The Fermi Paradox and SETI Success

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.



k

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?

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.

Yes, if there were indeed strong selection pushing them toward greater
intelligence. What makes you think there is?

This contradiction can be resolved if the origin of life is far harder than
commonly believed.

Easier to resolve it by doubting your central claim, that there is a
general trend toward increasing intelligence. The great majority of the
world's living species will not disagree with you, because they're
bacteria without so much as a nerve among them.

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.

Not necessarily. What if DNA is the only reasonable basis? It would be
invented independently more than once. But of course all life we know of
is related. Either life arose here once because it's just that unlikely,
or it arose several times and only one survives (look up coalescence, if
you will), or the first origin to happen changed conditions to make it
unlikely for a second origin to happen. You're going to have to rule out
the other two alternatives if you want to pick the first one. Another
problem is that life arose comparatively soon after the world became
hostpitable to attempts; it doesn't sound that unlikely.

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.

Not true. Earth is now a very life-unfriendly planet. Organic molecules
are eaten before they have much chance to evolve, and that nasty
poisonous oxygen degrades organic compounds.

[snips]

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.

Who says water is an indicator of life? It's only claimed to be
necessary for life. Methane, as far as I know, is never mentioned.
Oxygen is the indicator of life, and if you want to suggest an inorganic
process that can make a lot of free oxygen in an atmosphere, feel free.

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.

That's what we might call number salad. Can you present a real argument
why any of these numbers would mean what you claim?

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

In conclusion? You have just denied the entire rest of your post. First
you claim that life is rare but intelligence is inevitable given life.
And to conclude you claim that life is common but intelligence is rare.
What exactly are you smoking?

On Wed, 13 Aug 2008 17:12:57 -0700, "K_h" wrote:

This contradiction can be resolved if the origin of life is far harder than
commonly believed...

My thinking is that life is easy, and probably common. It's the part
about it becoming (technologically) intelligent that's more likely to be
difficult and rare.

I see nothing to suggest that there are many species on Earth poised to
become technological given a few million years of evolution. Most
species have been around and stable for at least that long. Given the
vast numbers of species on Earth, living and extinct, and the presence
of only one technological one- which happens to be of very recent origin
and likely on the edge of extinction itself- that seems like the weak
link in the Drake chain, and therefore a reasonable answer to the Fermi
Paradox.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

K_h wrote:



Fermi's paradox suggests that there are little or no other intelligent
civilizations within the Milky Way galaxy.

Not to me it doesnt. To me, it simply says either they havent found this
area interesting to explore, or (more likely) its too far to travel.
Even if ET can travel at faster than light, it will take a very very long
time to explore even a small part of the 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.


I also think you're wrong here. If evolution tended to select out the more
intelligent, then (to quote Fermi) "Where are they?" Why are there no other
beings on this entire planet with anything on a par with, or better than,
our level of intelligence?

[ rest of post snipped]

Eric wrote:
K_h wrote:


Fermi's paradox suggests that there are little or no other intelligent
civilizations within the Milky Way galaxy.

Not to me it doesnt. To me, it simply says either they havent found this
area interesting to explore, or (more likely) its too far to travel.
Even if ET can travel at faster than light, it will take a very very long
time to explore even a small part of the galaxy.

A very long time in your terms, yes. But a very short time in the
lifetime of a species. Any species capable of and interested in
interstellar travel, and with the tiniest possible degree of population
increase, will fill the galaxy within a few million years. So either we
are the first, or very close to the first (within a few million years),
or the Fermi Paradox is still a paradox.

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.

I also think you're wrong here. If evolution tended to select out the more
intelligent, then (to quote Fermi) "Where are they?" Why are there no other
beings on this entire planet with anything on a par with, or better than,
our level of intelligence?

And that's his central fallacy. If intelligence were inevitable, there
should be millions of intelligent species on earth. After all, every
other species has been evolving just as long as we have. But most of
them are single-celled prokaryotes; apparently the old ways are best.

In article ,
"K_h" wrote:

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.

There are actually two schools of thought on this. The other one is
called metabolism-first, and holds that a network of chemical reactions
that can transport energy is easier to establish and thus precedes the
self-replication. (I didn't stay at a Holiday Inn, but I do read
Scientific American.)

Another thing you should consider when discussing biochemistry is the
chemist's definition of the word organic. Since we care discussing
biochemistry, I will ask the question in that semantic context: why do
you exclude inorganic molecules and 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.

Any such molecules that showed up late would get eaten.

This suggests that the formation of such a molecule is a very rare event.

No, it suggests that once a particular chemical basis of life gets
established, another one won't.

Unfortunately, that pretty much negates the rest of your argument.

--
Timberwoof me at timberwoof dot com http://www.timberwoof.com
People who can't spell get kicked out of Hogwarts.

On Aug 13, 8:58 pm, Eric wrote:
K_h wrote:

Fermi's paradox suggests that there are little or no other intelligent
civilizations within the Milky Way galaxy.

Not to me it doesnt. To me, it simply says either they havent found this
area interesting to explore, or (more likely) its too far to travel.
Even if ET can travel at faster than light, it will take a very very long
time to explore even a small part of the 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.

I also think you're wrong here. If evolution tended to select out the more
intelligent, then (to quote Fermi) "Where are they?" Why are there no other
beings on this entire planet with anything on a par with, or better than,
our level of intelligence?

[ rest of post snipped]

There is also the problem of a narrow (to date) window for us to
detect them/be detected by them. We have been putting out radio
signals for less than two centuries and really listening for aliens
for about half a century. Even assuming that we would detect signals
not intended for us we would still have to have someone sending a
signal that passed through our area (and lets be liberal in the time
estimate) in the past century. If everybody within a few hundred
light years stopped talking to each other around 1900 AD it would seem
like a uninhabited area. And unless someone can figure out a workable
way around the speed of light limit I really don't expect anything
other than unmanned (unaliened?) probes dropping out of the sky, and
few of them. (They require technology, money (or something like it)
and a desire to explore things.)

Mark Evans

In article ,
Chris L Peterson wrote:

On Wed, 13 Aug 2008 17:12:57 -0700, "K_h" wrote:

This contradiction can be resolved if the origin of life is far harder than
commonly believed...

My thinking is that life is easy, and probably common. It's the part
about it becoming (technologically) intelligent that's more likely to be
difficult and rare.

I see nothing to suggest that there are many species on Earth poised to
become technological given a few million years of evolution. Most
species have been around and stable for at least that long. Given the
vast numbers of species on Earth, living and extinct, and the presence
of only one technological one- which happens to be of very recent origin
and likely on the edge of extinction itself- that seems like the weak
link in the Drake chain, and therefore a reasonable answer to the Fermi
Paradox.

I suspect that just as when one system of biochemistry establishes the
pattern of life, things that use it will eat anything else that shows
up, it is likely that when one highly intelligent species shows up, it
will limit the opportunities for anything else to evolve into sentience.

The final events that drove human evolution to intelligence were all
climatic changes. For example, when forests of Africa became savannah,
the apes that lived there had to adapt, and they ended up going down the
road to high intelligence. It's interesting to note that this also
happened only in once place, and then humans spread out to everywhere.

There are plenty of species running around on the Earth now that are at
about the level of intelligence of our ancestors, oh, twenty million
years ago. They're not likely to develop to sentience any time soon, and
certainly not while we're around unless we help them. (David Brin has
written science fiction novels around that concept ... in his universe
we're a rare event, independently developed sentience. That causes a lot
of political trouble for us in the interstellar culture.) But if we were
to off ourselves suddenly, the Earth would heal and something might have
a chance to develop sentience.

--
Timberwoof me at timberwoof dot com http://www.timberwoof.com
People who can't spell get kicked out of Hogwarts.

In article ,
John Harshman wrote:

Who says water is an indicator of life? It's only claimed to be
necessary for life. Methane, as far as I know, is never mentioned.
Oxygen is the indicator of life, and if you want to suggest an inorganic
process that can make a lot of free oxygen in an atmosphere, feel free.

Only oxygen?

Yeah... it's common and it does some handy chemical reactions. But
similar arguments can be made for water.

--
Timberwoof me at timberwoof dot com http://www.timberwoof.com
People who can't spell get kicked out of Hogwarts.

On Wed, 13 Aug 2008 19:01:27 -0700, Timberwoof
wrote:

In article ,
John Harshman wrote:

Who says water is an indicator of life? It's only claimed to be
necessary for life. Methane, as far as I know, is never mentioned.
Oxygen is the indicator of life, and if you want to suggest an inorganic
process that can make a lot of free oxygen in an atmosphere, feel free.

Only oxygen?

Yeah... it's common and it does some handy chemical reactions. But
similar arguments can be made for water.

Oxygen is reactive enough that oxygen in the atmosphere would be
depleted unless restored from some source. The only likely source is
photosynthesis. Where you have atmospheric oxygen you have living
plants.

Bud