Something really stupid and anoying they make you learn in Communication Studies graduate programs even though you're a rhetorician and couldn't really give a rat's ass.
Logical positivism asserts that only statements about empirical observations are meaningful, effectively asserting that all metaphysical statements are meaningless. Unfortunately, this fundamental tenet of logical positivism belongs to the family of statements that it asserts to be meaningless. As a result, the entire edifice of logical positivism vanishes in a puff of logic. This insight appears not to have occurred to the logical positivist school of philosophers.