What probability should you assign as a Bayesian to the answer of a yes/no question being yes if you have absolutely no clue about what the answer should be?
If you truly have no clue, .5 yes and .5 no.
For example, let's say you are suddenly sent to the planet Progsta and a Sillpruk comes and asks you whether the game of Doldun will be won by the team Strigli.
Ah, but here you have some clues, which you should update on, and knowing how is much trickier. One clue is that the unkown game of Doldun could possibly have more than 2 teams competing, of which only 1 could win, and this should shift the probabilities in favor of "No". How much? Well that depends on your probability distribution for an unknown game to have n competing teams. Of course, there may be other clues that should shift the probabilty towards "yes".
But the game of Doldun could also have the possibility of cooperative wins. Or it could be unwinnable. Or Strigli might not be playing. Or Strigli might be the only team playing - it's the team against the environment! Or Doldun could be called on account of a rain of frogs. Or Strigli's left running foobar could break a chitinous armor plate and be replaced by a member of team Baz, which means that Baz gets half credit for a Strigli win.
We've had these for a year, I'm sure we all know what to do by now.
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