[ExI] Bayesian epistemology

[Technotranscendence]

On Monday, August 06, 2007 7:32 AM Russell Wallace
russell.wallace at gmail.com wrote:
> 3) We should express uncertainty by making up numbers and calling them
> probabilities.
>
> There are situations where this is the right thing to do. What's the
> probability that a fair coin will come up heads? 0.5. What's the
> probability that I will die this year? I don't know, but life
> insurance companies have tables that could be consulted for a number,
> which could reasonably be interpreted as a probability _because it is
> based on statistical data_.
>
> But Bayesianism encourages us to make up numbers where there is no
> such data. Not only do we not have any basis for calling these numbers
> probabilities, but we have excellent reason to refrain from doing so.
> One study showed that statements to which people attached "90%
> confidence" were right about 30% of the time; nor is this at all
> atypical.

I think the problem matches up with the difference, in economics,
between risk and uncertainty (Knight) as well as between plain vanilla
ignorance and sheer ignorance (Lachmann).  On the former dyad, risk is
quantifiable unknowns while uncertainty is not quantifiable.  On the
latter, an example might be I don't know how many symphonies Mozart
wrote, but I _know_ I don't know that, while there are many things I'm
not even aware that I _don't know_ I don't know.

Regards,

Dan