Abstract

In order to confirm any statement of the form A are B we consider a sufficiently large number of A in order to check them for having or failing to have property B. But logic leads us to believe that A are B is equivalent to non-B are non-A. If this is so then it seems reasonable to suppose that we confirm and in the same way. Whatever set of things we consider for confirming one must be the same set that we consider for the other. Yet in confirming the set considered seems to be the set of A, while in confirming the set considered seems to be the set of non-B. How can two logically equivalent statements be confirmable in different ways?