Why don't probabilities come with error margins, or other means of describing uncertainty in their assessments?
If I evaluate a prior probability P(new glacial period starting within the next 100 years) to, say, 0.1, shouldn't I then also communicate how certain I feel about that judgement?
A scientist might make the same estimate but be more sure about it's accuracy than I.
In our everyday judgements we often use such package deals:
A: where's Jamie?
B: I think he went to the club house, but you know Jamie - he could be anywhere.
High P, high uncertainty
A: Where's Susie? Do you think she ran astray after that hefty argument?
B: no I'm certain she would *never* do that. She must have gone to a friends place.
High P, low uncertainty.