In the logic of science here outlined it is possible to avoid using the concepts ‘true’ and ‘false’. …
Whilst we assume that the properties of physical objects (of ‘genidentical’ objects in Lewin’s sense) change with the passage of time, we decide to use these logical predicates in such a way that the logical properties of statements become timeless: if a statement is a tautology, then it is a tautology once and for all. This same timelessness we also attach to the concepts ‘true’ and ‘false’, in agreement with common usage. It is not common usage to say of a statement that it was perfectly true yesterday but has become false today. If yesterday we appraised a statement as true which today we appraise as false, then we implicitly assert today that ; that the statement was false even yesterday—timelessly false—but that we erroneously ‘took it for true’.
Here one can see very clearly the difference between truth and corroboration. The appraisal of a statement as corroborated or as not corroborated is also a logical appraisal and therefore also timeless; for it asserts that a certain logical relation holds between a theoretical system and some system of accepted basic statements. But we can never simply say of a statement that it is as such, or in itself, ‘corroborated’ (in the way in which we may say that it is ‘true’). We can only say that it is corroborated with respect to some system of basic statements—a system accepted up to a particular point in time. ‘The corroboration which a theory has received up to yesterday’ is logically not identical with ‘the corroboration which a theory has received up to today’. Thus we must attach a subscript, as it were, to every appraisal of corroboration—a subscript characterizing the system of basic statements to which the corroboration relates (for example, by the date of its acceptance).
Corroboration is therefore not a ‘truth value’; that is, it cannot be placed on a par with the concepts ‘true’ and ‘false’ (which are free from temporal subscripts); for to one and the same statement there may be any number of different corroboration values, of which indeed all can be ‘correct’ or ‘true’ at the same time. For they are values which are logically derivable from the theory and the various sets of basic statements accepted at various times.
The above remarks may also help to elucidate the contrast between my views and those of the pragmatists who propose to define ‘truth’ in terms of the success of a theory—and thus of its usefulness, or of its confirmation or of its corroboration. If their intention is merely to assert that a logical appraisal of the success of a theory can be no more than an appraisal of its corroboration, I can agree. But I think that it would be far from ‘useful’ to identify the concept of corroboration with that of truth.* [273-5]
* Thus if we were to define ‘true’ as ‘useful’ (as suggested by some pragmatists), or else as ‘successful’ or ‘confirmed’ or ‘corroborated’, we should only have to introduce a new ‘absolute’ and ‘timeless’ concept to play the role of ‘truth’.