Abstract

According to Karl von Frisch's method of reasoning, the conjunction of two generalizations must have the same grade of support as has the less well supported of the two or as both have if they are equally well supported. Also, any substitution-instance of a generalization must have the same grade of support as the generalization, since it is equally resistant to falsification by manipulations of relevant variables. So substitution-instances conform to the same conjunction principle as generalizations. The assumption of evidential replicability is crucial here and bars Carnap's confirmation-measures, or any form of enumerative induction, from applying to experimental reasoning like von Frisch's. Once the correct negation principle for inductive support has been established, it becomes clear how the emergence of mutually contradictory support-assessments can function as a _reductio ad absurdum_ argument for the revision of a list of relevant variables. A support-function for generalizations of a certain category applies not only to those propositions that are constructed out of the basic vocabulary of the category but also to those that have been constructed out of this category when it has been enriched by the addition of terms describing the variants of relevant variables.