But isn't it reasonable to suggest that the death of one man in the set would then change the P("being a man")? Or perhaps if we're measuring the probability between islands of populations and find a variation in the P("being a man")?
In this sense, the filtration is an uncertain condition...
In that example, the filtration is the information that there are 1 woman and 9 men.
So in actual fact, P("being a man" | \scriptstyle \mathcal{F} = {"1 woman and 9 men"}) = 9/10, or under a simplified notation, P("being a man") = 9/10.
If the filtration is changed to "2 women and 8 men", then...
I am somewhat annoyed by the term "unconditional probability", in that all probabilities are indeed conditional on filtration (an information set if you would like), without which, a probability is inadequately defined as though plucked out of thin air based on no logical information.
I make...