certain ‘indefinite predictions’<br />

—as we did in the foregoing section, when defining formally<br />

singular probability statements.<br />

It must be said, however, that this method of defining probability is<br />

only practicable when a frequency theory has already been constructed.<br />

Otherwise one would have to ask how the frequencies used in defining<br />

the system of measurement were defined in their turn. If, however, a<br />

frequency theory is at our disposal already, then the introduction of the<br />

theory of range becomes really superfluous. But in spite of this objec-<br />

* 4 This somewhat disparaging characterization fits perfectly my own views which I now<br />

submit to discussion in the ‘Metaphysical Epilogue’ of my Postscript, under the name of<br />

‘the propensity interpretation of probability’.<br />

1 Usually (cf. section 35).<br />

2 Waismann, Logische Analyse des Wahrscheinlichkeitsbegriffes, Erkenntnis 1, 1930, p. 128 f.

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