DOES POPPER OFFER A RULE OF REJECTION?
With this I leave the question, ‘do we need a criterion of rejection?’ Let us assume now, without debate, that the absence of a rule is deplorable, and ask, ‘does Popper provide such a rule in a satisfactory manner?’
Popper’s chapter on basic statements (Chapter 5) is quite difficult to follow on this point.
The chapter contains admirable and understandable criticism of prevalent doctrines. But when I tried to expound and apply its doctrine of the empirical basis (in Chapter V above) I came in for a lot of criticism from Popper, some of his close associates and former students during the four years between acceptance and publication. Its argument was said by those familiar with Popper’s views to be hard to follow. Popper himself found it reprehensible. W. W. Bartley III, one of Popper’s most brilliant former students, convinced me that I may be able to clarify my argument against Popper — if I have one, which at the time he vehemently denied - by rereading Popper’s text more carefully and systematically. The present chapter follows this suggestion, and also a few of his more detailed ones. My own early reading of Popper on observation reports or basic statements was as follows. There is a rule which tells us when we are permitted to reject basic statements; otherwise we are not permitted to reject any. The rule is this. First, we should state or report as basic statement when we (sufficiently carefully?) observe - or think we observe - what the basic statement affirms. Secondly, we should try to test the basic statement, at the very least by repeating the observation it reports. Thirdly, if the basic statement is refuted (see below) it ought henceforth to be denied and the one refuting it be reported and affirmed in its stead. Fourthly, if the basic statement is not refuted it ought to stay affirmed. Fifthly, anyone who wishes to deny any hitherto affirmed basic statement may not do so except if he has succeeded in his attempts to refute it. One is always at liberty - is even encouraged - to test any basic statement one wishes, and as severely as one knows how.According to the rule just expounded, participants in the scientific enterprise are always bound to affirm all those basic statements which have stood up to test more recently. They are bound, to be sure, not by natural or psychological necessity, and not by the law of the land, but by rules freely adopted, we may remember, in order to escape dogmatism.
It is hard to say whether the previous two paragraphs paraphrase what is advocated in Chapter 5 of Popper’s Logic of Scientific Discovery. It once looked to me obvious that in that chapter, in Section 29, this rule was advocated. But Bartley has convinced me, at the very least, that no such rule is explicitly advocated there.
Let us suppose, then, that there is no rejection rule in that chapter.
It is then unsatisfactory, in that it condemns Neurath for failing to provide such a rejection rule while likewise failing to provide one. To be sure, Popper does suggest that after refutation a once-affirmed basic statement should be denied. This, of course, is a very important and far from trivial proposal, since in such cases we have the evidence of the senses for two propositions contradicting each other. But the question remains, ‘does Popper suggest that only when refuted ought a once- affirmed basic statement to be denied?’ If he does say that, then a rule which bars dogmatism (or which is meant to bar dogmatism) has been presented and I shall soon attempt to criticize it by showing that it is a rather dogmatic rule. If he does not say that, then he has not provided a rule which bars dogmatism, after having criticized Neurath for not having provided such a rule. (Here is a case where the reading of a text is highly context-dependent. Yet the text is too brief for a clear-cut decision.)
VI.