The Emperor's New Clothes story has always bothered me. After the little boy says, but he doesn't have any clothes on, why doesn't everyone else just laugh and say, oh, look, the little boy is not sophisticated and clever enough to see the fine new clothes of the emperor, as I can? Wasn't that the con, that only the best quality people could see the clothes? So why should one person's announcement make it common knowledge that there were no clothes? The story doesn't quite work for me.
However, there certainly are situations where an unacknowledged fact is known by everyone, and then someone foolishly or clumsily announces it, making it common knowledge. This leads to a feeling of mutual embarrassment, but sometimes the result is merely an awkward silence, a pause, and then the remark is ignored and things go on as before. This kind of situation suggests that making certain facts common knowledge is only a partial step towards social catastrophe, and depending on the situation it may be possible to rescue things by pretending it didn't happen.
It's possible that such "rescueable" situations are precisely the ones where the uncomfortable fact was already common knowledge, hence announcing it doesn't fundamentally change things, and the only question is whether to respond to the announcement and thereby make the fact even more prominent. Then it might be that in situations where the fact was known but was not common knowledge, where some people suspect that others don't know, or at least that certain people don't know that other people know, the announcement would produce a sudden transition to the common-knowledge state. Then this would transform the social dynamics so dramatically that it would not be possible to pretend it hadn't happened.
The Emperor's New Clothes story has always bothered me. After the little boy says, but he doesn't have any clothes on, why doesn't everyone else just laugh and say, oh, look, the little boy is not sophisticated and clever enough to see the fine new clothes of the emperor, as I can? Wasn't that the con, that only the best quality people could see the clothes? So why should one person's announcement make it common knowledge that there were no clothes? The story doesn't quite work for me.
Since everyone was pretending they could see the clothes, no-one cons...
Followup to: Belief in Belief
One of those insights that made me sit upright and say "Aha!" From The Uncredible Hallq:
The power of real deception - outright lies - is easy for even us nerds to understand.
The notion of a lie that the other person knows is a lie, seems very odd at first. Up until I read the Hallq's explanation of Pinker, I had thought in terms of people suppressing uncomfortable thoughts: "If it isn't said out loud, I don't have to deal with it."
Like the friends of a terminal patient, whose disease has progressed to a stage that - if you look it up online - turns out to be nearly universally fatal. So the friends gather around, and wish the patient best hopes for their medical treatment. No one says, "Well, we all know you're going to die; and now it's too late for you to get life insurance and sign up for cryonics. I hope it isn't too painful; let me know if you want me to smuggle you a heroin overdose."
So even that is possible for a nerd to understand - in terms of, as Vassar puts it, thinking of non-nerds as defective nerds...
But the notion of a lie that the other person knows is a lie, but they aren't sure that you know they know it's a lie, and so the social situation occupies a different state from common knowledge...
I think that's the closest I've ever seen life get to imitating a Raymond Smullyan logic puzzle.
Added: Richard quotes Nagel on a further purpose of mutual hypocrisy: preventing an issue from rising to the level where it must be publicly acknowledged and dealt with, because common ground on that issue is not easily available.