Carnap v. Popper

Remember that Carnap thought that a sentence can only be a meaningful statement if we know the conditions for verifiability for that sentence.  In other words, a sentence is only meaningful if it can be verified.  Popper introduces an alternative standard for the statements of science.  As he notes that no verification can be permanent, he shifts attention from verifiabilility to falsifiability.  In Popper's terms, statements are only scientific if they can be falisified.  Any single statement from an existing system of scientific facts can be used to falsify an entire system.  A statement need not be falsified in order to be scientific.  But there must be the possibility that the statement can be falsified if it is a scientific statement.