Overcoming Bias has a good article about scientists holding unscientific beliefs outside the lab. The gist of it is, if a scientist throws out science when he leaves work, does he really understand what it’s for and how it works?
Why? Well, suppose that an apprentice shepherd is laboriously trained to count sheep, as they pass in and out of a fold. Thus the shepherd knows when all the sheep have left, and when all the sheep have returned. Then you give the shepherd a few apples, and say: “How many apples?” But the shepherd stares at you blankly, because they weren’t trained to count apples – just sheep. You would probably suspect that the shepherd didn’t understand counting very well.