[extropy-chat] Re: cosmic silence

[Russell Wallace]

On Fri, 18 Feb 2005 10:26:29 -0800 (PST), Mike Lorrey <mlorrey at yahoo.com> wrote:
> 
> Well, I believe NASA has something to dispute with you. They now claim
> that alien life is most likely now living on Mars:

I'm aware of that result, but:

1) Methane is also produced by nonbiological processes, so all the
presence of methane on Mars actually tells us is that either there is
life on Mars or there is not - which isn't exactly news.

2) Even if there is life on Mars, that doesn't constitute evidence for
it having evolved more than once in our solar system, because we know
material has been transmitted between the planets in conditions such
that it could have carried viable spores.

3) Even if we were to find evidence of life having evolved more than
once, this wouldn't constitute evidence that it evolves intelligence
in more than, say, 1e-100 of cases. (On Earth, life appeared more or
less as soon as it could have, and intelligence appeared more or less
as late as it could have, which is what we would expect to see if the
evolution of intelligence is more difficult. Of course, this is still
consistent with the probability of life being 1e-100 and the
probability of intelligence given life being 1e-200.)

I'll try once more: why do you want aliens to exist? Why do you regard
the idea that they don't exist as "pessimism"?

- Russell