In the Tractatus Logico-Philosophicus, Wittgenstein more or less lays out a position that any statement which does not directly link to an empirical observation is "nonsense". Of course, it wasn't hard to realize that most, or perhaps all, of the very book he had written would then have to be counted as nonsense. He got around this probably thus:

My propositions serve as elucidations in the following way: anyone who understands me eventually recognizes them as nonsensical, when he has used them - as steps - to climb beyond them. (He must, so to speak, throw away the ladder after he has climbed up it.) He must transcend these propositions, and then he will see the world aright.

So in other words, no one is allowed to give nonsensical statements, starting the exact moment after they read Wittgenstein. A rather strange solution, to be sure, but what can you do I guess?