I.
In principle life will begin any
place where the conditions for it are suitable, but the eventual evolution of
an intelligent species, i.e., one possessing what we call would call true
consciousness, is a much more complex proposition, resting as it does on an
increasing number of variables at each emergent level. The number of ways life
can evolve without producing an
intellectually advanced species is formidable, and it is entirely possible that
most life in our Universe is no more advanced than microbes. Even if it becomes
established, an intelligent species may destroy itself in any number of ways;
we might eventually provide our own example of how this is done. Nonetheless,
we may suppose that there are in fact other civilizations which have emerged in
our home galaxy. How numerous such civilizations might actually be is still a
matter of considerable dispute, however. Peter D. Ward and Donald Brownlee have
argued that the number of true civilizations in the Milky Way might be much
lower than we commonly believe. They have come up with a formula which they
believe to be the basis for a realistic estimate. They first discuss the famous
Drake Equation (after astronomer Frank Drake), formulated in the 1950s:
N*
x fs x fp x ne x fi x
fc x fl =N
Where :
N*= stars in the Milky Way Galaxy
fs = fraction of sun-like stars
fp = fraction of stars with planets
ne = planets in a star’s habitable zone
fi = fraction of habitable
planets where life does arise
fc = fraction of planets inhabited by intelligent beings
fl = percentage of a lifetime of a planet that is marked by the presence
of a communicative civilization.
Based on the assumption that
planets are very common, Carl Sagan and other astronomers posited at one time
that the Milky Way contained 1,000,000 communicative civilizations. But Ward
and Brownlee point out that planets may be less common around stars than
initially believed (although a number of exoplanets have been discovered) and
they also point to the complex interaction of variables on our own planet (the
influence of plate tectonics, a low number of mass extinctions, the presence of
a large moon) that may be necessary for the emergence of intelligent life.
Their equation, therefore, looks like this:
N* = stars in the Milky Way Galaxy
fp = fraction
of stars with planets
fpm = fraction of metal-rich
planets
ne = planets in a star’s habitable zone
ng = stars in a galactic habitable zone
fi = fraction of habitable planets where life does
arise
fc = fraction of planets with life where complex
metazoans arise
fl = percentage of a
lifetime of a planet that is marked by the presence of complex metazoans
fm = fraction of planets with a large moon [to
stabilize the tilt of a planet’s axis and to help
stabilize its atmosphere]
fj = fraction of planets with Jupiter-sized planets [ones that
gravitationally attract asteroids
and comets]
fme = fraction of planets
with a critically low number of mass extinction events
Based on these much more rigorous
criteria, Ward and Brownlee estimate that planets where communicative
civilizations emerged are very rare. Even assuming that there are just a few
thousand planets in the Milky Way with any
advanced life might be optimistic. (Pp. 267-275)
In my view, to be pessimistic,
there might be no more than 100 civilizations, including our own in the 100,000
light year diameter of our galaxy. A civilization on average every 1,000 light
years. But multiply this figure by 125 billion or so galaxies (to use a low
estimate), and there may still be more than twelve
trillion civilizations in the Universe. Perhaps it’s not as lonely out
there as we might fear. Even if there is only one civilization per galaxy on average, it still means that the
population of the Universe may be well into the quintillions of intelligent
beings.
What are they like? To say the
least, the images of aliens provided by our popular culture have not, for the
most part, been helpful in answering this question. Any life form must conform
to certain physical boundaries, and perhaps it would be useful to confine
ourselves to examining where these might lie. To
begin with, extraterrestrials are probably three-dimensional (no flat aliens
need apply). As Peter Atkins has pointed out,
nervous systems function most efficiently in three dimensions and in
particular the neuronal interconnectivity with which we associate higher order
intelligence is only possible in such a configuration. It is conceivable that
there are stringy intelligent beings or beings for whom depth has no meaning,
but the probability of them is vanishingly small.
Next, we must assume that
they are neither incredibly tiny nor breathtakingly gargantuan. Different
gravities on different planets would, of course, permit a wide range of sizes
among intelligent creatures, but I would guess the planets where such beings
evolved are probably not characterized by Jupiter-like gravity (which would make
the vertical growth of animals problematic although they could be stretched
very far horizontally). Very low gravity would present difficulties as well, so
such beings probably live on planets that are not radically different from terrestrial size (unless these beings have
re-engineered their home worlds). We should also remember that physical laws
dictate the proportions and dimensions of living things. Intelligent giants
could exist elsewhere. but their structures would still be severely
circumscribed by gravity. There could be enormous cloud-like beings (which has
been speculated by some writers), but as Arthur C. Clarke has pointed out the
speed of their nervous systems would be limited by the speed of light and in
order to function effectively and intelligently their brains would have to be
of a manageable (and inherently limited) size. Physical laws also restrict
smallness of size. There could be very small intelligent beings, but the cells
out of which they are constructed would have to be very small as well, and
cells are pretty tiny as it is. If we assume that brains need large numbers of
cells to develop intelligence, it would seem to rule out a race of intelligent
creatures the size of a spider monkey. And yes, we should forget about worlds
of intelligent creatures who live around atoms. (A wonderful discussion of such
matters is found in Clarke's Profiles of
the Future.) Therefore, we should not expect that aliens would be many
orders of size different from ourselves, although there could be a great deal
of variation. (Witness the difference between our tallest giants and the
smallest dwarves.)
We should probably assume
that intelligent beings are not photosynthetic (and hence not plants) and thus
they would need to ingest material for their metabolic processes. (Yes, we
might indeed be appetizing to them.) If they do need to eat in the sense we
understand it that means they must be mobile in some way. We must also assume
that they have some way of manipulating the physical objects around them. If
they couldn't do so, it’s hard to see how they could construct a civilization
unless they were telekinetic (which I strongly doubt somehow). Dolphins and
whales on our own planet are highly intelligent beings but they are not
technological. Their inability to grasp and manipulate objects precludes this.
(So does this mean our alien friends live on land rather the water? Not
necessarily. but it might be easier for them if they did.) Therefore,
extraterrestrials probably have appendages of some sort, although these could
be of a startling variety of sizes, shapes, and flexibility.
They would also have to
have some sort of sensory apparatuses for detecting the energies which flow and
undulate around all of us. Their primary sense for navigating the physical world
might not always be sight, however. As Richard Dawkins has pointed out, bats
construct a sonic reality which is as vivid to them as visual reality is to us.
Therefore, alien eyes might not always be as acute as ours (or even exist, for
that matter). If they are of a race which evolved eyes, those eyes may be
adapted to perceive different parts of the light spectrum than our own. They
may be multiple in number (although two eyes are handy in the construction of a
visual field which permits depth perception). Other sensory apparatuses which
they may have evolved or given themselves through genetic engineering may allow
them to perceive various forms of radiation, signals transmitted directly from
other brains, or forms of energy the existence of which we might not suspect.
Of course, the above limits
leave a lot of room for variation. What are their body chemistries? Are they
carbon based, like terrestrial life forms, or are they perhaps based on silicon
or some other element which bonds readily to form organic molecules? Are they
based on nucleic acids of some sort? Do any of them resemble terrestrial
mammals or could there be intelligent creatures which resemble Earth’s
amphibians or reptilians in appearance (or even its birds, for that matter)? Is
it possible that there are multiple
species of intelligent, culture-possessing, symbol-manipulating beings on some
of these planets? Do the beings of other worlds have lung-like structures or do
they process atmospheric gases in some other way? What are their brains like?
Do their brains, like ours, reflect their species' evolutionary history, and if
so are these beings mixtures of instinctive, emotional, and intellectual
behaviors? How do their brains process and transmit language? Have any of them
figured out a way to transcend physical bodies altogether and exist as pure
intelligence (which strikes me as improbable, but who knows)? One thing is
certain: they don’t look like us. The odds against this are so prohibitive that
we needn't concern ourselves with it. Any science fiction which portrays aliens
as human-like in their appearance strikes me as being particularly
unimaginative.
II.
But
aside from my child-like curiosity about the possible appearance and physical
features of extraterrestrial intelligent beings, there are deeper issues with
which I’d like to deal. Is there a set of rules that would apply to any
intelligent, consciousness-possessing, sentient being anywhere in this or any other possible Universe, rules which would
arise naturally from the very nature of
mind itself? I ask this not
because I think we will ever encounter such beings—I consider the odds of this
happening to be remote—but rather to try to connect us intellectually and
emotionally to a larger reality than ourselves, and to see our moral rules in a
new perspective.
We must imagine that
intelligent creatures everywhere possess awareness of the impact of their
actions on others and thus (in some way) have a moral and ethical sense. It’s
difficult to see how they could interact with each other if they didn’t. (In
that sense, an ethical system has utility.
It serves as a minimal social good.) If they, like us, evolved in part
through physical struggle and violence, have they learned how to overcome their
violent tendencies? How do they get along with each other now in light of their
own past histories? In how many ways have moral issues been resolved, and what
kinds of sufferings and sacrifices were necessary to bring about these
resolutions? Have others been able to achieve the precarious balance between
the rights and integrity of the individual and the needs of a broader social
group? Is there a universal sense of right and wrong, a sense of empathy
perhaps based on phenomena similar (although obviously not identical) to the
mirror neurons in our own brains?
More ominously, are there
planets where the doctrine of Might-Makes-Right has triumphed to the exclusion
of all other possible ethical systems? Has the utility of evil proven so
alluring that there are planetary civilizations that are nightmare worlds of
oppression, savagery, violence, suffering, and uninhibited cruelty? On our own
planet the grim history of would-be world conquerors must give us at least some
pause. The impulse toward mass murder and mass enslavement still rests in the
darkest recesses of some of our fellow humans’ minds. There is at least the
possibility that such horror may yet engulf us. There is a very real
possibility that it has engulfed others elsewhere.
Moreover, in the course of
the social evolution of other
intelligent species, did they evolve belief systems that were planet-centric,
ones that placed them at the center of creation, as did ours? Did their planets
tend to develop several different belief systems, and if so, did their worlds undergo
the agonizing religious clashes we have seen on ours? If there are indeed
multiple intelligent species on these planets, how did they learn to co-exist?
There may have been terrible racial wars, true inter-species conflicts that
scarred the history of these worlds. How have the civilizations which may have
experienced such events managed to overcome their deleterious effects?
In attempting to address
such questions, we must assume, I believe, that any intelligent species
anywhere in any frame of reference:
A. Is the product of some
sort of organic evolution in which reproductive success was of paramount
importance.
B. Is sentient in some way
and to some degree, and this sentience is the product of its evolutionary
inheritance.
C. Is descended from ancestors who had to figure
out the rules of their planet from scratch, just as ours did, and discovered
the true nature of their world haltingly, over a great period of time.
D. Has ancestors for whom
survival involved certain difficulties and hardships, and for whom certain
rules of conduct were indispensable.
E. Has undergone a long
process of social evolution which has not always proceeded smoothly, and which
may have involved a significant amount of interpersonal violence and other
upheavals.
Therefore, an ethical
system anywhere in the Universe or Multiverse might rest on the following
assumptions:
1. The awareness of the self.
Assumption: The survival and physical well-being of the self is
desirable, and hence a being has the fundamental right to acquire those things
that are essential for its survival and to defend itself.
2. Emotional attachment to a kinship group. Assumption: The security
and survival of a being’s family, especially its offspring, is a matter of
vital concern.
3. Group Identity. Assumption: The well-being of the broader group of
which a being is a member is a vital concern, in light of the group’s likely
importance to the survival of the being and its in-groups.
4. Group cohesion. Assumption: Intra-group violence is generally
counter-productive and something to be discouraged. Rules of conduct must
therefore exist and be enforced.
5. Unregulated Group Relations. Assumption: Ordinary interaction
between members of a group must rest on interpersonal trust, lest chaos and anarchy
come to prevail.
There are other assumptions
which could be made, of course, but to me these seem to be the most fundamental
ones, inasmuch as they are directly related to the reproductive success of the
individual and the group of which it is a member.
A group somewhere in the
Multiverse may take into consideration other ideas, over and above the basic
assumptions, ones which encompass a much wider range of beings. A truly
advanced ethical system anywhere might embrace such propositions as:
1. All sentient beings are as real as any
others, and since they are sentient,
have the capacity to experience both pleasure and suffering. Conversely, I am
as real as any other sentient being, and I have a right to expect other
intelligent beings to be cognizant of this fact and act accordingly.
2. Our sympathies must not lie entirely with our
own group, our own kind of being, or our own culture. They must extend to all
others. We have a right to expect reciprocity in this matter. Our empathy must
extend as widely as possible as well.
3. We must never seek to
deliberately impose needless suffering on any sentient being, and we must never inflict suffering on others who
are innocent of any offense against us.
4. We must respect the
world upon which we live, and preserve it for those who will come after us.
5. We must grant to all
sentient beings the right to make of themselves what they can, within the
boundaries of respect for other sentient beings.
Again, there are others,
but in my view these all represent a step beyond the basic ethical principles.
If a civilization embraces the doctrine of mutual respect among its members, it
has genuine hopes of avoiding a future of endless brutality and the horrific
reality of “the war of all against all”.
A major complication which
might alter these assumptions is the possibility that the intelligent life form
of some other world might be machine-based, the product of what we would call
artificial intelligence. In that case, we would have to assume that such entities
are the successors of organic beings. They would be the indirect product of organic evolution, a sort of secondary offshoot
of it. Such machine-based intelligence would have undergone its own
evolutionary path, but it might have been a very rapid one, as it has been on
this planet, and the machines may in fact have aided and directed their own
evolution significantly. Whether an AI entity is capable of consciousness is an
issue, as we have seen, that has yet to be resolved. From an ethical standpoint,
would an AI entity be a person, some one
instead of some thing? And would an
AI entity have any capacity for empathy or respect for the survival of others?
Would such entities have goals and purpose? Would they evolve an interior
emotional life, or is such a question merely the product of one human’s
inability to conceive of consciousness on any basis but his own?
III.
How many histories are
taking place out there? How many wars, migrations, scientific and technological
revolutions, religious movements, artistic developments, empires rising and
falling have there been? How many philosophies have been generated? What
explanations have the Aristotles, Lao-Tzus, Siddharthas, and Augustines of
other planets come up with for the mysteries of existence? In how many
civilizations is a god of some sort worshipped? lf there is in fact a single
universal God, has He (or it) played out a series of huge cosmic dramas with
the intelligent beings of other planets in ways similar to those believed by
Jews, Muslims, and Christians to be taking place on this planet? (Have there
been, in countless number, prophets? Messiahs? Saviors? Resurrections?) In how
many ways is love expressed? Hatred? Passion? Artistic sensibility? We must
imagine that somewhere, every conceivable act of which intelligent beings are
capable is happening right now (in
our frame of reference), from the most deeply spiritual and altruistic to the
most atrociously horrible. In a sense, in various parts of the Universe or
Multiverse, our entire experience is being recapitulated at any given moment.
This is a reality I can't see but it overwhelms me just in its contemplation.
It may be extremely
unlikely we will ever directly encounter any other intelligent,
language-possessing species. But in the most general sense, we should
acknowledge them as fellow perceivers of the Universe, and wish them well in
their pursuit of knowledge of it. From an ethical standpoint, we must regard
any extraterrestrial intelligent beings as persons.
This means, if we endow persons on Earth with certain rights and
considerations, that these extraterrestrials would deserve the same. We must
know that even though we may never encounter them, that they are as real as we,
and by virtue of that fact, deserving of our sympathies and respect. We must
hope that they feel the same way. In that sense, perhaps, we might know each
other after all.
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