Back in the 70s I read an extraordinary novel called 'The Erl King'. I think it was by a French writer called something like Michel de Tournier (possibly?). It's a long time since I read it but, as far as I can recall, it was about a rather unworldly man who builds a sort of vast symbolic system for explaining the world around him and then finds that the inverse of his system has a ghastly counterpart in the real world.

Oh dear, I've probably put you off reading it now ...