From: Rafal Smigrodzki (rafal@smigrodzki.org)
Date: Tue Jun 03 2003 - 10:38:06 MDT
Hal Finney wrote:
>
> If you started off confident that humans would survive because so many
> other peoples have done it, the analysis of the DA ought to shake your
> confidence at least somewhat. It ought to cause you to revise your
> estimate downward of the human race's chances for success. Your early
> birth rank is evidence against a successful human diaspora. You may
> still believe that it can happen, if the evidence from alien success
> is even greater than the odds-against generated by the DA. But
> still, you have to count the DA as evidence in the negative
> direction. And that's all that the DA asks, that you take it into
> consideration and revise your estimates downward.
### I fully agree here. The DA should indeed reduce the estimate I might
have of our civilization surviving much longer.
However, I do not have a clear estimate of civilization lifespan. We have so
little data, that any lifespan between a few thousand years and infinity is
possible (cannot be excluded with some plausible reasoning). I do not have
an intuition, no definite prior about whether sentient species usually fail
before spreading in space, or not. Therefore, reducing my estimate downwards
has very little meaning - a non-number reduced by a finite ratio is still a
non-number.
As I wrote before, the DA tries to wring too much understanding out of too
little data, and its use in decision-making is very limited. Also, I don't
think it can be an argument for pessimism and long-range defeatism, as some
people (not you) are applying it.
Rafal
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