The moon is made of green cheese!

I stumbled on a rather belated obituary for the mathematician Martin Löb today. He died in August at the age of 85. He taught at Universities in Britain and the Netherlands and is probably best known for the Löb theorem. It is sort of a mutant offspring of Gödel's Incompleteness Theorem of 1931, dealt with self-referential statements which asserted that they were not provable but true. Löb's theorem deals with statements that are provable but false, again relying on self-reference. His most famous, non-mathematical statement relevant to his theorem is:

if this sentence is true then the moon is made of green cheese.

Hmmm. I don't remember tasting blue cheese in Moon Pies!