I know facts about Zimbardo's prison experiment because I studied it in University. I know the feeling a nail makes when I hit it with a hammer because I have done it. I know Greece has been granted a second bailout because I overheard someone talking about reading it in the news.

These are things that I know why I know them. I guess that you would be able to give me reasons why you think the world is round.

It is harder when there are many small pieces of evidence. I hadn't thought of that. And I agree that my reccomendations are not possible to do all the time.

I would be happy to revise them to only apply when receiving facts you find surprising or you expect the other person to be surprised. That way we only need two, well defined stop signs in our system 1 thinking. Stop sign one is when we hear "I believe ..." find which category it fits into. Sign two is when we are surprised by a fact reply with " fascinating, where did you hear that".