Does the cat know that? My friend, just for sharing, for fun. It's not my original. Knowledge about facts versus knowledge about knowledge. This is an old joke about a man who believed he was a mouse: After some years in the mental asylum, one day he finally managed to convince himself that he was not a mouse. On the day of his release, the director bids farewell, and the man walks towards the gate. Less than five minutes later, he is back, trembling. "What's wrong, Sir?", the director asks. “There is a c-c-cat w-w-waiting on the street." "But you know that you are not a mouse, Sir, right?" "Well, yes, sure I know. But how do I know the cat knows?"