Re: The Fermi Paradox and SETI Success

On Aug 14, 12:26�pm, John Harshman <jharshman.diespam...@pacbell.net>
wrote:

Kermit wrote:

On Aug 13, 5:12 pm, "K_h" <KHol...@SX729.com> wrote:


<snip>

It seems like once multicelled life evolves, intelligence would be
almost inevitable given sufficient time.


Sure, with the important bit being "sufficient time".


This may turn out to be the limiting factor. I can easily imagine
planets where there aren'*t 4 billion years of stability to allow the
development of intelligence. We may turn out to be outliers in that
respect, which may be the mundane (and ultimately disappointing)
explanation for why we have seen so few visitors (i.e. none).

We are on the edge of the galaxy. Could it be that this is conducive
to fewer disruptive events than planets on stars with nearby
neighbors? Do they have higher rates of radiation - which would be a
problem I would think for complex molecules equivalent to DNA, or more
asteroid strikes?

It's not that NS has any
progressive trend, it's just that it's an attribute which would be a
possible path for a species, given the right variables. Just as larger
animals are inevitable, given that we started very small. Not that
larger is the trend so much as a common direction taken with a random
walk. Look at how many times camouflage, poison, flying, snaring
appendages, armor, and the like evolved. If a plague wiped out humans
this year, there would likely be intelligent tool makers within 20
million years: apes, otters, cephalopods, elephants, cetaceans,
monkeys, parrots all have species comparable to our recent ancestors
in intelligence. (To the degree that the term means *anything in such
disparate species).


I would be interested to know how you figured out that 20 million years
would be "sufficient time".


There are several species who seem to be at the level of intelligence
of our 20 MYA-ancestors (ignoring for the moment what this means for
mollusks and cetaceans), and plenty at the level of our ancestors 100
million years ago. It's not surprising, after all, that our "recent"
ancestors were considerably smarter than our more distant ancestors.
The common ancestor of us all were undoubtedly not very bright... our
line had to pass thru monkey intelligence to get to us. Surely, if
conditions favored it, another line of critters that is comparable to
those ancestors could achieve the same level as we are now, in the
same length of time?

That's where you lose me. It seems to me
that if that were the case, we would have seen additional intelligent
species by now, since cephalopods etc. have been around for quite a bit
longer than 20 million years. That would suggest that "sufficient time"
is quite a bit longer too.


Why? We are simply the first to reach human levels of intelligence (as
far as the evidence shows). But there are many that are as smart as
Cetaceous mammals. I can argue that some cetaceans, apes, and the
elephants are as smart as our 20 MYA-ancestors. Maybe if we don't
interfere, there will be others as smart as we are now in 20 MY or
less.

As many others have pointed out, the other
adaptations you mention have happened convergently many times (except
flight, which has only been achieved 4 times that we know of). Yet
there's only one intelligent species, a quite recent one, and the
absolute minimum necessary for anyone to be there to count.


At one point, there was a first flying species. The first tool-using,
high tech species may interfere, wittingly or unwittingly, with the
development of others - witness the environmental effect we are having
on the planet. I should point out that there was at least one other
intelligent species - neanderthal - who used tools and might have
flown spaceships by now, if we (or something) hadn't somehow wiped
them out.

I don't think you would consider unreasonable the suggestion that if
some virus wiped out bats and birds overnight, that in 20 million
years there might be numerous species of mammals with true flight.

And it took
4 billion years to get that one. By contrast (though only, apparently,
by contrast), multicellularity is easy; it happened at least 5 times
(animals, plants, fungi, red algae, brown algae), more if you're generous.


Any potentially intelligent tools users out there wouldn't have to
start from scratch. Tsk. Sounds almost like something Pitman would
say; but I'm sure I'm just reading you wrong. It is not 4 billion
years from an otter brain to the equivalent of a human brain. Yeast
doesn't pick up rocks to open lunch with, nor use mud slides just to
have fun with.

I can imagine *many reasons why we haven't seen any visitors, and
since we don' t know enough to assign probabilities to these, none of
us are offering anything more than idle speculation.


[snip idle speculation]


Kermit