[extropy-chat] Drake Equation nitpicking

[Adrian Tymes]

--- Mike Lorrey <mlorrey at yahoo.com> wrote:
> If one technological civilization exists at any time
> in the entire
> history of each universe and develops sim tech, then
> odds are massively
> in favor of the simulation argument.

Only if the sim includes other races.

> N = R* x fp x ne x fl x fi x ft x fs
[corrected to remove fc as well]
>  
> where:
>  
> N is the number of extraterrestrial civilizations
> that exist at any
> time in the history of our universe which we might
> expect to be able to
> go posthuman and create simulated universes.

Ah - "be able to", or "actually do"?  And the concepts
of posthuman and creating sim universes aren't
necessarily linked - though, of course, it's fair to
ask specifically about just those races who do both.

>  and
>  
>  
>  R* is the rate of star formation in our universe
>  fp is the fraction of those stars which have
> planets 
>  ne is average number of planets which can
> potentially support 
>     life per star that has planets

Might want to include moons in that.  E.g., it appears
that (ne x fl) might be at least 4 in this solar
system's case: Venus, Earth, Mars, and Titan.

>  fl is the fraction of the above which actually go
> on to develop life
>  fi is the fraction of the above which actually go
> on to develop
>     intelligent life
>  ft is the fraction of the above which survive to
> post-human
>     equivalent technological development
>  fs is the fraction of the above which develop and
> use universe
>     simulation technologies to replicate their own
> past history
>     or made-up histories.
> 
> (You can call this the Lorrey Equation ... ;)) It is
> quite clear that
> if we are talking about a volume of space as huge as
> the entire
> universe, then the odds of N exceeding 1 are
> extremely large. As soon
> as N meets 0.5 (half of natural universes have one
> such civilization),
> then the odds of us living in a simulated universe
> exceeds 50%. The
> odds increase asymptotically as N approaches 1.
> Beyond N=1, you are
> dealing with the mathematics of infinitely large
> probabilities, i.e.
> sure things, tautologies.

Not necessarily.  The terms ft and fs both seem to be
essentially unknown (despite unjustified claims that
fs in particular and maybe also ft are both 1), and it
seems like (R* x fp x ne x fl x fi) <= 1 for the
volume of space we have observed so far, possibly for
the entire galaxy.