Hans Moravec


Exploration and colonization of the universe awaits, but earth-adapted
biological humans are ill-equipped to respond to the challenge.
Machines have gone farther and seen more, limited though they
presently are by insect-like behavioral inflexibility. As they become
smarter over the coming decades, space will be theirs. Organizations
of robots of ever increasing intelligence and sensory and motor
ability will expand and transform what they occupy, working with
matter, space and time. As they grow, a smaller and smaller fraction
of their territory will be undeveloped frontier. Competitive success
will depend more and more on using already available matter and space
in ever more refined and useful forms. The process, analogous to the
miniaturization that makes today’s computers a trillion times more
powerful than the mechanical calculators of the past, will gradually
transform all activity from grossly physical homesteading of raw
nature, to minimum-energy quantum transactions of computation. The
final frontier will be urbanized, ultimately into an arena where every
bit of activity is a meaningful computation: the inhabited portion of
the universe will transformed into a cyberspace.

Because it will use resources more efficiently, a mature cyberspace of
the distant future will be effectively much bigger than the
present physical universe. While only an infinitesimal fraction of
existing matter and space is doing interesting work, in a well
developed cyberspace every bit will be part of a relevant computation
or storing a useful datum. Over time, more compact and faster ways of
using space and matter will be invented, and used to restructure the
cyberspace, effectively increasing the amount of computational
spacetime per unit of physical spacetime.

Computational speedups will affect the subjective experience of
entities in the cyberspace in a paradoxical way. At first glimpse,
there is no subjective effect, because everything, inside and outside
the individual, speeds up equally. But, more subtly, speedup produces
an expansion of the cyber universe, because, as thought accelerates,
more subjective time passes during the fixed (probably
lightspeed) physical transit time of a message between a given
pair of locations – so those fixed locations seem to grow farther
apart. Also, as information storage is made continually more
efficient through both denser utilization of matter and more efficient
encodings, there will be increasingly more cyber-stuff between any two
points. The effect may somewhat resemble the continuous-creation
process in the old steady-state theory of the physical universe of
Hoyle, Bondi and Gold, where hydrogen atoms appear just fast enough
throughout the expanding cosmos to maintain a constant

A quantum-mechanical entropy calculation by Bekenstein suggests that
the ultimate amount of information that can be stored given the mass
and volume of a hydrogen atom is about a megabyte. But let’s be
conservative, and imagine that at some point in the future only
“conventional” physics is in play, but every few atoms stores a useful
bit. There are about 1056 atoms in the solar system. I
estimate that a human brain-equivalent can be encoded in less than
1015 bits. If a body and surrounding environment takes a
thousand times more storage in addition, a human, with immediate
environment, might consume 1018 bits. An AI with
equivalent intelligence could probably get by with less, since it does
without the body-simulation “life support” needed to keep a
body-oriented human mind sane. So a city of a million human-scale
inhabitants might be efficiently stored in 1024 bits. If
the atoms of the solar system were cleverly rearranged so every 100
could represent a bit, then a single solar system could hold
1030 cities – far more than the number (1022) of
stars in the visible universe! Multiply that by
1011 stars in a galaxy, and one gets 1041 cities
per galaxy. The visible universe, with 1011 galaxies,
would then have room for 1051 cities – except that by the
time intelligence has expanded that far, more efficient ways of using
spacetime and encoding data would surely have been discovered,
increasing the number much further.

Mind without Body?

Start with the concepts of telepresence and virtual reality. You wear
a harness that, with optical, acoustical, mechanical and chemical
devices controls all that you sense, and measures all of your actions.
Its machinery presents pictures to your eyes, sounds to your ears,
pressures and temperatures to your skin, forces to your muscles and
even smells and tastes for the remaining senses. Telepresence results
when the inputs and outputs of this harness connect to a distant
machine that looks like a humanoid robot. The images from the robot’s
two camera eyes appear on your “eyeglass” viewscreens, and you hear
through its ears, feel through its skin and smell through its chemical
sensors. When you move your head or body, the robot moves in exact
synchrony. When you reach for an object seen in the viewscreens, the
robot reaches for the object, and when it makes contact, your muscles
and skin feel the resulting weight, shape, texture and temperature.
For most practical purposes you inhabit the robot’s body – your sense
of consciousness has migrated to the robot’s location, in a true “out
of body” experience.

Virtual reality retains the harness, but replaces the remote robot
with a computer simulation of a body and its surroundings. When
connected to a virtual reality, the location you seem to inhabit does
not exist in the usual physical sense, rather you are in a kind of
computer-generated dream. If the computer has access to data from the
outside world, the simulation may contain some “real” items, for
instance representations of other people connected via their own
harnesses, or even views of the outside world, perhaps through
simulated windows.

One might imagine a hybrid system where a virtual “central station” is
surrounded by portals that open on to views of multiple real
locations. While in the station one inhabits a simulated body, but
when one steps through a portal, the harness link is seamlessly
switched from the simulation to a telepresence robot waiting at that

The technical challenges limit the availability, “fidelity” and
affordability of telepresence and virtual reality systems today – in
fact, they exist only in a few highly experimental demonstrations.
But progress is being made, and its possible to anticipate a time, a
few decades hence, when people spend more time in remote and virtual
realities than in their immediate surroundings, just as today most of
us spend more time in artificial indoor surroundings than in the great
outdoors. The remote bodies we will inhabit can be stronger, faster
and have better senses than our “home” body. In fact, as our home
body ages and weakens, we might compensate by turning up some kind of
“volume control.” Eventually, we might wish to bypass our atrophied
muscles and dimmed senses altogether, if neurobiology learns enough to
connect our sensory and motor nerves directly to electronic
interfaces. Then all the harness hardware could be discarded as
obsolete, along with our sense organs and muscles, and indeed most of
our body. There would be no “home” experiences to return to, but our
remote and virtual existences would be better than ever.

The picture is that we are now is a “brain in a vat,” sustained by
life-support machinery, and connected by wonderful electronic links,
at will, to a series of “rented” artificial bodies at remote
locations, or to simulated bodies in artificial realities. But the
brain is a biological machine not designed to function forever, even
in an optimal physical environment. As it begins to malfunction,
might we not choose to use the same advanced neurological electronics
that make possible our links to the external world, to replace the
gray matter as it begins to fail? Bit by bit our brain is replaced by
electronic equivalents, which work at least as well, leaving our
personality and thoughts clearer than ever. Eventually everything has
been replaced by manufactured parts. No vestige of our original body
remains, but our thoughts and awareness continue. We will call this
process, and other approaches with the same end result, the
downloading of a human mind into a machine. After downloading,
our personality is a pattern impressed on electronic hardware, and we
may then find ways to move our minds to other similar hardware, just
as a computer program and its data can be copied from processor to
processor. So not only can our sense of awareness shift from place to
place at the speed of communication, but the very components of our
minds may ride on the same data channels. We might find ourselves
distributed over many locations, one piece of our mind here, another
piece there, and our sense of awareness at yet another place. Time
becomes more flexible – when our mind resides in very fast hardware,
one second of real time may provide a subjective year of thinking
time, while a thousand years of real time spent on a passive storage
medium may seem like no time at all. Can we then consider ourselves
to be a mind without a body? Not quite.

A human totally deprived of bodily senses does not do well. After
twelve hours in a sensory deprivation tank (where one floats in a
body-temperature saline solution that produces almost no skin
sensation, in total darkness and silence, with taste and smell and the
sensations of breathing minimized) a subject will begin to
hallucinate, as the mind, somewhat like a television tuned to a
nonexistent channel, turns up the amplification, desperately looking
for a signal, becoming ever less discriminating in the theories it
offers to make sense of the random sensory hiss it receives. Even the
most extreme telepresence and virtual reality scenarios we have
presented avoid complete bodylessness by always providing the mind
with a consistent sensory (and motor) image, obtained from an actual
remote robot body, or from a computer simulation. In those scenarios,
a person may sometimes exist without a physical body, but never
without the illusion of having one.

But in our computers there are already many entities that resemble
truly bodiless minds. A typical computer chess program knows nothing
about physical chess pieces or chessboards, or about the staring eyes
of its opponent or the bright lights of a tournament. Nor does it
work with an internal simulation of those physical attributes. It
reasons instead with a very efficient and compact mathematical
representation of chess positions and moves. For the benefit of human
players this internal representation is sometimes translated to a
recognizable graphic on a computer screen, but such images mean
nothing to the program that actually chooses the chess moves. For all
practical purposes, the chess program’s thoughts and sensations – its
consciousness – is pure chess, with no taint of the physical, or any
other, world. Much more than a human mind with a simulated body
stored in a computer, a chess program is a mind without a

So now, imagine a future world where programs that do chess,
mathematics, physics, engineering, art, business or whatever, have
grown up to become at least as clever as the human mind. Imagine also
the most of the inhabited universe has been converted to a computer
network – a cyberspace – where such programs live, side by side with
downloaded human minds and accompanying simulated human bodies.
Suppose that all these entities make their living in something of a
free market way, trading the products of their labor for the
essentials of life – in this world memory space and computing cycles.
Some entities do the equivalent of manual work, converting undeveloped
parts of the universe into cyberspace, or improving the performance of
existing patches, thus creating new wealth. Others work on physics or
engineering problems whose solutions give the developers new and
better ways to construct computing capacity. Some create programs
that can become part of one’s mental capacity. They trade their
discoveries and inventions for more working space and time. There are
entities that specialize as agents, collecting commissions in return
for locating opportunities and negotiating deals for their clients.
Others act as banks, storing and redistributing resources, buying and
selling computing space, time and information. Some we might class as
artists, creating structures that don’t obviously result in physical
resources, but which, for idiosyncratic reasons, are deemed valuable
by some customers, and are traded at prices that fluctuate for
subjective reasons. Some entities in the cyberworld will fail to
produce enough value to support their requirements for
existence – these eventually shrink and disappear, or merge with other
ventures. Others will succeed and grow. The closest present day
parallel is the growth, evolution, fragmentation and consolidation of
corporations, whose options are shaped primarily by their economic

A human would likely fare poorly in such a cyberspace. Unlike the
streamlined artificial intelligences that zip about, making
discoveries and deals, reconfiguring themselves to efficiently handle
the data that constitutes their interactions, a human mind would
lumber about in a massively inappropriate body simulation, analogous
to someone in a deep diving suit plodding along among a troupe of
acrobatic dolphins. Every interaction with the data world would first
have to be analogized as some recognizable quasi-physical entity:
other programs might be presented as animals, plants or demons, data
items as books or treasure chests, accounting entries as coins or
gold. Maintaining such fictions increases the cost of doing business,
as does operating the mind machinery that reduces the physical
simulations into mental abstractions in the downloaded human mind.
Though a few humans may find a niche exploiting their baroque
construction to produce human-flavored art, more may feel a great
economic incentive to streamline their interface to the

The streamlining could begin with the elimination of the
body-simulation along with the portions of the downloaded mind
dedicated to interpreting sense-data. These would be and replaced
with simpler integrated programs that produced approximately the same
net effect in one’s consciousness. One would still view the cyber
world in terms of location, color, smell, faces, and so on, but only
those details we actually notice would be represented. We would still
be at a disadvantage compared with the true artificial intelligences,
who interact with the cyberspace in ways optimized for their tasks.
We might then be tempted to replace some of our innermost mental
processes with more cyberspace-appropriate programs purchased from the
AIs, and so, bit by bit, transform ourselves into something much like
them. Ultimately our thinking procedures could be totally liberated
from any traces of our original body, indeed of any body. But the
bodiless mind that results, wonderful though it may be in its clarity
of thought and breadth of understanding, could in no sense be
considered any longer human.

So, one way or another, the immensities of cyberspace will be teeming
with very unhuman disembodied superminds, engaged in affairs of the
future that are to human concerns as ours are to those of bacteria.
But, once in a long while, humans do think of bacteria, even
particular individual bacteria seen in particular microscopes.
Similarly, a cyberbeing may occasionally bring to mind a human event
of the distant past. If a sufficiently powerful mind makes a
sufficiently large effort, such recall could occur with great
detail – call it high fidelity. With enough fidelity, the situation of
a remembered person, along with all the minutiae of body, thoughts,
and feelings would be perfectly recreated in a kind of mental
simulation: a cyberspace within a cyberspace where the person would be
as alive there as anywhere. Sometimes the recall might be
historically accurate, in other circumstances it could be artistically
enhanced: it depends on the purposes of the cybermind. An evolving
cyberspace becomes effectively ever more capacious and long lasting,
and so can support ever more minds of ever greater power. If these
minds spend only an infinitesimal fraction of their energy
contemplating the human past, their sheer power should ensure that
eventually our entire history is replayed many times in many places,
and in many variations. The very moment we are now experiencing may
actually be (almost certainly is) such a distributed mental event, and
most likely is a complete fabrication that never happened physically.
Alas, there is no way to sort it out from our perspective: we can only
wallow in the scenery.

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