The parent argument proves too much, I think. Try adding the following, for example:

Since any communication can be described as the transmission of information, and, in order to be transmitted, this information must exist, any formal system of semiotics (providing it exists) can be encompassed by a larger formal system of physics. Taken together with the earlier observation (about the triviality of semiotics) we conclude that any formal explanation of physics must be trivial and/or incomplete.

I think the moral of the story is that one should not attempt to invoke Gödels Incompleteness Theorem in Social Science.