The Fermi Paradox and SETI Success

On Aug 15, 2:44*am, Tim Tyler wrote:
'Rev Dr' Lenny Flank wrote:

I quite disagree witht his part. *Indeed, I think "intelligence",
particularly in the form of the "technological intelligence" required
for SETI, is an abject evolutionary failure. *In our short tenure as a
species, and even in our microscopic-timed tenure as a technological
species, we've managed to produce the largest mass extinction since
the Cretaceous, and have put not only our own survival as a species at
risk, but the very existence of nearly the entire biosphere within
which we live.

Right. *Six billion humans and going strong and we are a *failure*?!?

What on earth does it take to be a success?
--


How many bacteria are there on earth . . . . . . . . . .. ?


================================================
Lenny Flank
"There are no loose threads in the web of life"

Editor, Red and Black Publishers
http://www.RedAndBlackPublishers.com

Tim Tyler:

Galaxy is 100,000 light years in diameter. Age of universe is
13,730,000,000 years. Aliens who could travel at the speed of
light could zip back and forth across the galaxy some 68,650
times in that time.

Well, yeah, if the Galaxy and the aliens popped into existence at the
instant of the origin of the Universe, along with their planet and with
light-speed spacecraft all ready to go. I know a guy who actually makes
a living traveling around the country preaching something akin to that,
but the figure he uses for the age of the Universe is 6,000 years.

So: the galaxy is pretty small, cosmically speaking - and so the
original interpretation of the Fermi paradox is probably not far
off: if there are intelligent aliens in our galaxy, odds are
they are would be everywhere - so probably there are no aliens
in our galaxy - and SETI is mostly barking up the wrong tree.

I try to stay neutral, I really do. But I think SETI is a waste of time
and money because too many extremely unlikely things have to happen for
success; ET went industrial at just the right time, is not too far
away, invented radio before fiber optics... I understand how much fun
it is for people to speculate. I think there is a very good chance that
we will never know and the speculators will have fun forever.

Me? Thanks for asking. I'm going to proceed on the assumption that ET
is not out there; he is not coming to Earth to
redeem/enslave/eat/liquidate us.

Davoud

--
Don't re-elect the disasters of the past eight years. Vote for the futu
Obama in 2008!

usenet *at* davidillig dawt com

'Rev Dr' Lenny Flank wrote:




How many bacteria are there on earth . . . . . . . . . .. ?

I think mass would be a better measure than number. Still, the insects
outweigh the mammalian population and are better adapted to Earth, as it
is, than mammals.

The first forms of line on this planet were one celled thingies. I
suspect such like organisms will be the last forms of life on this planet.

Bob Kolker

Tim Tyler wrote:



Right. Six billion humans and going strong and we are a *failure*?!?

What on earth does it take to be a success?

Be an ant or a cocroach.

Bob Kolker

On Fri, 15 Aug 2008 10:03:19 -0400, "Robert J. Kolker"
wrote in talk.origins:

'Rev Dr' Lenny Flank wrote:




How many bacteria are there on earth . . . . . . . . . .. ?

I think mass would be a better measure than number. Still, the insects
outweigh the mammalian population and are better adapted to Earth, as it
is, than mammals.

The first forms of line on this planet were one celled thingies. I
suspect such like organisms will be the last forms of life on this planet.

Don't bacteria outweigh insects?

On Aug 14, 12:47*pm, John Stockwell wrote:
On Aug 13, 6:12 pm, "K_h" wrote:



Fermi's paradox suggests that there are little or no other intelligent
civilizations within the Milky Way galaxy. *On the other hand, intelligent
life should exist on a substantial fraction of planets with life because
natural selection broadly increases intelligence with time. *Here on the
Earth, for example, numerous mammals have a high degree of intelligence and
many of them could reach human intelligence with a few more million years of
evolution.

This contradiction can be resolved if the origin of life is far harder than
commonly believed. *That is, in the Drake equation, f_L should be far
smaller than most people think it is. *Even on planets that are life
friendly the formation of life should be extremely rare for the below
reasons.

For life to start, a molecule must arise that can make approximate copies of
itself. *Once that happens then natural selection can work its magic. *But a
molecule that can make approximate copies of itself must be a fairly
sophisticated nano-machine being comprised of dozens, if not hundreds, of
molecules and it must arise via inorganic and non-evolutionary processes.

From the study of DNA and genes, it is known that all life on the Earth has
a common origin (undoubtedly from a molecule of the aforementioned kind).
Since Earth is a life friendly planet, why hasn't another molecule (of the
aforementioned kind) arisen? *If it had, then life on the Earth would have
organisms with two different molecules for genetic codes: DNA and something
else.

Since all Earthly life is based on DNA, this suggests that, over the four
billion years of life on Earth, this has never happened again. *That is,
over the last four billion years, no other molecule has arisen by inorganic
and non-evolutionary processes that can make approximate copies of itself.
And Earth is a life-friendly planet so chances are optimal that such a
molecule should arise.

This suggests that the formation of such a molecule is a very rare event.
In other words, the reaction rate of inorganic chemistry per square meter
times the surface area of the Earth, times the average depth such reactions
take place, times four billion years is , much less, than the number of
such reactions needed before an approximately self reproducing molecule
arises by chance.

If that first molecule had not arisen here on the Earth then the Earth would
probably have been lifeless ever since. *This same reasoning applies if life
first started somewhere else in the solar system and then migrated to Earth
(for example from Mars). *If life rose independently on Mars once, over the
past four billion years, then that suggests that the reaction rate of
inorganic chemistry per square meter, times the surface area of a Mars sized
world, times the average depth such reactions take place, times four billion
years is about the number needed so that an approximately self reproducing
molecule arises by chance once, ~ 1.

It seems too much of a coincidence that the laws of chemistry work out in
such a way that life arises, on average, once per terrestrial world per
several billion years. *Rather, for such cases, it seems much more likely
that life arises multiple times or almost never. *The latter possibility
makes sense from a combinatorial perspective. *A self reproducing molecule
will be composed of dozens to hundreds of other molecules. *But the total
number of permutations for such a molecule's components will far exceed the
total number of inorganic chemical interactions that take place per
terrestrial world per several billion years.

A simple combinatorial thought experiment explains why. *The number of ways
of stacking a deck of playing cards is so huge that if 67.8 billion solar
masses were converted entirely into protons then each proton stands for a
different way of stacking the deck. *But there are 92 naturally occurring
chemical elements and a self reproducing molecule will probably be composed
of hundreds of atoms from the set of 92 different kinds (there only 52 cards
in a playing deck).

So, in the Drake equation, f_L could be something really small like 10^-90.
In this case the fact that life exists on the Earth simply shows that the
universe is super huge and its true size far exceeds the visible universe.

General relativity says that the universe sits on top of an infinite amount
of gravitational potential energy. *During both cosmic inflation and dark
energy inflation the universe falls down its own gravity well converting
huge quantities of its gravitational potential energy into vacuum energy and
expansion energy. *This probably explains why the universe is so huge.

So the universe could contain 10^150 planets, for example. *If f_L is 10^-90
then the total number of planets in the universe that have life is around
10^60. *So there are a lot of planets with life out there but none of them
are close by. *So this is one possible explanation for why there is only one
example of life in the solar system. *And this explanation is consistent
with Fermi's paradox. *It also suggests that any other life in our solar
system got there via migration.

In light of all this, it cannot be concluded that water, oxygen, and
methane, for example, are indicators of extraterrestrial life. *The presence
of these simple gases in the atmospheres of other planets can easily be
explained by inorganic processes.

If Earth is the only planet in 10^150 with life then that suggests that the
universe is fine tuned for Earthly life. *If a substantial fraction of the
10^150 planets have life then that suggests the whole universe is finely
tuned for life. *If the universe if not fine-tuned for life then that
suggests the number of planets with life should be around the logarithmic
middle of 10^150 or around 10^75.

In conclusion, it seems there are lots of planets with life out there but
none of them will ever communicate with humans.

Such arguments are based on using life on earth as a model, but
are also loaded with incorrect notions. First of all, there is no
"doctrine of progress" in evolution. Who says that intelligence is
sellected for? The most successful organisms on the earth are
the dumbest---bacteria---at least "dumbest by our standards".
Of all the human societies that have existed over the past 10,000
years, only one became oriented in the direction of intersteller
communication. We are new on the scene. There is no guarantee
that our culture will retain its high tech ways.

Take, for example, the Olduvai *Theory:http://dieoff.org/page125.htm

which basically is Richard Dunkin's theory
stating *that over the long haul, our
high-population, high-resource demanding culture will
collapse leaving a low population, low resource demanding
stone age culture.

This notion follows other biological growth scenarios that are
governed by the logistic equation. *So, it may be that there
are some flash-in-the-pan high tech worlds out there, that last
a time measured in decades or centuries, and quickly drop
back to that more efficient totally renewable low tech stone age
culture that they sprang from. The Universe could be jam-packed
with human scale intelligent life forms, that are happly chipping
flint into arrowheads and burning wood fires.


Once again, the distinction between correlation and causality must be
explained.

The human population has increased in correlation with technological
innovation. That *does not* mean that if there is a small population,
technology will vanish. Indeed, if the population were to start
dropping tomorrow, it would likely *stimulate* the development of
technology to replace labor.

First-world high-tech high-consumption living standards are perfectly
'sustainable' as long as there are few enough people.

-tg





Or, it could be worse. The universe could be filled with ecologically
spent "Easter Islands", where there are only ruins, and not even
wood to burn.



k

-John

Friar Broccoli wrote:
On Aug 14, 1:06 am, John Harshman
wrote:
Friar Broccoli wrote:
On Aug 13, 8:38 pm, John Harshman
wrote:
K_h wrote:
Fermi's paradox suggests that there are little or no other intelligent
civilizations within the Milky Way galaxy. On the other hand, intelligent
life should exist on a substantial fraction of planets with life because
natural selection broadly increases intelligence with time.

.

Does it? News to me. What evidence do you have that this is the case?

.

There has been an increase in the intelligence of a broad range of
species on earth with time.

Has there? What broad range, exactly? And if natural selection
broadly increased intelligence with time, we would expect all
species to be undergoing this push, wouldn't we?

I don't see how this follows at all. I would expect different
species to adopt widely differing strategies depending on
circumstances. In plants, intelligence would be a complete
waste of resources. Others like Starfish and Jellyfish have
used other strategies to ensure they can navigate and persist in
their environments without needing intelligence.

Exactly. So the blanket statement that there's been an increase in a
broad range of species, because natural selection selects for
intelligence, is wrong. Natural selection occasionally selects for
greater intelligence, sometimes for lesser. There is no general pattern.

Brains are one method for allowing adaptive behaviour which in
turn allows creatures to harvest an often wide range of
resources, while avoiding a wider range of dangers in an
increasingly complex environment. (Not all species need or use
this strategy, just as not all use hard parts, or get really
big or whatever.)

However, there is no general striving, even among those with brains,
toward human-level intelligence. That's my point.

Yet we see that brains exist only in a small subset of species
within one restricted clade (Metazoa), and that, depending on
how you define the word, complex brains exist only in a small
subset of those (which I will choose to interpret here as
Cephalopoda and Gnathostomata), and that particular complex
ones exist only in a small subset of those (Aves and
Mammalia), and that only one species has human-level
intelligence, and from observing usenet, that only rarely.

It's hard to consider this a general trend. Similar results
could be achieved by random diffusion starting at a barrier,
with a great deal of variance in the intelligence of the
extreme tail.

But you don't appear to be arguing a diffusion model. When we
had this same discussion (with respect to the broader measure
complexity - of which intelligence is a subset) and I pointed
out that trees had added complexity; you asserted that that
increase had ended in the Permian.

(that discussion was he
http://groups.google.com/group/talk....0e90c2d77de083)

So you appear to be arguing that such characteristics pop (rather
slowly) into existence and then remain static for the rest of
time. Your entire model bears an eerie similarity to an Old
Earth Creationist model. Are Pagano, Martinez, and Pitman
starting to wear you down?

I agree that the random diffusion model is only a first approximation,
and it doesn't really work that way. Sometimes there are big
innovations, though not at any predictable rate; perhaps "chaotic" is a
better model than "random".

And even if you are arguing a diffusion model it plainly
doesn't fit some obvious facts:

Assuming that brain size as shown in the fossil record is an
adequate surrogate for intelligence (admittedly it is far from
perfect):

If we consider the starting gate for the dinosaurs was the
beginning of the Triassic and the gate for modern mammals the
beginning of the Paleocene then mammals today are
proportionately at the Middle Jurassic, but the brain to body
ratio of the average large mammal vastly exceeds anything the
dinosaurs produced then or at any other time in their history.
And with the exception of the Ratites we don't (as far as I
know) see any large small-brained reptile-like land animals
competing with us.

Furthermore, our own recent evolutionary history in no way
matches a diffusion model. Something caused a spike in primate
brain size about 15 million years ago, and then we saw an even
more dramatic spike during the last 3 million years. I know a
few theories about what drove the latter spike, and while I
don't have the slightest idea, which, if any of them are "true"
it is clear from the abrupt change in slope of the curve that
something was DRIVING that increase.

All more or less true. There was a big increase in mean mammal brain
sizes (controlled for body size) sometime in the Oligocene, if I
remember, usually interpreted as an arms race between predators and
prey. And there have been several episodes of brain size increase in
various primates. Obviously it's not really diffusion, though it
resembles diffusion in gross characteristics. Even in diffusion, if you
want to predict what particles will be in the right tail tomorrow, which
will be further right than the right tail today, you say that some of
the particles in the right tail today are going to make up that new
right tail. The animals with the biggest brains today are likely to be
those with the biggest brains tomorrow, and some may be bigger than they
are today. But in fact the impetus toward bigger brains, even in
primates, seems a rare thing, because the conditions favoring
human-level intelligence are rare, even in primates.

Now returning to the specifics of which groups have done well
in the brain game, it appears to me that we have enough data
points to show an increase in brain size with time:

1- Metazoa/multicellars - begin with no nervous system
Obviously intelligence depends on the development of
multicellularity but that seems to be an inevitable outcome
of evolution given enough time. You said further down that
it occurred at least five times.

"Inevitable" is too strong a word. For one thing, on earth it seems to
have crucially depended on the evolution of eukaryotes, which of course
happened only once, and after several billion years of evolution. It may
be that the most probable outcome is single-celled prokaryotes forever.

Brain development began in three separate lines of multicellular
animal:

2a - Cephalopoda (squids, octopuses)
2b - Gnathostomata (jawed vertebrates)
2c - Arthropod (crabs and insects)

Why 2c? They have no more complex brains than most non-gnathostomes.
There seems to be a level of brain power beyond which it's unlikely to
go, and the ancestral bilaterian may have had that sort of brain.

Your paragraph above mentions aves (together with mammalia) as
achieving exceptional levels of intelligence, but I know of no
work suggesting that birds are smarter than crocodiles, or
sharks (which have a brain/body ratio similar to mammals), or
octopus.

No? My understanding is that modern birds have unusually large
brain/body ratios for archosaurs. Sharks are another possible addition
to the list; hadn't considered them.

So in my book we see significant advances in intelligence in
at least five group lines:

3a - Cephalopoda(squids, octopuses)

And within Gnathostomata:
3b - Sauropsida/reptiles (Crocodiles)
3c - Chondrichthyes (Sharks)
3d - Aves (birds)
3e - Mammals (John Harshman)

Aren't 3b and 3d the same instance, even if you accept 3d? Now in fact
I'd say that within gnathostomes we have no particular increases in
brain power between the root and Sauropsida. So we should leave 3b out.
Still 4, though.

Since Sauropsida began evolving about 300 million years ago and
Aves about 150 million years ago and modern mammals began
seriously diversifying 65 million years ago, we know that the
enhancement of intelligence (or its surrogate - brain size) has
been more or less continuous since the Cambrian although
probably not in all the reference groups over the entire
period.

I would deny that claim. There is no particular increase in brain size
in Sauropsida.

So it seems to me that we have passable physical and
inferential evidence for a steady increase in brain size and
intelligence over time, as well as a plausible model
(adaptation to an increasingly complex and competitive
environment) to explain why it occurred.

I don't think so. We have a few episodes of brain size increase in a few
groups, some of those episodes building on previous episodes. We find
ourselves in a group that has gone through more such episodes than any
other group, but it's always a small subset of each group that undergoes
a new episode, with the possible exception of the Oligocene arms race in
mammals.

Once again, I will ask you for evidence that the self-evident
and expected pattern is not (more or less) the one I am
describing. Can you do any better than:

"I'm wary of claims that anything is self-evident, and
attempts to push the burden of proof onto the negative."

Sure. If the pattern were of a general increase in brain size in animals
in response to an environment of increasing complexity, we would expect
such increases to be broadly distributed over most or all groups.
Instead we get occasional bumps in a few groups. (And I see no sign that
arthropods are more clever now than in the Cambrian.) We certainly see
no trend, even in the groups that have received these bumps, toward
human-level intelligence.

It's very hard to generalize from a single example, which is what all
these probability calculations have to do. And clearly the diffusion
model is wrong in detail. We have two main departures: pre-adaptation
and incumbency.

Some innovations are impossible except in a background of particular,
previous innovations. So we can't talk about intelligence until we have
a multicellular animal with a nervous system. Human-level intelligence
must arise through a series of adaptations of varying probability. We
couldn't possibly have expected it to happen until the evolution of
bilaterians. Which happened only once, and so may be considered unlikely
by the only guide we have. After that crucial event, it took another
half billion years or more to get us; again, doesn't seem a likely thing.

Incumbency would argue in the opposite direction. Perhaps the presence
of a group with a particular innovation fills up that slot and prevents
any other group from achieving it. This certainly happens sometimes.
Maybe the otters are just raring to start chipping stone tools, but we
keep them from it. This too seems unlikely, since we are only a recent
development, and otters have had plenty of time to try it before we
showed up. Hey, we've only been in the Americas for 15,000 years or so.
Where are the American intelligent species? So incumbency, in this case,
doesn't seem to be a credible factor.

Chris.B wrote:
On Aug 15, 1:18 am, John Harshman mumbled:
That was Chris. B's second bizarre, stream-of-consciousness post in this
thread. What newsgroup does he/she usually live in, and is he/she always
like that?


Third. Can someone answer my question?

[snip]

On Aug 14, 12:26*pm, John Harshman
wrote:
Kermit wrote:
On Aug 13, 5:12 pm, "K_h" 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

In talk.origins John Wilkins wrote:
Paul J Gans wrote:

In talk.origins John Harshman wrote:
...
Yes, one solution would be for all civilizations to render themselves
undetectable very soon after becoming detectable. This assumes they
don't go in for travel or communication, and never make noticeable
changes to their habitat (like Dyson spheres and such). It seems to me
that this assumption would require humans to be a very unusual sort of
intelligence, because we're going to go in for communication and travel
as soon as we figure out how, if we don't collapse first.

Other civilizations might well be signalling us like mad using
techniques we've not yet invented.

Or techniques we have abandoned? Semaphores?

Or obviously artificial signals such as the ones that begin:

"I am Mr. Harson Gumbaw, nephew of the reigning oligarch
of Obway. I would like you to join me in a business venture
that will make us both rich..."

--
--- Paul J. Gans