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C00002 00002	%long[f89,jmc]		The long term prospect for humanity
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%long[f89,jmc]		The long term prospect for humanity

	It's hard to see how humanity can survive more than
$10↑50$ years, give or take a factor of 2 in the exponent.  Even
that might require drastic concentration of intelligence in an
artificial system that would carry on what our descendants might
regard as the essence of human-descended life.

	If we want humans like the present ones, living on
planets like the present ones, illuminated by suns like the
present ones, then $10↑25$ is perhaps the limit.

	Giving up the planets but preserving human form may
give $10↑30$ years.

	Let us suppose that the scientific picture relevant
to human survival remains the same for billions of years.
Our descendants will probably take the same view of the
eventual doom of the species that a person takes of his own
death.  Death is a misfortune to be put off as long as possible,
but in the meantime there are many interesting and worthwhile
things to do.

	The present solar system is good for a few times $10↑9$,
but new stars, not too different from our own may be forming
up to $10↑20$ years from now.

	The human population of the solar system can grow quite
a lot for those of our descendants willing to live in space.
For example, the energy output of the sun would support $10↑26$
people using it with present day efficiency.

	Maybe we would find some other reason not to let our
population grow that large, but remember that there are likely
to be many human societies, more diverse than society is now,
and some of them may have reasons to grow quite large.

	I should admit favoring this diversity and am repelled
by Utopias of any kind postulating uniformity and control of
emigration.  Indeed the one thing that is likely to motivate
humanity to last a long time is diversity of human society.

	With the technologies based on present day science
with which I am confident, journeys to nearby stars will take
high hundreds to low thousands of years, thus requiring
multi-generation journeys with present human biology.  I'm
sure some of us will undertake them even if there is no
alternative and humanity will occupy the galaxy in a few
hundred thousand years if we aren't limited by encountering
other civilizations.  The tribes that do the travelling
will be aided by continuous transmissions from home
and needn't fall behind intellectually more than the
distance enforced by the speed of light.

	Laser powered systems permitting substantial fractions
of the velocity of light also seem plausible.

	However, most likely biology will give us much
longer lives within a few hundred years, and this will completely
change the psychology of long voyages as well as other
aspects of human psychology and sociology.

	Very likely it will also be possible to send robots
ahead of us to transform other stellar systems to our liking,
but maybe we'll all prefer to reserve the adventures for humans.
That's a long shot because of the afore-mentioned multiplicity
of societies.

	The settlement of the solar system is somewhat overdue to
my impatient mind.  If we in the U.S. had set our minds to it, we
could have colonized an asteroid by now.  If this had been done,
we would begin to know how people born there feel about life
in space, when they would be inclined to declare their independence,
and how fast they could or would expand from their own resources.
Future historians, however, will consider the delay that annoys
me as not worth mentioning.

	Fortunately, the U.S. is not the only country in the
world, and the world-wide assumption that new ventures are
first undertaken in the U.S. or the Soviet Union will die off
in the next 10 or 20 years, and there will be 20 countries
capable of vigorous space exploration and colonization.
Some of them will do it, and the U.S. will follow suit.
Indeed the first steps could be done for amounts of money
corresponding to that major universities raise in major
fund drives, i.e. it could be done with U.S. or Japanese
private donated money.  This money might be easier to get
than investments.

	As for the earth itself, I think it will progress about
as it has done since World War II, with more countries drawn into
democratic capitalist expanding economies.  An enormously
destructive major war is still possible but increasingly
unlikely.  Humanity would even survive such a war, and would
reach the same point in a few hundred years that it would reach
without it.

	Many ecological dooms are being urged on us, but I
believe that what real substance there is in the warnings
will be met with essentially minor changes in our way of
life.  If we had a world government, it would be possible
for an ideological fad like the belief in environmental
doom to be warded off by symbolic sacrifices to conquer
the world.  Fortunately, there seems to be sufficient
variety of countries for them not all to go crazy at
once.

	There's plenty of nuclear energy for a few billion
years, and other substances can be concentrated with the
use of energy when concentrated ores run out.  Methods of
expanding food supply exist for any likely population expansion
in the next 200 years, and that gives our smart descendants
plenty of time to figure out what to do.  Our concrete proposals
will be regarded the way we regard projections made in the
middle of the nineteenth century.

	My only reason for discussing the long term future is
to establish that our civilization is in its extreme infancy
relative to its expected life.

	When humanity expands beyond the earth, it will become
clear that the earth should be regarded as a garden rather than
as a wilderness with humanity one among many species.  We will
arrange the earth as we find most convenient and aesthetic.
Fortunately, the earth is large and we prize variety.  Some parts
will be wild, but most will be tamed in a much greater variety of
ways than we can presently imagine.

	However, even within the solar system, there will be
other gardens.  For example, both Mars and Venus can be moved
into the earth's orbit and given earthlike atmospheres and
climates.  Some people already have figured out how these
things can be done.  If you want to figure out how to do it
well, you'd better study mathematics, science and engineering.