"Paul Bramscher" <brams006_nospam@tc.umn.edu> wrote in
message news:cippd3$321$1@lenny.tc.umn.edu...

Anthony Cerrato wrote:

"Paul Bramscher" <brams007_nospam@tc.umn.edu> wrote in
message news:cimpg4$dhk$1@lenny.tc.umn.edu...

Peter Hickman wrote:

Mike Williams wrote:

[snippage]

If there's on thing that's for sure, though, it's that

cities (as a

whole, whatever their rationale) have persisted longer

than radio

communications.  They'll likely last longer than radio

communications,

if current trends in technology continue at such a

breakneck pace.  And

so maybe the most fruitful SETI searches will result

from

(when

technology allows) search for extra-terrestrial cities.

Whether we can

do this optically, chemically or via some other

signature,

a city is not

necessarily required for a sign of intelligence

(hermits,

nomads and

Simak's "City" are counter-examples), but when a city

*is*

found, we

might certainly say that we have found intelligence...

Besides cities have a political dimension. People will

want to be near

the seat of power. Cities will happen if power is

wielded from a given

location. Also population pressure will create cities

as

people simply

have less space between them. Then there is the fact

that large

concentrations of people allow sub cultures to

flourish.

If 1% of the

population like theatre then a town of 1000 people will

probably not

have much of a theatre scene, now 1% of a multimillion

city and you have

a vibrant scene.

The Japanese have a saying about ex pat communities.

1000 people per

restaurant. There will be no decent Japanese restaurant

(that the

Japanese would eat at) until you have at least 1000

people (Japanese) in

the area to frequent it.

Cities are important for the development of

civilizations.

I too think that cities will remain the mainstay of ETIs
derived from _"life as we know it"_ throughout their
lifetime. There is no doubt that the majority of

long-lived

ETI societies would undergo diasporas into interstellar
space (including generation ships and O'Neil type

colonies)

and many will undergo a thinning of population for

various

periods and society-segments due to this dispersion, as

well

as due to improved/rigorous population

control/optimization

techniques/laws (particularly if they develop near
immortality.)

Even for civilizations which develop fears of

exploration or

contact with other ETIs (particularly true with near
immortals) and withdraw to their own planet, and /or
isolated communities or homes, at least some trace(s) of
cities will remain, if only for historical reasons. Even
when societies die off, artifacts of some cities will

remain

for at least some time which might allow detection by
various methods. I do still think though that the

average

lifetime of any such societies (including their

interstellar

colonies) will be far less than the order of, say, a

million

years.

After I wrote my post of the reemergence of the city in

terms of social

usefulness, I read a news article that suggests the

majority of Chinese

city dwellers are in lower-health situations and have a

lower life

expectancy (only 58 years) compared to the national

average of 72.

The Chinese problem is primarily due to politics--the party
has curtailed government social benefits (inc. healthcare)
and employment opportunities for the countryside while
increasing them for the city dwellers. However, it's
certainly true that politics of advanced ETI societies may
well play a big part in how they develop. We often assume
that very advanced societies will, of necessity, be more
rational and socially beneficent, even that technology will
develop a scarcity-free society, but this will not
necessarily always be the case.

And
we can't forget the effects of plagues in Europe.  It may

very well be

that cities are somewhat double-edged swords with regard

to their

utility in light of disease, congestion, stress,

pollutants, etc.

Here also, we usually assume technology will eliminate all
diseases and disabilities of all kind (I like to believe
that any ETI society with a long enough lifetime will
develop immortality techniques--or as Wil McCarthy likes to
call it, since they can occasionally die, immorbidity.) It
also may not be true for a number of reasons. Besides there
probably will never be complete security from the extremely
rare plague which has not been accounted for in a very
long-lived society.

So I wonder if a high-tech alien species will solve this

problem by

dispersal to the countryside, or conquer basic disease,

environmental,

and transportation issues.

On the issue of disease and close proximity, maybe they

(and we?) hope

to achieve bee-like success.  Beehives are widely regarded

as some of

the most sterile naturally occuring places on Earth in our

ordinary

temperature range (between freezing and boiling) because

of propolis.

That's a good point. And with the complete development of
genetic engineering (or alien equivalent,) advanced ETIs may
be able to avoid any such threats.