Is there really an answer?

[Iamblue]

A question was asked at work the other day, and I cannot see how there can be a difinitive answer (but I am a bit thick). Can anyone help?

4 men are buried up to their necks in sand. Man A is to the left of a brick wall, men B C and D are to the right. They are all facing left. Each has a hat on his head. There are 2 white hats and 2 black hats. They cannot see their own hat. The only way they can escape is if any one of the men can correctly name the colour of the hat on his own head. As soon as any one of the men submits an answer, the game is over. How do they escape? There is no hole in the wall, no mirrors etc. It is not a trick question and it is driving me mad.

I am (almost) sure it cannot be done, but any answer would be great. Perhaps someone has seen the question before?

Thanks.

[crofter]

If D remains silent, then C calls the colour opposite to B's hat!

[BigMac]

Ah, the memories! This was almost my first question on AB.

[Iamblue]

Crofter, you are an absolute star. Thanks. I would have given you more than 3 stars if I could.