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Why
has the earth not been colonized from outside, although any
developed technological civilization should be able to diffuse
through the galaxy within a few million years? Mainly two answers
have been proposed:
(1) We are alone (or nearly so)
because some narrows along the path towards our level of
complexity make the appearance of intelligence or civilization
extremely unlikely events. A whole universe (or even multiverse?)
is then needed to let this possibility become realized on just
one planet.
(2) Technological civilization itself is the
narrows. Either it becomes selfdestructive through global
ecological (or social) disaster, or it succeeds in
self-organizing technological restriction. Then, mind might be a
long-lived phenomenon but renounce the spatial expansion of its
own physical structure.
The first answer has been favoured
by Brandon Carter, Frank Tipler and many others. Carter’s
probabilistic argument [1, 2] is impressive at the first glance:
A crossing of the narrows must be extremely unlikely, because
otherwise it would have happened much earlier; that it happened
only “near the end” (at about half the life-time of
the sun) appears then as a natural implication of the fact “that
we are here”.
The weakness of Carter’s
argument lies in the fact that many known and unknown processes
on earth happen on time-scales similar to that of solar
evolution. Present knowledge may not even be sufficient to
exclude the possibility that the decay of some abundant
radioactive nuclides was necessary before life or nervous systems
could reach their present level of complexity. Similarly, the
decreasing frequency of large volcanic eruptions and of
collisions with interplanetary bodies might have played a role,
as well as the slow shaping of Gaia’s crust and atmosphere
as parts of the biosphere. Therefore, the idea that
“intelligence” is likely to appear on “habitable
planets” after a few billion years is still compatible with
Carter’s argument.
Tipler [3] argued that “the
most solid experimental fact” in this whole discussion
is the absence of foreign explorers or conquerers throughout the
earth’s history. In his opinion this makes the SETI project
comparable to ESP-research: “Virtually any motivation we
can imagine that would lead extraterrestrial intelligences to
engage in interstellar radio communication with us would also
motivate them to engage in interstellar travel. In particular,
radio communication is colonization of other inhabited star
systems by memes (idea complexes) from alien star systems. If one
pposed on moral grounds colonization by genes (via interstellar
travel), one would also oppose colonization by memes (via radio).
Interstellar colonization either by genes or by memes necessarily
implies biological evolution on an interstellar scale: The first
intelligent species to originate will occupy all ecological
niches available to it, a behaviour pattern adopted by all
species that ever existed on the earth. …” [3].
Obviously, Tipler assumes that mind’s ecological niches
would have to be found in physical space. “What have
they been doing these billions of years?”, he asks –
but isn’t this a childish question? Even human mind has
already discovered quite different spaces for inward instead of
outward expansion. And even some human minds do communicate with
others without wishing to “colonize” them. Mind is a
new front of evolution in the space of possibilities, not
“property” of some individuals or species or
cultures.
From arguments like Tipler’s we can
certainly not exclude the possibility that there are
intelligences around and communicate with each other. Concerning
the present and future attempts of search for extraterrestrial
intelligence (SETI), Jill Tarter said [4]: “It’s
technology which we are trying to detect – not
intelligence”. This very relevant remark leads us to the
right track to answer the question “Where are they?”,
even if we don’t think we are necessarily alone.
I
have often argued [5] that technology itself is the narrows along
the way to further mental evolution, because there is a purely
logical upper limit to the speed of growth of complexity, and
that so-called technological civilization surpasses that limit,
thus destroying the conditions for further “creation of
values”. Even worse, from the theory of creation, i.e.
self-organization, there follows what I called the
“devil-theorem”: In a spatially finite system with
unbounded evolution the speed of innovation must increase until a
global instability sets in.
Why is that so? We do have a
“solid experimental fact” (just look at the present
situation of the earth), but we can gain more general insight by
thinking about time and complexity. To remember what complexity
is, consider the number of possible “relation structures”
for a set of points with one line or no line between any two of
them. How many points are needed to let the number of such
possible structures surpass the number of baryons in our observed
universe? The answer is: 24 points! How, then, have viable
structures at all been found and kept any stability for some
time? How is the history of our universe and all its details
being selected? This single realized line in a practically
infinite-dimensional space of possibilities? It started from an
extremely special global state (“big Bang”) which
offered immense “fossil” resources and sinks for
later self-organization. (The two main sources of free energy are
“fossils of the first few minutes”: Because things
were thrown apart, they stored gravitational potential energy
with respect to each other, which can be re-gained in the
formation of lumps, and, because expansion was initially so fast,
there wasn’t time to go beyond Hydrogen and Helium, the
fossil fuels in stars.) Ever since this unlikely beginning, the
unavoidable fluctuations have been exploring neighbouring
possibilities. Since there are so many of them, there are
probably “better” ones found, more viable ones –
if there is time enough to test the relevant relations between
the new and the old. More viable possibilities survive by
definition. A hierarchy of dissipative structures emerges, with
more and more mutual adaptation, which also includes relative
isolation as far as possible. The tautological principle of this
Darwinian co-evolution is: “Probably, something more likely
is going to happen”. This is the meaning of time, the drive
behind the growth of complexity in our universe – up to the
speed-limit.
Does this mean that the “better”
(the more complex, which we find more valuable) arises without
any value-judgement? No, the selection process is the
value-judgement, and its principle is the same on the levels of
physical, chemical, biological and mental evolution. One can
easily see why the emerging world is hierarchical. Structures on
lower levels, the viability of which has long been tested, will
be used on higher levels with little modification because
attempts to “improve” them must introduce many
untested interactions nd, therefore, probably lead to break-down.
With too many new relations (remember the 24 points!) time is not
sufficient to try them out, and no viable new structures will be
found, even if they might be possible. Building upon time-tested
feed-back loops is more successful. Still, a crisis is
unavoidable.
At any moment, there is a “front of
evolution in the space of possibilities”, where innovation
proceeds fastest. This speed is itself an “evolutionary
success” and is likely to grow until feed-back with the
whole becomes insufficient. Then, this front collapses, but
evolution goes on with whatever diversity is left. Of course, we
cannot formulate a general system-theoretical argument which
would allow us to call certain developments “safe” in
the sense that they will not destroy there own roots. However,
even with the absurd assumption that the front might succeed in
complete emancipation from its roots and the whole, a logical
limit to the speed of creation of values is self-evident: The
level of complexity reached has to be “relearned by each
generation”. Thus, the critical speed is roughly defined by
“essential change within the life-time of the individual
structures at the front”. If the (r)evolutionary process of
fluctuation and selection gropes its way into the space of
possibilities faster than that, the leading sub-systems cannot
even take into account their own complex value. Self-organization
of global simplicity sets in and increases the speed of “wrong”
value-judgements further. Within a few generations of the leading
sub-structures they start destroying themselves and the viability
of the whole system from which they evolved.
As I wrote
elsewhere [6]: “ … Evolution itself defines and
creates a critical time-scale, which it then necessarily tries to
surpass. But thereby it must destroy its own logical
preconditions. The leading figures at the front of evolution
don’t give themselves enough time to judge values in the
process of exploring the neighbourhood in the space of
possibilities. Of course, the tautology remains valid that “more
likely things will probably be realized” via the accidental
fluctuations (including their more recent form of appearance,
called planning) – but with a lack of time for selective
adaptation, i.e. adaptive selection, the more likely is no longer
a growth of complexity but rather its decomposition. In a very
sophisticated way, the entropy law seems to have conquered the
Earth, an open dissipative system in which we thought it wouldn’t
be valid. While everybody was still worrying and quarreling about
the resources, we have been filling up and blocking the sinks
…”
This kind of instability is quite
similar to the “success” of a fast-growing water-lily
on a pond, or of a cancer-cell in an individual organism. The
characteristic difference, however, lies in the “globality”.
If the system is isolated or spatially finite in the sense that
the time-scale for communication with the outside is long
compared to the time-scale of the instability, no revival from
“outside ponds” and no survival of “outside
individuals” will stop or heal the local disaster. A black
hole will remain, or scorched earth.
If
evolution doesn’t stop due to external influences, this
onset of global instability is probably unavoidable. Growth of
evolutionary speed itself seems to be an evolutionary success as
long as the errors can be pushed to the “borders” –
i.e. until the global scale has been reached. This acceleration
must certainly take place when evolution on a planet reaches the
level of mental structures. The “discovery” (i.e.
“detection”, i.e. “apo-kalypse”) of the
laws of nature will start technological progress because this
provides more power. Of course, like in our own history, many
individual minds will understand the “devil-theorem”
quite early, since the laws of logic are more fundamental
than the laws of nature. But in the fight between “God
and Devil”, dia-bolos (i.e. “he who throws things
into disorder”) will prevail because he is always quicker
than the creator of true complexity.
Thus, any planet with
intelligence is likely to run into our kind of technological
crisis and to approach global ecological or social disaster.
Still, I call it a crisis, and not the end. When deadly
consequences of this “progress” are felt on the
critical time-scale (the own life-time) by a majority, insight
into the logical pre-conditions of creation may become dominant
in the global society of minds. It may then still be possible to
self-organize the restriction of power and of the speed of
innovation, and to shift the front of evolution to the mind –
where creation of new complexity is possible without the
destruction of its whole basis.
Conclusions concerning
SETI are obvious. If there are others in our universe, they will
not be interested in simple material structures, except during a
few generations before that crisis. Mind will recognize itself as
infinitely more complex, i.e. valuable. Topics like astronomy
would play a negligible role in an “Encyclopedia
Galactica”. If civilizations transmit signals, they will
probably not use “variations of something expected”,
as William Calvin proposed here “because radio-astronomers
are interested in pulsars” [4]. For mind the only
interesting thing in the universe will be other mind. Even the
“acquisition signals” (though probably on “magic
frequencies” – e.g. as favoured by David Blair [7]
might not be perceptible on the human timescale – another
relevant remark by Jill Tarter [4].
Civilizations beyond
the acceleration-crisis would not try and help others to overcome
it, too. Not because they are selfish, but because such help is
obviously impossible. They must know that many of us have
understood the origin of the crisis, but that we can stop only
(if at all) at the very edge of the abyss. The time-scale of
interstellar communication is longer than that of our
instability. After the development of radio-technology there is
no time left for help. Earlier interference, however, before the
onset of the instability, would not mean help but colonization –
which is probably excluded by further mental evolution (or even
by a fundamental incompatibility between long-distance space
travel and a “mastering of the Devil”). Hence, there
is nothing important which we could learn from aliens on the
time-scale of the crisis, i.e. on the human time-scale. It’s
all in our minds! Still, the discussion about whether we should
listen or not, and why we don’t hear anything, may
contribute a little to the understanding of the devil-theorem …
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References
[1]
Brandon Carter, “The anthropic principle and its
implications for biological evolution”, Phil. Trans. R.
Soc. Lond. A310, 347-363 (1983).
[2] John D. Barrow and Frank
J. Tipler, The Anthropic Cosmological Principle, Oxford
University Press, New York 1986.
[3] Frank J. Tipler, Letter
to Physics Today, Sept. 1988, pp. 88 and 146.
[4] Panel
discussion, 3rd Intern. Symp. on Bioastronomy, Val Cenis 1990,
Bioastronomy (J. Heidmann, M. J. Klein Eds.), Springer,
Berlin 1991.
[5] First in “On the World’s Ends”,
preprint 1976 (publ. in Munich Social Science Review 1978/2,
91-99), last in Das Grundgesetz vom Aufstieg,
Carl-Hanser-Verlag, München 1989.
[6] “Time and
Complexity” in Proceedings of the Workshop on Gravita-
tion, Magneto-Convection and Accretion at the Ringberg
Castle, Tegernsee, May 28-31, 1989 (B. Schmidt, H.-U. Schmidt,
H.-C. Thomas Eds.), Max-Planck-Inst. Proc. MPA/P2, Sept 1989.
(Included as No. 2 in this collection of essays.)
[7]
David Blair, in Bioastronomy, see [4].
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