Re: poly: What probabilities?

Nick Bostrom, <bostrom@ndirect.co.uk>, writes:
> Depending on which sense of probability we have in mind, we might
> give very different numerical estimates. Consider the question: "What
> is the probability that nanotechnology will cause the extinction of
> earth-descendent intelligent life?"
> [...]
> In sense 2, I might say: "I don't know, but I would guess somewhere
> between 2% and 70%."

When dealing with an uncertain event, is there any more information to
give once you have specified your best guess at the probability? Given
the question above, where you are uncertain between 2% and 70%, suppose
that if you were forced to pin it down you would say 25%.

Is there a difference between situations where you are "certain" the
chance is 25%, and situations where you are uncertain, but the best
guess is 25%?

To describe the chances of a future event, does probability need
error bars? Should we have to draw a normal-shaped curve showing the
probability that we think a certain probability is correct? (And if so,
does it stop there, or do we need to further qualify the probability
that we give to the probabilities?)

This question has come up on the FX (idea futures) game, where people
are betting on the probability of future events. Is it significant
whether there is a strong market consensus that a certain probability
is about right, versus a claim where there is a broader range of
values which have support?

Hal
Received on Sun Apr 26 21:40:49 1998