It’s definitely the first. The second is bizarre. The third can be steelmanned as “Given my evidence, an ideal thinker would estimate the probability to be 20%, and we all here have approximately the same evidence, so we all should have 20% probabilities”, which is almost the same as the first.
I don’t think it’s only the first. It seems weird to me imagine telling to a group that “There’s a 20% probability that X will occur” if I really have little idea and would guess many of them would have a better sense than me. I would only personally feel comfortable doing this if I was quite sure my information was quite a bit better than theirs. Else, I’d say something like, “I personally think there’s a 20% chance, but I really don’t have much information.”
It’s definitely the first. The second is bizarre. The third can be steelmanned as “Given my evidence, an ideal thinker would estimate the probability to be 20%, and we all here have approximately the same evidence, so we all should have 20% probabilities”, which is almost the same as the first.
I don’t think it’s only the first. It seems weird to me imagine telling to a group that “There’s a 20% probability that X will occur” if I really have little idea and would guess many of them would have a better sense than me. I would only personally feel comfortable doing this if I was quite sure my information was quite a bit better than theirs. Else, I’d say something like, “I personally think there’s a 20% chance, but I really don’t have much information.”