One question which Wittgenstein concerned himself with is the rules of language. He postulated a language which consisted of two speakers, one of whom was a mason and the other of whom was a mason's assistant. The language had two words - "brick" and "mortar". Each time the mason uttered "brick" it meant that the assistant would hand him a brick and each time he said "mortar" the assistant would provide him with mortar. Wittgenstein postulated that even in so impoverished a system humor would be possible - the one type of joke in this language would be if the mason said "mortar" and the assistant handed him a "brick" instead.
But it's only funny if the mason thinks its funny, and perhaps also only if the assistant meant it to be funny. Otherwise, it's a mistake. Or it was a protest on the part of the assistant. Or several other alternate possibilities I can think of.
And again, what's "funny" between these two masons may not be "funny" between the next pair. So "humor" has some characteristics that are independent of this primitive two-word language.
The point being that "humor" in that simple system presumes the existence of non-concrete information over and above the simple passing of brick and mortar, so that they can tell the difference between humor and something else. It requires the existence of meaning beyond brick-and-mortar interaction.