Undercover Economist

I promised a hint for yesterday’s logic puzzle. It is, after all, the hardest logic puzzle ever posed…
Here’s a hint, then. And it’s a big one. For any yes/no question, Q, you can ask any guardian this question:

“If I asked you Q in your current mental state, would you say ‘ja’?”

And you’ll get the answer “ja” if and only if the truthful answer to Q is yes. This is true whether you ask the question of Knight, Knave or Chaos.