 In order to be able to apply these notions in a useful way, we have to explain how to count the variants of a proposition, since for each variant of a proposition (as for each proposition in general) there are infinitely many others that are logically equivalent to it (e.g., due to replacing a part \([b]\) of the proposition by [non-non-\(b]\), [non-non-non-non-\(b]\) etc.). If we would count all of them, the resulting fractional number would not be very informative. Bolzano was completely aware of this problem (WL II, 79 f.), and he was very creative in developing methods for solving it as well as many other puzzling problems.