ARCHAEOPTERYX LOOKS UP
by Frank Wilczek
The New York Academy of Sciences
Update - September/October 2006
Archaeopteryx could fly
—but not very well.
Human beings today
can penetrate outside
Earth’s airy envelope
—but not very well.
Our minds
can penetrate
into realms of thought
far beyond the domain
they were evolved to inhabit
—but not very well.
It seems clear
that the present form
of humanity is,
like archaeopteryx,
a transitional stage.
What will come next?
I don’t know, of course,
but it’s an entertaining, inspiring
—and maybe important—
question to think about.
QUALITATIVE EVOLUTION BASED ON BIOLOGY
In the past,
evolution has been based
on natural selection.
Its results are impressive.
Yet from an engineering perspective,
natural selection is both haphazard and crude
—haphazard because no meaningful goal is explicit;
crude because it gathers feedback slowly and with much noise.
What we might call
its “goal” is simply to keep going.
Its “performance criterion”
is production of fertile off spring:
what Darwin called the struggle for existence.
That “goal” is, of course,
not a mindful goal, nor is
the “performance criterion”
a performance criterion
in the conventional sense,
where we judge how well
some concrete task
has been accomplished.
Yet natural selection,
by allowing information
to flow from the environment
to the replicating unit—the genes—
results in effective adaptation
and creative response to opportunities.
Famously, it leads to
what seems to be inspired designs
to achieve what appear (to us) to be concrete goals.
Viewed analytically,
evolution’s design methods
look terriblyinefficient.
Feedback arrives once a generation,
and its information content is just a few bits,
to wit the number and genetic types
of surviving offspring.
Furthermore,
that information content
is dominated by unrelated noise,
all the complex accidents that impact survival.
By way of comparison,
we routinely gather gigabytes
of useful information every hour
by using our eyes and brain
to look out at the world.
Evolution by natural selection
produces impressive feats
of creative engineering
only because it plays out
over very long spans of time (many generations)
on a very large stage (many individuals).
In the past, eugenics
—encouraging certain individuals
to reproduce while discouraging others—
has been proposed as a path to human improvement.
Even leaving moral issues aside,
classical eugenics was doomed to failure.
Selecting human parents
on the basis of a few superficial characteristics
is inherently crude and inefficient,
with the same drawbacks as natural selection.
Only recently,
with increased
understanding of genetics,
development, and physiology
at the molecular level,
have truly powerful possibilities
for directing evolution begun to arise.
Screening against
catastrophic genetic diseases
is widely practiced and accepted.
But where are
the boundaries between disease,
substandard performance,
and suboptimal performance?
Is deafness a disease?
Is tone deafness?
Is lack of perfect pitch?
Any boundary is artificial,
and arbitrary boundaries will be breached.
What’s in store for the future?
Some, if not all, parents
will seek to produce
the best children they can,
according to their own view of “best.”
Parental (or governmental?) selection
will replace natural selection
as an engine of human evolution.
Selection by genetic screening
will be much more efficient.
What goals will parents pursue?
(Note: I say will, not should.)
The most obvious goal
is improved health, broadly defined
to include both physical vitality and longevity.
The popularity
of performance-enhancing drugs for athletes,
of diets and food supplements, and, of course,
our vast investment in medical research,
attest to our powerful drive toward that goal.
In this area, the most fundamental issue is aging.
After a long exile at the fringes of biology,
the question of why we age,
and what can be done to combat that process,
has now firmly entered the realm of molecular investigation.
Decisive progress
may or may not come within a few years,
but in a few decades it is likely,
and in a century almost certain.
Future humans will be healthier
and live much longer than we do.
They may be effectively immortal
—and they’ll all have perfect pitch.
A second goal is more powerful intelligence.
It may not be obvious,
especially if you pay attention
to the American political scene,
but the evidence of nature
is that there is intense pressure
toward the evolution of increased intelligence.
In the six million years or so
since protohumans
separated from chimpanzees,
even bumbling natural selection
has systematically upgraded our brains
and enlarged our skulls,
despite the steep costs
of difficult childbirth
and prolonged infancy.
I suspect an important part
of the pressure for intelligence
comes from sexual selection:
finding a mate is a complicated business,
and women in particular tend to be choosy.
The salient facts here are:
first, that it was possible
to come so far so fast
(on an evolutionary timescale!),
and second,
that the limiting factor
is plausibly the mechanics of childbirth.
Together, these facts suggest
that tuning up production
of bigger and better brains may be simple,
once we find the tuning mechanism.
More generally,
better understanding
of the molecular mechanisms
behind development and learning
gives new hope for improving mental vitality,
just as understanding molecular genetics
and physiology does for physical vitality.
QUALITATIVE EVOLUTION BASED ON TECHNOLOGY
Biological evolution,
whether based on natural
or parental selection,
is intrinsically limited.
Early design decisions,
that may not be optimal,
were locked in or forced
by the physical nature
of Earth-based life.
Some of those decisions
can be revisited
through the addition
of nonbiological enhancements
(man-machine hybrids);
others may require
starting over from scratch.
The concept of a man-machine hybrid
may sound exotic or even perverse,
but the reality is commonplace.
For example, humans
do not have an accurate time sense,
or absolute place sense,
or the ability to communicate
over long distances or extremely rapidly,
or the ability to record sensory input accurately.
To relieve these deficiencies,
they have already become
man-machine hybrids:
by wearing a watch,
using a GPS system,
and carrying a cell phone,
a Blackberry, and a digital camera.
[Remember this was written in 2006]
Of these devices,
only the watch
was common ten years ago
(and today’s watches
are more accurate and much cheaper).
Many more capabilities,
and more seamless integration
of man and machine,
are on the horizon.
For better or worse,
much of the cutting-edge research
in this area is military.
In other cases,
incremental addition of capability
may not be feasible.
To do justice to what is possible,
radical breaks will be necessary.
I’ll mention three such cases.
The vast bulk of the universe
is extremely hostile to human physiology.
We need air to breathe,
water to drink,
a narrow range of temperatures
to support our biochemistry;
our genetic material
is vulnerable to cosmic radiation;
we do not thrive in a weightless environment.
As a practical matter,
our major ventures into space
will be by proxy.
Our proxies will be
either humans so modified
as to clearly constitute a different species;
or, more likely, new species
we design from scratch,
that will contain
a large nonbiological component.
The fundamental design of human brains,
based on ionic conduction and chemical signaling,
is hopelessly slower and less compact
than modern semiconductor microelectronics.
Its competitive advantages,
based on three-dimensionality,
self-assembly, and fault tolerance,
will fade as we learn how to incorporate
those ideas into engineering practice.
Within a century,
the most capable
information processors
will not be human brains,
but something quite different.
Recently, a new concept has emerged
that could outstrip even these developments.
Physicists have realized
that quantum mechanics
offers qualitatively new possibilities
for information processing,
and even for logic itself.
At the moment,
quantum computers
are purely a theoretical concept
lacking a technological realization,
but research in this area is intense,
and the situation could change soon.
Quantum minds
would be very powerful,
but profoundly alien.
We—and this “we”
includes even highly trained,
Nobel-Prize-winning physicists—
have a hard time
understanding the subtleties
of quantum mechanical entanglement;
but exactly that phenomenon
would be the foundation
of the thought processes
of quantum minds!
WHERE DOES IT LEAD?
A famous paradox
led Enrico Fermi to ask,
with genuine puzzlement,
“Where are they?”
Simple considerations
strongly suggest
that technological civilizations
whose works are readily visible
throughout our Galaxy
(that is, given current
or imminent observation technology)
ought to be common.
If they were,
I’d base my speculations
about future directions of evolution
on case studies!
But they aren’t.
Like Sherlock Holmes’s dog
that did not bark in the nighttime,
the absence of such advanced
technological civilizations
speaks through silence.
Main-sequence stars
like our Sun provide energy
at a stable rate for several billions of years.
There are billions of such stars in our Galaxy.
Although our census of planets
around other stars is still in its infancy,
what we know already
makes it highly probable
that many millions of these stars host,
within their so called habitable zones,
Earth-like planets.
These bodies meet
the minimal requirements for life
in something close to the form we know it,
notably including the possibility of liquid water.
On Earth, the first emergence
of a species capable of technological civilization
took place about one hundred thousand years ago.
We can argue about defining the precise time
when technological civilization itself emerged.
Was it with the beginning of agriculture,
of written language, or of modern science?
But whatever definition we choose,
the number will be significantly less
than one hundred thousand years.
In any case,
for Fermi’s question
the most relevant time
is not ten thousand years,
but closer to one hundred.
This marks the period
of technological “breakout,”
when our civilization
began to release energies and radiations
on a scale that may be visible throughout our Galaxy.
Exactly what that visibility requires
is an interesting and complicated question,
whose answer depends on the means
available to hypothetical observers.
We might already be visible
to a sophisticated extraterrestrial intelligence
through our radio broadcasts
or our effects on the atmosphere.
The precise answer
hardly matters, however,
if anything like the current trend
of technological growth continues.
Whether we’re barely visible
to sophisticated though distant observers today,
or not quite, after another hundred years
of technological expansion we’ll be easily visible.
A hundred years is less
than a part in ten million
of the billion-year span over which
complex life has been evolving on Earth.
The exact placement of breakout within
the multibillion-year timescale of evolution
depends on historical accidents.
With a different sequence
of the impact events
that lead to mass extinctions,
or earlier occurrence
of lucky symbioses
and chromosome doublings,
Earth’s breakout might have occurred
one billion years ago, instead of one hundred.
The same considerations
apply to those other Earth-like planets.
Indeed,
many such planets,
orbiting older stars,
came out of the starting gate
billions of years before we did.
Among the millions of experiments
in evolution in our Galaxy,
we should expect that many
achieved breakout much earlier,
and thus became visible long ago.
So, where are they?
Several answers
to that paradoxical question
have been proposed.
Perhaps our simple estimate
of the number of life-friendly planets
is for some subtle reason wildly overoptimistic.
Perhaps,
even if life of some kind
is widespread,
technologically capable
species are extremely rare.
Perhaps breakout technology
quickly ends in catastrophic
warfare or exhaustion of resources.
There are uncertainties
at every stage of the argument.
Even so, like Fermi, I remain perplexed.
The preceding discussion
suggests another sort of possibility:
they’re out there, but they’re hiding.
QUANTUM QUIET
If the ultimate information processing technology
is deeply quantum-mechanical, it may not be energy-intensive.
Excessive energy use brings heat in its wake,
and heat is a deadly enemy of quantum coherence.
More generally,
quantum information processing
is extremely delicate,
and easily spoiled
by outside disturbances.
It is best done in the cold and the dark.
Quantum minds might well
be silent and isolated by necessity.
Silence and inner contemplation can also be a choice.
The ultimate root of human drives
remains what our selfish genes,
in the struggle for existence, have imprinted.
That root is apparent in many
of our behavior’s most obvious priorities,
which include fending off
threats from a hostile environment,
finding and attracting desirable mates,
and caring for the young.
Those priorities
involve active engagement
with the external world.
The products of deliberate
biological or technological evolution,
as opposed to natural selection,
could have quite different motivations.
They might, for example,
seek to optimize their state
according to some mathematical criterion
(their utility function).
Having found an optimum state,
or several excellent ones,
they could choose ever
to relive selected moments of perfect bliss,
perfectly reconstructed.
This was the temptation of Faust:
If I say to the moment:
“Stay now! You are so beautiful!”
Then round my soul the fetters throw,
Then to perdition let me go!
Humans were not built
to treasure a Magic Moment,
nor could they reproduce
such a moment reliably and in detail.
For our evolutionary successors,
that Faustian temptation
will be much more realistic.
______________________________
Frank Wilczek is the Herman Feshbach
professor of physics at MIT.
He received the Nobel Prize in Physics in 2004
for the discovery of asymptotic freedom
in the theory of the strong interaction.
He is the author, with Betsy Devine,
of Longing for the Harmonies: Themes
and Variations from Modern Physics (W. W. Norton)
and the recently published, Fantastic Realities (World Scientific),
Illustrations that can be seen in:
A cast of the Berlin specimen
of Archaeopteryx lithographica
shows its avian features
(wings, wishbone, feathers)
and its theropod features
(tooth-filled head, lizardlike tail).
A model of Archaeopteryx
lithographica displays
its large wings,
but its lack of a bony breastbone
would have made it a weak flier.
Photos by Ballista.
Cover of the Voyager Golden Record,
launched into space in 1977
on two Voyager spacecraft.
Its sounds and images were selected to
introduce Earth to extraterrestrials.
No hay comentarios:
Publicar un comentario
COMENTE SIN RESTRICCIONES PERO ATÉNGASE A SUS CONSECUENCIAS