Wovon man nicht sprechen kann, darüber muss man schweigen.


Translated: Whereof one cannot speak, thereof one must be silent.

or more colloquially, "What you can't talk (knowledgeably) about, you have to shut up about."

Ludwig Wittgenstein


This bit of positivist philosophy is very popular in academe now. The only problem is that much of life then remains in the realm that can't be spoken of. This leaves broad areas in the domain of people who call up open line talk shows, who can speak with complete authority on any subject whatsoever.