June 26, 2003
What are the burning issues for you currently?
Well, several things. Professionally, I work on something called Superstring
theory, or now called M-theory, and the goal is to find an equation, perhaps
no more than one inch long, which will allow us to "read the mind of God,"
as Einstein used to say.
In other words, we want a single theory that gives us an elegant, beautiful
representation of the forces that govern the Universe. Now, after two
thousand years of investigation into the nature of matter, we physicists
believe that there are four fundamental forces that govern the Universe.
Some physicists have speculated about the existence of a fifth force, which
may be some kind of paranormal or psychic force, but so far we find no
reproducible evidence of a fifth force.
Now, each time a force has been mastered, human history has undergone a
significant change. In the 1600s, when Isaac Newton first unraveled the
secret of gravity, he also created a mechanics. And from Newton's Laws and
his mechanics, the foundation was laid for the steam engine, and eventually
the Industrial Revolution.
So, in other words, in some sense, a byproduct of the mastery of the first
force, gravity, helped to spur the creation of the Industrial Revolution,
which in turn is perhaps one of the greatest revolutions in human history .
The second great force is the electromagnetic force; that is, the force of
light, electricity, magnetism, the Internet, computers, transistors, lasers,
microwaves, x-rays, etc.
And then in the 1860s, it was James Clerk Maxwell, the Scottish physicist at
Cambridge University, who finally wrote down Maxwell's equations, which
allow us to summarize the dynamics of light .
That helped to unleash the Electric Age, and the Information Age, which have
changed all of human history . Now it's hard to believe, but Newton's
equations and Einstein's equations are no more than about half an inch long.
Maxwell's equations are also about half an inch long. For example, Maxwell's
equations say that the "four-dimensional divergence of an antisymmetric,
second-rank tensor equals zero." That's Maxwell's equations, the equations
for light . And in fact, at Berkeley, you can buy a T-shirt which says, "In
the beginning, God said the four-dimensional divergence of an antisymmetric,
second rank tensor equals zero, and there was Light , and it was good."
So, the mastery of the first two forces helped to unleash, respectively, the
Industrial Revolution and the Information Revolution.
The last two forces are the weak nuclear force and the strong nuclear force,
and they in turn have helped us to unlock the secret of the stars, via
Einstein's equations E=mc 2, and many people think that far in the future,
the human race may ultimately derive its energy not only from solar power,
which is the power of fusion, but also fusion power on the Earth, in terms
of fusion reactors, which operate on seawater, and create no copious
quantities of radioactive waste.
So, in summary, the mastery of each force helped to unleash a new revolution
in human history .
Today, we physicists are embarking upon the greatest quest of all, which is
to unify all four of these forces into a single comprehensive theory. The
first force, gravity, is now represented by Einstein's General Theory of
Relativity, which gives us the Big Bang, black holes, and expanding
universe. It's a theory of the very large; it's a theory of smooth,
space-time manifolds like bedsheets and trampoline nets.
The second theory, the quantum theory, is the exact opposite. The quantum
theory allows us to unify the electromagnetic, weak and strong force .
However, it is based on discrete, tiny packets of energy called quanta,
rather than smooth bedsheets, and it is based on probabilities, rather than
the certainty of Einstein's equations. So these two theories summarize the
sum total of all physical knowledge of the physical universe .
Any equation describing the physical universe ultimately is derived from one
of these two theories. The problem is these two theories are diametrically
opposed. They are based on different assumptions, different principles, and
different mathematics . Our job as physicists is to unify the two into a
single, comprehensive theory. Now, over the last decades, the giants of the
twentieth century have tried to do this and have failed.
For example, Niels Bohr, the founder of atomic physics and the quantum
theory, was very skeptical about many attempts over the decades to create a
Unified Field Theory. One day, Wolfgang Pauli, Nobel laureate, was giving a
talk about his version of the Unified Field Theory, and in a very famous
story, Bohr stood up in the back of the room and said, "Mr. Pauli, we in
the back are convinced that your theory is crazy. What divides us is whether
your theory is crazy enough."
So today, we realize that a true Unified Field Theory must be bizarre, must
be fantastic, incredible, mind -boggling, crazy, because all the sane
alternatives have been studied and discarded.
Today we have string theory, which is based on the idea that the subatomic
particles we see in nature are nothing but notes we see on a tiny, vibrating
string. If you kick the string, then an electron will turn into a neutrino.
If you kick it again, the vibrating string will turn from a neutrino into a
photon or a graviton. And if you kick it enough times, the vibrating string
will then mutate into all the subatomic particles.
Therefore we no longer in some sense have to deal with thousands of
subatomic particles coming from our atom smashers, we just have to realize
that what makes them, what drives them, is a vibrating string. Now when
these strings collide, they form atoms and nuclei, and so in some sense, the
melodies that you can write on the string correspond to the laws of
chemistry. Physics is then reduced to the laws of harmony that we can write
on a string. The Universe is a symphony of strings. And what is the mind of
God that Einstein used to write about? According to this picture, the mind
of God is music resonating through ten- or eleven-dimensional hyperspace,
which of course begs the question, "If the universe is a symphony, then is
there a composer to the symphony?" But that's another question.
What do you think of Sir Martin Rees' concerns about the risk of creating
black holes on Earth in his book, Our Final Hour?
I haven't read his book, but perhaps Sir Martin Rees is referring to many
press reports that claim that the Earth may be swallowed up by a black hole
created by our machines. This started with a letter to the editor in
Scientific American asking whether the RHIC accelerator in Brookhaven, Long
Island, will create a black hole which will swallow up the earth. This was
then picked up by the Sunday London Times who then splashed it on the
international wire services, and all of a sudden, we physicists were deluged
with hundreds of emails and telegrams asking whether or not we are going to
destroy the world when we create a black hole in Long Island.
However, you can calculate that in outer space , cosmic rays have more
energy than the particle s produced in our most powerful atom smashers, and
black holes do not form in outer space. Not to mention the fact that to
create a black hole , you would have to have the mass of a giant star. In
fact, an object ten to fifty times the mass of our star may in fact form a
black hole . So the probability of a black hole forming in Long Island is
However, Sir Martin Rees also has written a book, talking about the
Multiverse. And that is also the subject of my next book, coming out late
next year, called Parallel Worlds . We physicists no longer believe in a
Universe . We physicists believe in a Multiverse that resembles the boiling
of water. Water boils when tiny particles, or bubbles, form, which then
begin to rapidly expand. If our Universe is a bubble in boiling water, then
perhaps Big Bangs happen all the time .
Now, the Multiverse idea is consistent with Superstring theory, in the sense
that Superstring theory has millions of solutions, each of which seems to
correspond to a self-consistent Universe . So in some sense, Superstring
theory is drowning in its own riches. Instead of predicting a unique
Universe, it seems to allow the possibility of a Multiverse of Universes.
This may also help to answer the question raised by the Anthropic Principle.
Our Universe seems to have known that we were coming. The conditions for
life are extremely stringent. Life and consciousness can only exist in a
very narrow band of physical parameters. For example, if the proton is not
stable, then the Universe will collapse into a useless heap of electrons and
neutrinos. If the proton were a little bit different in mass, it would
decay, and all our DNA molecules would decay along with it.
In fact, there are hundreds, perhaps thousands, of coincidences, happy
coincidences, that make life possible. Life, and especially consciousness,
is quite fragile. It depends on stable matter, like protons, that exists for
billions of years in a stable environment, sufficient to create
autocatalytic molecule s that can reproduce themselves, and thereby create
Life. In physics, it is extremely hard to create this kind of Universe. You
have to play with the parameter s, you have to juggle the numbers, cook the
books, in order to create a Universe which is consistent with Life .
However, the Multiverse idea explains this problem, because it simply means
we coexist with dead Universes. In other Universes, the proton is not
stable. In other Universes, the Big Bang took place, and then it collapsed
rapidly into a Big Crunch, or these Universes had a Big Bang, and
immediately went into a Big Freeze, where temperatures were so low, that
Life could never get started.
So, in the Multiverse of Universes, many of these Universe s are in fact
dead, and our Universe in this sense is special, in that Life is possible in
this Universe. Now, in religion, we have the Judeo-Christian idea of an
instant of time, a genesis, when God said, "Let there be light ." But in
Buddhism, we have a contradictory philosophy, which says that the Universe
is timeless. It had no beginning, and it had no end, it just is. It's
eternal, and it has no beginning or end.
The Multiverse idea allows us to combine these two pictures into a coherent,
pleasing picture. It says that in the beginning, there was nothing, nothing
but hyperspace, perhaps ten- or eleven-dimensional hyperspace. But
hyperspace was unstable, because of the quantum principle. And because of
the quantum principle, there were fluctuations, fluctuations in nothing.
This means that bubbles began to form in nothing, and these bubbles began to
expand rapidly, giving us the Universe . So, in other words, the
Judeo-Christian genesis takes place within the Buddhist nirvana, all the
time, and our Multiverse percolates universes.
Now this also raises the possibility of Universes that look just like ours,
except there's one quantum difference. Let's say for example, that a cosmic
ray went through Churchill's mother, and Churchill was never born, as a
consequence. In that Universe, which is only one quantum event away from our
Universe, England never had a dynamic leader to lead its forces against
Hitler, and Hitler was able to overcome England, and in fact conquer the
So, we are one quantum event away from Universes that look quite different
from ours, and it's still not clear how we physicists resolve this question.
This paradox revolves around the Schrödinger's Cat problem, which is still
largely unsolved. In any quantum theory, we have the possibility that atoms
can exist in two places at the same time, in two states at the same time.
And then Erwin Schrödinger, the founder of quantum mechanics , asked the
question: let's say we put a cat in a box, and the cat is connected to a jar
of poison gas, which is connected to a hammer, which is connected to a
Geiger counter, which is connected to uranium. Everyone believes that
uranium has to be described by the quantum theory. That's why we have atomic
bombs, in fact. No one disputes this.
But if the uranium decays, triggering the Geiger counter, setting off the
hammer, destroying the jar of poison gas, then I might kill the cat. And so,
is the cat dead or alive? Believe it or not, we physicists have to
superimpose, or add together, the wave function of a dead cat with the wave
function of a live cat . So the cat is neither dead nor alive.
This is perhaps one of the deepest questions in all the quantum theory, with
Nobel laureates arguing with other Nobel laureates about the meaning of
Now, in philosophy, solipsists like Bishop Berkeley used to believe that if
a tree fell in the forest and there was no one there to listen to the tree
fall, then perhaps the tree did not fall at all. However, Newtonians believe
that if a tree falls in the forest, that you don't have to have a human
there to witness the event.
The quantum theory puts a whole new spin on this. The quantum theory says
that before you look at the tree, the tree could be in any possible state.
It could be burnt, a sapling, it could be firewood, it could be burnt to the
ground. It could be in any of an infinite number of possible states. Now,
when you look at it, it suddenly springs into existence and becomes a tree.
Einstein never liked this. When people used to come to his house, he used to
ask them, "Look at the moon. Does the moon exist because a mouse looks at
the moon?" Well, in some sense, yes. According to the Copenhagen school of
Neils Bohr, observation determines existence.
Now, there are at least two ways to resolve this. The first is the Wigner
school. Eugene Wigner was one of the creators of the atomic bomb and a Nobel
laureate. And he believed that observation creates the Universe. An infinite
sequence of observations is necessary to create the Universe, and in fact,
maybe there's a cosmic observer, a God of some sort, that makes the Universe
spring into existence .
There's another theory, however, called decoherence, or many worlds, which
believes that the Universe simply splits each time , so that we live in a
world where the cat is alive, but there's an equal world where the cat is
dead. In that world, they have people, they react normally, they think that
their world is the only world, but in that world, the cat is dead. And, in
fact, we exist simultaneously with that world.
This means that there's probably a Universe where you were never born, but
everything else is the same. Or perhaps your mother had extra brothers and
sisters for you, in which case your family is much larger. Now, this can be
compared to sitting in a room, listening to radio. When you listen to radio,
you hear many frequencies. They exist simultaneously all around you in the
room. However, your radio is only tuned to one frequency. In the same way,
in your living room, there is the wave function of dinosaurs. There is the
wave function of aliens from outer space. There is the wave function of the
Roman Empire, because it never fell, 1500 years ago.
All of this coexists inside your living room. However, just like you can
only tune into one radio channel, you can only tune into one reality
channel, and that is the channel that you exist in. So, in some sense it is
true that we coexist with all possible universe s. The catch is, we cannot
communicate with them, we cannot enter these universes.
However, I personally believe that at some point in the future, that may be
our only salvation. The latest cosmological data indicates that the Universe
is accelerating, not slowing down, which means the Universe will eventually
hit a Big Freeze, trillions of years from now, when temperatures are so low
that it will be impossible to have any intelligent being survive.
When the Universe dies, there's one and only one way to survive in a
freezing Universe, and that is to leave the Universe . In evolution, there
is a law of biology that says if the environment becomes hostile, either you
adapt, you leave, or you die.
When the Universe freezes and temperatures reach near absolute zero, you
cannot adapt. The laws of thermodynamics are quite rigid on this question.
Either you will die, or you will leave. This means, of course, that we have
to create machines that will allow us to enter eleven-dimensional
hyperspace. This is still quite speculative, but String theory, in some
sense , may be our only salvation. For advanced civilizations in outer
space, either we leave or we die.
That brings up a question. Matrix Reloaded seems to be based on parallel
universes. What do you think of the film in terms of its metaphors?
Well, the technology found in the Matrix would correspond to that of an
advanced Type I or Type II civilization. We physicists, when we scan outer
space , do not look for little green men in flying saucers. We look for the
total energy outputs of a civilization in outer space, with a characteristic
frequency. Even if intelligent beings tried to hide their existence , by the
second law of thermodynamics, they create entropy, which should be visible
with our detectors.
So we classify civilizations on the basis of energy outputs. A Type I
civilization is planetary. They control all planetary forms of energy . They
would control, for example, the weather, volcanoes, earthquakes; they would
mine the oceans, any planetary form of energy they would control. Type II
would be stellar. They play with solar flares. They can move stars, ignite
stars, play with white dwarfs. Type III is galactic, in the sense that they
have now conquered whole star systems, and are able to use black holes and
star clusters for their energy supplies.
Each civilization is separated by the previous civilization by a factor of
ten billion. Therefore, you can calculate numerically at what point
civilizations may begin to harness certain kinds of technologies. In order
to access wormholes and parallel universe s, you have to be probably a Type
III civilization, because by definition, a Type III civilization has enough
energy to play with the Planck energy .
The Planck energy, or 10 19 billion electron volts, is the energy at which
space-time becomes unstable. If you were to heat up, in your microwave oven,
a piece of space-time to that energy, then bubbles would form inside your
microwave oven, and each bubble in turn would correspond to a baby Universe.
Now, in the Matrix , several metaphors are raised. One metaphor is whether
computing machin s can create artificial realities. That would require a
civilization centuries or millennia ahead of ours, which would place it
squarely as a Type I or Type II civilization.
However, we also have to ask a practical question: is it possible to create
implants that could access our memory banks to create this artificial
reality, and are machines dangerous? My answer is the following. First of
all, cyborgs with neural implants: the technology does not exist, and
probably won't exist for at least a century, for us to access the central
nervous system . At present, we can only do primitive experiments on the
For example, at Emory University in Atlanta, Georgia, it's possible to put
glass implant into the brain of a stroke victim, and the paralyzed stroke
victim is able to, by looking at the cursor of a laptop, eventually control
the motion of the cursor. It's very slow and tedious; it's like learning to
ride a bicycle for the first time. But the brain grows into the glass bead,
which is placed into the brain. The glass bead is connected to a laptop
computer, and over many hours, the person is able to, by pure thought,
manipulate the cursor on the screen.
So, the central nervous system is basically a black box. Except for some
primitive hookups to the visual system of the brain, we scientists have not
been able to access most bodily functions, because we simply don't know the
code for the spinal cord and for the brain . So, neural implant technology,
I believe is one hundred, maybe centuries away from ours.
Will robots take over?
On the other hand, we have to ask yet another metaphor raised by the Matrix,
and that is, are machine s dangerous? And the answer is, potentially, yes.
However, at present, our robots have the intelligence of a cockroach, in the
sense that pattern recognition and common sense are the two most difficult,
unsolved problems in artificial intelligence theory. Pattern recognition
means the ability to see, hear, and to understand what you are seeing and
understand what you are hearing. Common sense means your ability to make
sense out of the world, which even children can perform.
Those two problems are at the present time largely unsolved. Now, I think,
however, that within a few decades, we should be able to create robots as
smart as mice, maybe dogs and cats. However, when machines start to become
as dangerous as monkeys, I think we should put a chip in their brain, to
shut them off when they start to have murderous thoughts.
By the time you have monkey intelligence, you begin to have self-awareness,
and with self-awareness, you begin to have an agenda created by a monkey for
its own purposes. And at that point, a mechanical monkey may decide that its
agenda is different from our agenda, and at that point they may become
dangerous to humans. I think we have several decades before that happens,
and Moore's Law will probably collapse in 20 years anyway, so I think
there's plenty of time before we come to the point where we have to deal
with murderous robots, like in the movie 200 .
So you differ with Ray Kurzweil 's concept of using nanobots to reverse-
engineer and upload the brain, possibly within the coming decades?
Not necessarily. I'm just laying out a linear course, the trajectory where
artificial intelligence theory is going today. And that is, trying to build
machine s which can navigate and roam in our world, and two, robots which
can make sense out of the world. However, there's another divergent path
one might take, and that's to harness the power of nanotechnology. However,
nanotechnology is still very primitive. At the present time, we can barely
build arrays of atoms. We cannot yet build the first atomic gear, for
example. No one has created an atomic wheel with ball bearings. So simple
machines, which even children can play with in their toy sets, don't yet
exist at the atomic level. However, on a scale of decades, we may be able to
create atomic devices that begin to mimic our own devices.
Molecular transistors can already be made. Nanotubes allow us to create
strands of material that are super-strong. However, nanotechnology is still
in its infancy and therefore, it's still premature to say where
nanotechnology will go. However, one place where technology may go is inside
our body. Already, it's possible to create a pill the size of an aspirin
pill that has a television camera that can photograph our insides as it goes
down our gullet, which means that one day surgery may become relatively
In the future , it's conceivable we may have atomic machines that enter the
blood. And these atomic machines will be the size of blood cells and perhaps
they would be able to perform useful functions like regulating and sensing
our health, and perhaps zapping cancer cells and viruses in the process.
However, this is still science fiction, because at the present time, we
can't even build simple atomic machines yet.
Are we living in a simulation?
Is there any possibility, similar to the premise of The Matrix , that we are
living in a simulation?
Well, philosophically speaking, it's always possible that the universe is a
dream , and it's always possible that our conversation with our friends is a
by-product of the pickle that we had last night that upset our stomach.
However, science is based upon reproducible evidence. When we go to sleep
and we wake up the next day, we usually wind up in the same universe . It is
reproducible. No matter how we try to avoid certain unpleasant situations,
they come back to us. That is reproducible. So reality, as we commonly
believe it to exist, is a reproducible experiment, it's a reproducible
sensation. Therefore in principle, you could never rule out the fact that
the world could be a dream, but the fact of the matter is, the universe as
it exists is a reproducible universe.
Now, in the Matrix, a computer simulation was run so that virtual reality
became reproducible. Every time you woke up, you woke up in that same
virtual reality. That technology, of course, does not violate the laws of
physics. There's nothing in relativity or the quantum theory that says that
the Matrix is not possible. However, the amount of computer power necessary
to drive the universe and the technology necessary for a neural implant is
centuries to millennia beyond anything that we can conceive of, and
therefore this is something for an advanced Type I or II civilization.
Why is a Type I required to run this kind of simulation? Is number crunching
Yes, it's simply a matter of number crunching. At the present time, we
scientists simply do not know how to interface with the brain. You see, one
of the problems is, the brain, strictly speaking, is not a digital computer
at all. The brain is not a Turing machine. A Turing machine is a black box
with an input tape and an output tape and a central processing unit. That is
the essential element of a Turing machine: information processing is
localized in one point. However, our brain is actually a learning machine;
it's a neural network.
Many people find this hard to believe, but there's no software , there is no
operating system, there is no Windows programming for the brain . The brain
is a vast collection, perhaps a hundred billion neurons, each neuron with
10,000 connections, which slowly and painfully interacts with the
environment. Some neural pathways are genetically program med to give us
instinct . However, for the most part, our cerebral cortex has to be
reprogrammed every time we bump into reality.
As a consequence, we cannot simply put a chip in our brain that augments our
memory and enhances our intelligence .Memory and thinking, we now realize,
is distributed throughout the entire brain For example, it's possible to
have people with only half a brain . There was a documented case recently
where a young girl had half her brain removed and she's still fully
So, the brain can operate with half of its mass removed. However, you remove
one transistor in your Pentium computer and the whole computer dies. So,
there's a fundamental difference between digital computers--which are easily
program med, which are modular, and you can insert different kinds of
subroutines in them--and neural networks, where learning is distributed
throughout the entire device , making it extremely difficult to reprogram.
That is the reason why, even if we could create an advanced PlayStation that
would run simulations on a PC screen, that software cannot simply be
injected into the human brain, because the brain has no operating system.
Ray Kurzweil's next book, The Singularity is Near, predicts that possibly
within the coming decades, there will be super-intelligence emerging on the
planet that will surpass that of humans. What do you think of that idea?
Yes, that sounds interesting. But Moore's Law will have collapsed by then,
so we'll have a little breather. In 20 years time, the quantum theory takes
over, so Moore's Law collapses and we'll probably stagnate for a few decades
after that. Moore's Law, which states that computer power doubles every 18
months, will not last forever. The quantum theory giveth, the quantum theory
taketh away. The quantum theory makes possible transistors, which can be
etched by ultraviolet rays onto smaller and smaller chips of silicon. This
process will end in about 15 to 20 years. The senior engineers at Intel now
admit for the first time that, yes, they are facing the end.
The thinnest layer on a Pentium chip consists of about 20 atoms. When we
start to hit five atoms in the thinnest layer of a Pentium chip , the
quantum theory takes over, electrons can now tunnel outside the layer, and
the Pentium chip short-circuits. Therefore, within a 15 to 20 year time
frame, Moore's Law could collapse, and Silicon Valley could become a Rust
This means that we physicists are desperately trying to create the
architecture for the post-silicon era. This means using quantum computers,
quantum dot computers, optical computers, DNA computers, atomic computers,
molecular computers, in order to bridge the gap when Moore's Law collapses
in 15 to 20 years. The wealth of nations depends upon the technology that
will replace the power of silicon.
This also means that you cannot project artificial intelligence
exponentially into the future. Some people think that Moore's Law will
extend forever; in which case humans will be reduced to zoo animals and our
robot creations will throw peanuts at us and make us dance behind bars. Now,
that may eventually happen. It is certainly consistent within the laws of
However, the laws of the quantum theory say that we're going to face a
massive problem 15 to 20 years from now. Now, some remedial method s have
been proposed; for example, building cubical chips, chips that are stacked
on chips to create a 3-dimensional array. However, the problem there is heat
production. Tremendous quantities of heat are produced by cubical chips,
such that you can fry an egg on top of a cubical chip . Therefore, I firmly
believe that we may be able to squeeze a few more years out of Moore's Law,
perhaps designing clever cubical chips that are super-cooled, perhaps using
x-rays to etch our chips instead of ultraviolet rays. However, that only
delays the inevitable. Sooner or later, the quantum theory kills you. Sooner
or later, when we hit five atoms, we don't know where the electron is
anymore, and we have to go to the next generation, which relies on the
quantum theory and atoms and molecules.
Therefore, I say that all bets are off in terms of projecting machine
intelligence beyond a 20-year time frame. There's nothing in the laws of
physics that says that computers cannot exceed human intelligence. All I
raise is that we physicists are desperately trying to patch up Moore's Law,
and at the present time we have to admit that we have no successor to
silicon, which means that Moore's Law will collapse in 15 to 20 years.
So are you saying that quantum computing and nanocomputing are not likely to
be available by then?
No, no, I'm just saying it's very difficult. At the present time we
physicists have been able to compute on seven atoms. That is the world's
record for a quantum computer . And that quantum computer was able to
calculate 3 x 5 = 15. Now, being able to calculate 3 x 5 = 15 does not equal
the convenience of a laptop computer that can crunch potentially millions of
calculations per second. The problem with quantum computers is that any
contamination, any atomic disturbance, disturbs the alignment of the atoms
and the atoms then collapse into randomness. This is extremely difficult,
because any cosmic ray, any air molecule, any disturbance can conceivably
destroy the coherence of our atomic computer to make them useless.
Unless you have redundant parallel computing?
Even if you have parallel computing you still have to have each parallel
computer component free of any disturbance. So, no matter how you cut it,
the practical problems of building quantum computers, although within the
laws of physics, are extremely difficult, because it requires that we remove
all in contact with the environment at the atomic level. In practice, we've
only been able to do this with a handful of atoms, meaning that quantum
compute s are still a gleam in the eye of most physicists.
Now, if a quantum computer can be successfully built, it would, of course,
scare the CIA and all the governments of the world, because it would be able
to crack any code created by a Turing machine. A quantum computer would be
able to perform calculations that are inconceivable by a Turing machine.
Calculations that require an infinite amount of time on a Turing machine can
be calculated in a few seconds by a quantum computer . For example, if you
shine laser beams on a collection of coherent atoms, the laser beam
scatters, and in some sense performs a quantum calculation, which exceeds
the memory capability of any Turing machine .
However, as I mentioned, the problem is that these atoms have to be in
perfect coherence, and the problems of doing this are staggering in the
sense that even a random collision with a subatomic particle could in fact
destroy the coherence and make the quantum computer impractical.
So, I'm not saying that it's impossible to build a quantum computer; I'm
just saying that it's awfully difficult.
SETI: looking in the wrong direction
When do you think we might expect SETI [Search for Extraterrestrial
Intelligence] to be successful?
I personally think that SETI is looking in the wrong direction. If, for
example, we're walking down a country road and we see an anthill, do we go
down to the ant and say, "I bring you trinkets, I bring you beads, I bring
you knowledge , I bring you medicine, I bring you nuclear technology, take
me to your leader"? Or, do we simply step on them? Any civilization capable
of reaching the planet Earth would be perhaps a Type III civilization. And
the difference between you and the ant is comparable to the distance between
you and a Type III civilization. Therefore, for the most part, a Type III
civilization would operate with a completely different agenda and message
than our civilization.
Let's say that a ten-lane superhighway is being built next to the anthill.
The question is: would the ants even know what a ten-lane superhighway is,
or what it's used for, or how to communicate with the workers who are just
feet away? And the answer is no. One question that we sometimes ask is if
there is a Type III civilization in our backyard, in the Milky Way galaxy ,
would we even know its presence? And if you think about it, you realize that
there's a good chance that we, like ants in an anthill, would not understand
or be able to make sense of a ten-lane superhighway next door.
So this means there that could very well be a Type III civilization in our
galaxy, it just means that we're not smart enough to find one. Now, a Type
III civilization is not going to make contact by sending Captain Kirk on the
Enterprise to meet our leader. A Type III civilization would send
self-replicating Von Neumann probes to colonize the galaxy with robots. For
example, consider a virus. A virus only consists of thousands of atoms. It's
a molecule in some sense. But in about one week, it can colonize an entire
human being made of trillions of cells. How is that possible?
Well, a Von Neumann probe would be a self-replicating robot that lands on a
moon; a moon, because they are stable, with no erosion, and they're stable
for billions of years. The probe would then make carbon copies of itself by
the millions. It would create a factory to build copies of itself. And then
these probes would then rocket to other nearby star systems, land on moons,
to create a million more copies by building a factory on that moon.
Eventually, there would be sphere surrounding the mother planet , expanding
at near-light velocity , containing trillions of these Von Neumann probes,
and that is perhaps the most efficient way to colonize the galaxy. This
means that perhaps, on our moon there is a Von Neumann probe, left over from
a visitation that took place million of years ago, and the probe is simply
waiting for us to make the transition from Type 0 to Type I.
Yes. This, of course, is the basis of the movie 2001, because at the
beginning of the movie, Kubrick interviewed many prominent scientists, and
asked them the question, "What is the most likely way that an advanced
civilization would probe the universe?" And that is, of course, through
self-replicating Von Neumann probes, which create moon bases. That is the
basis of the movie 2001, where the probe simply waits for us to become
interesting. If we're Type 0, we're not very interesting. We have all the
savagery and all the suicidal tendencies of fundamentalism, nationalism,
sectarianism, that are sufficient to rip apart our world.
By the time we've become Type I, we've become interesting, we've become
planetary, we begin to resolve our differences. We have centuries in which
to exist on a single planet to create a paradise on Earth, a paradise of
knowledge and prosperity.