I, Nanobot: The coming elimination of the barrier between living and nonliving

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I, Nanobot

by Alan H Goldstein

 

The coming elimination of the barrier between living and nonliving

materials will lead to " animats " (living materials) --

nanobiotechnology devices that can survive and function inside human

beings, derive energy from biological metabolism, and copy themselves

by molecular self-assembly. When that moment happens, it very likely

may be beyond our control....

 

 

Originally published on Salon.com March 9, 2006. Reprinted with

permission on KurzweilAI.net July 7, 2006.

 

Don't call me Ishmael, for I am not a survivor. Don't call me

Cassandra either, since some might believe what I foretell. Perhaps I

am the final manifestation of the singularity ignited in Olduvi Gorge

a million and a half years ago. The flame that has grown to consume

our planet and send sparks into outer space. The singularity that

started as an ineffable, ineluctable pulse resonating through the

neural matrix of Homo habilis. A voice that said, You whoever you are,

You must sharpen that stone, pick up that bone, cross that line. A

voice of supreme paradox; one that simultaneously makes us uniquely

human, yet is itself not human. Nor is it the black extraterrestrial

monolith of Stanley Kubrick's imagining. Rather, it was always here.

Hard-wired into us at the atomic level—and we into it. A voice whose

physical manifestation, the tool, sang its song millions of years

before human beings walked the earth. This voice prophesied and then

enabled our coming. It will instruct us in our going. Or so I say,

while understanding too well that in the 21st century we are all jaded

and stultified with sensory overload. It's always the end of the world

as we know it—and we feel bored.

 

So why listen to the voice of one who is not Ishmael, not Cassandra,

not even Ralph Nader? Because I can tell you something that no one

else can. I can tell you the exact moment when Homo sapiens will cease

to exist. And I can tell you how the end will come. I can show you the

exact design of the device that will bring us down. I can reveal the

blueprint, provide the precise technical specifications. Long before

we can melt the polar ice caps, or denude the rain forests, or

colonize the moon, we will be gone. And we will not—definitely will

not—end with a bang or a whimper. The human race will go to its

extinction in a state of supreme exaltation, like an actor climbing

the stairs to accept an Academy Award. We will exit the stage of

existence thinking we are going to a spectacular party.

 

The usual suspects—those who have become known for predicting the

evolution of humans and their technology—just don't get it. Mainly

because they don't understand what the definition of " it " is. They

don't realize what evolution is. They have come to the problem from

artificial intelligence, or systems analysis, or mathematics, or

astronomy, or aerospace engineering. Folks like Ray Kurzweil, Bill Joy

and Eric Drexler have raised some alarms, but they are too dazzled by

the complexity and power of human cybersystems, devices and networks

to see it coming. They think the power of our tools lies in their

ever-increasing complexity—but they are wrong. The biotech folks just

don't get it either. People like Craig Venter and Leroy Hood are too

enthralled with the possibilities inherent in engineering biology to

get it. And our " bioethicists, " like Arthur Kaplan, and those who

cling to their human DNA like it was the Holy Grail or the original

tablets of stone, blathering on like Captain Kirk about what special,

sacred things we humans are—they can't possibly get it. All these

people who think (or fear) that technology will ultimately trump

biology have missed the cosmic point. They are not even wrong. To

begin to get it, one must dispense with artificial boundaries. If you

are only thinking about cybersystems and DNA you can't possibly get

it. And if you are thinking outside the box, you are still thinking

too much like a human being.

 

Linus Pauling would have gotten it right away. Erwin Schrödinger too,

and probably Robert Oppenheimer. Bertrand Russell got it. In fact he

named it. What Ray, and Craig, and Eric, and Arthur can't see is the

power of pure chemistry—what Bertrand Russell called " chemical

imperialism. " What they don't get is this— a system does not have to

be complex to be transcendently, transformatively powerful. After all,

we and everything we have created are nothing but the product of

" carbon imperialism " —carbon being the element that all known life is

based on. Nothing but the power of pure chemistry. Living and

nonliving materials, everything that exists in the physical world of

our experience burns with that same electron fire. The fire of the

chemical bond.

 

And Prometheus has returned. His new screen name is nanobiotechnology.

 

Quick. What's the difference between artificial life and synthetic

biology? Don't know? Neither does anyone else, but that isn't stopping

nanobiotechnology researchers from building them—or it, or that, or

whatever. To stay up to speed, there is always Artificial Life, the

official journal of the International Society of Artificial Life.

According to the editors, the humble mission of the journal " is [to

investigate] the scientific, engineering, philosophical, and social

issues involved in our rapidly increasing technological ability to

synthesize life-like behaviors from scratch in computers, machines,

molecules, and other alternative media. " Whoa!

 

The federal government is in the game big-time as well. For example,

the Physical Biosciences Division at Lawrence Berkeley National

Laboratory tells us it has established the world's first Synthetic

Biology Department, " to understand and design biological systems… "

 

Some people might argue that it is pretty cavalier to work on

" artificial life " or " synthetic biology " before we have even agreed on

definitions for these " things. " They might even point out that

" artificial life " containing nonbiological components or new forms of

biology could drastically alter the ecological balance or even the

evolutionary trajectory of life on Earth. Of course the Lawrence

Berkeley folks tell us we " need " synthetic biology for all kinds of

excellent reasons. We need it for the efficient conversion of waste

into energy and sunlight into hydrogen. We need it to create new life

forms to use as " soft " biomaterials for tissue/organ growth. We need

it to spawn new cells that will swim through the air or water to get

to chemical and biological threats and decontaminate them. We need it,

and we will build it, and it will be OK because we are the good guys

(and gals). Our new life forms will only do good things.

 

In fact, we are very dangerously confused. To understand how confused,

we must introduce the First Law of Nanobotics: The fusion of

nanotechnology and biotechnology, now called nanobiotechnology, will

result in the complete elimination of the barrier between living and

nonliving materials. In other words, nanobiotechnology not only has

the goal, it has the mandate to break through the " carbon barrier " of

life. The result: We will produce not mere cyborgs, but true hybrid

artificial life forms—or manifestations of synthetic biology, take

your pick. In a previous article on nanomedicine I described a few of

the rudimentary " things " that will emerge from nanobiotechnology:

molecular machines that contain parts from both the worlds of biology

and human engineering. Single-walled carbon nanotubes linked to DNA.

Gold nanoshells linked to antibody proteins.

 

But gold nanoshells linked to antibodies are just a simple prototype.

The fact is, we have no idea what artificial life and/or synthetic

biology is, much less what it could do, or how it will behave. A

recent article in Science provides terrifying evidence of our hubris.

Toward the end of this article, the author explains, " Ethical and

environmental concerns must also be dealt with before synthetic

biology fully matures as a field. MIT, the Venter Institute, and the

Center for Strategic and International Studies in Washington, D.C.,

have teamed up to examine issues such as how to keep any new life

forms created under control ... One solution: Alter synthetic genetic

codes such that they are incompatible with natural ones because there

is a mismatch in the gene's coding for amino acids. "

 

In other words, we will be protected because these organisms will have

genomes never before seen on Earth! Perhaps, but that could also be a

description of the ultimate biohazard. If the Ebola virus is

considered a Biosafety Level 4 threat, what level would categorize a

pathogenic organism made completely from synthetic genetic codes?

 

In order to understand the astonishing leap we are about to make, one

needs to grasp that nanobiotechnology is more than just another tool.

It is also a monumental experiment in molecular evolution over which

we may ultimately have very little control. A nanobiotechnology device

that is smart enough to circulate through the body hunting viruses or

cancer cells is, by definition, smart enough to exchange information

with that human body. This means, under the right conditions, the

" device " could evolve beyond its original function. Cancer-hunting

nanobots are often depicted as tiny robotic machines —thus

reassuringly impervious to fundamental changes brought on by merging

with their biological environment. But they will not be tiny robots.

That mechanical fantasy, promulgated by proponents of " Drexlerian "

nanotechnology who appear devoid of even the most rudimentary

knowledge of chemistry, has been decisively refuted by people who

actually build the components for nanobiotechnology systems. People

like the late Nobel Prize-winning chemist Richard E. Smalley and the

great Harvard bioorganic chemist George Whitesides.

 

What will really go into our bodies, or out into the environment, will

be hybrid molecular devices composed of both synthetic and biological

components. These " devices " will have been fabricated to specifically

exchange chemical information with biological or ecological systems.

They will not be nanobots, they will be nanobiobots—and those three

letters make all the difference.

 

In fact, the ability to exchange molecular information with biological

systems will be an absolute requirement for these devices to carry out

the functions for which they will be created. To find cancer cells, or

dissolve arterial plaque, or modify damaged neurological pathways,

nanobiobots will be required to " speak " the language of

biochemistry—our language, evolution's language. Yet they will not be

classifiable as the products of biological evolution, or genetic or

human engineering. They will be true hybrids. We cannot, must not,

assume that our current safety and testing standards, whether

chemical, biological or toxicological, will be sufficient to predict

the behavior of nanobiobots once they are released into the world.

 

The precautionary principle developed for environmental policy states

that " where there are threats of serious or irreversible damage to the

environment, lack of full scientific certainty should not be used as a

reason for postponing cost-effective measures to prevent environmental

degradation. " This is generally interpreted to mean that a lower level

of proof of harm can be used in policymaking whenever the consequences

of waiting for higher levels of proof may be very costly and/or

irreversible.

 

Given that we don't even have definitions for artificial life or

synthetic biology, how would we even begin to apply the precautionary

principle here? But we urgently need to.

 

Let's take a simple example. Plans are currently underway to create

medical nanobiobots that will use our own metabolic energy (for

example, glucose oxidation) as a source of power. That means these

devices could remain operational as long as we are alive—or longer if

they manage to get into human egg or sperm cells. Any nanobiobot that

develops the ability to propagate in this or any other manner across

even one human generation has fulfilled the definition of a

non-biological life form. A true alien. And it can happen.

 

Suppose a glucose-powered nanobiobot has been created to hunt cancer

cells via a component antibody moiety. In effect, this nanobiobot has

a protein grappling hook designed to dock it with a specific type of

tumor cell. Standard dosing therapy will require that billions of

these nanobiobots be released into their human " host. " If the antibody

arm on even one of these nanobiobots is modified (either by some type

of catalytic recombination with circulating antibodies or by simple

chemical damage) so that it binds to a different type of cell, it

could stay in that body for life, like cryptic viruses such as

Epstein-Barr. If this nanobiobot is modified so that it can attach to

a human sperm or egg cell, it could theoretically stay in the

population for generations.

 

If this type of nanobiotechnology-based cancer therapy becomes common

(and according to the NCI's nanomedicine site, that is a real

possibility), we could have tens of thousands of people carrying

cryptic nanobiobots. Even though these nanobiobots were designed for

different functions, it is reasonable to assume that they will have a

number of components in common. For example, many of them may have

antibody components that, in turn, have regions of identical protein

structure. These interchangeable parts could act just like the

repetitive DNA of introns in eukaryotic genomes. What happens when one

nanobiobot (say) on a sperm cell meets a second one on an egg cell?

The probability of this is, of course, extremely low. But if the

population of nanobiobots introduced into the body is high (say,

billions), then a one-in-a-million event becomes common. In fact,

microbial and viral systems like E. coli and bacteriophages enabled

the molecular genetics revolution precisely because with billions (or

even trillions) of test organisms in hand, one-in-a-million events

become commonplace.

 

Suppose in the near future, a routine nanomedical procedure involved

the introduction of billions of nanobiobots designed to scour the

arteries dissolving plaque. Cleaning out the circulatory system would

be considered a " one shot " treatment so that these therapeutic

nanomedical devices (nanobiobots) would not have the engine necessary

to use human metabolic energy as a power source. But what if, during

another " routine " nanomedical procedure, a second therapeutic

nanomedical device (nanobiobot) designed to vaccinate against cancer

is introduced into the same person? This latter nanobiobot would, by

definition, be designed for longevity so that metabolic energy would

likely be the power source. Now, what if these two meet up and

combine, or exhange vital components? This could happen through

physico-chemical damage or perhaps via some type of catalysis mediated

by the host's own complex biochemistry. Now we have a novel, hybrid

nanobiobot capable of crawling through our circulatory system for

life. Or until it exchanges even more information—either with another

nanobiobot or with the body itself. In the world of biology, this type

of event would be called a mutation.

 

Even more likely is the " prion " scenario, in which one of the billions

of nanobiobots in the body is damaged or modified and, as a result,

gains the ability to convert other nanobiobots in a manner that alters

longevity, tissue target, etc. (This is what the abnormally structured

proteins called prions do. Prions are responsible for fatal,

mysterious brain-tissue diseases like " mad cow " and fatal familial

insomnia.) These myriad possibilities bring us to...

 

The Second Law of Nanobotics: It is not possible to ensure that

devices created using the techniques of nanobiotechnology will only

transmit molecular information to the target system.

 

This law essentially says it is impossible to ensure that molecular

information only flows in one direction. Just as today's

pharmaceuticals almost always have side effects, there is no natural

law that guarantees against the reverse movement of fundamental

chemical information from the biosystem to the nanobiobot. Any real

nanobiotechnology system—one that uses a combination of biological and

synthetic components—is theoretically vulnerable to a reversal in the

flow of molecular information. This, in turn, will create

opportunities for the unpredictable evolutionary advances of these

devices via a process similar to biological mutation.

 

Put plainly, if the nanobiobot can modify us there is no way to ensure

that we can't modify the nanobiobot.

 

Corollary to the Second Law of Nanobotics: Before nanobiobots are used

outside of a controlled research laboratory environment, we must try

to define and understand what it is we are making. And rigorous

algorithms and adversary-analysis systems must be developed to test

these devices to ensure that they are not obviously vulnerable to the

reverse flow of molecular information. Of course, we will never know

this with certainty. But we haven't even started trying to find out.

 

What this all means is that within a generation, biology will face its

ultimate identity crisis. Researchers in the field of

nanobiotechnology are racing to achieve the complete molecular

integration of living and nonliving materials. We will hack into the

CPU of life in order to insert new hardware and software. The purpose

is to extend the capabilities of biology far beyond the limits imposed

by evolution, to integrate the incredible biochemistry of life with

the equally spectacular chemistry of nonliving systems like

semiconductors and fiber optics. The idea is to hard-wire biology

directly into any and every part of the nonliving world where it would

be to our benefit. Optoelectronic splices for the vision impaired,

micromechanical valves to restore heart function.

 

But the moment we close that nano-switch and allow electron current to

flow between living and nonliving matter, we open the nano-door to new

forms of living chemistry—shattering the " carbon barrier. "

 

This is, without doubt, the most momentous scientific development

since the invention of nuclear weapons. When we open the door and

allow new forms of chemistry to enter, we will change the very

definition of life. Yet no coherent strategy exists to identify the

moment when nanoengineered smart materials cross over into the realm

of living materials. Could we even recognize a noncarbon life form at

the moment of its creation? The answer seems intuitively obvious until

we remember that we too are made of materials. That we too are machines.

 

Humans operate entirely on electric current. There are 10 trillion

living cells in your body, each powered by an electrical potential of

12,000,000 volts per meter. A thousand times as hot as the plug on

your wall. The voltage of life is produced inside every cell by a

sophisticated electrochemical power generator. Each subcellular

" mitochondrion " is a protein nanomachine designed by evolution to burn

sugar, one molecule at a time. The heat from this controlled burn

yields high-energy electrons that are the anima of the living state.

Every move you make can be traced back to a specific flicker of this

electron fire. Electromechanical systems drive the contraction of your

heart. Electro-optical systems capture the image on your retina.

Layers of electrochemical switches form the architecture of the neural

CPU in your brain.

 

The bioenergetic transformations that fuel life are an amazing

sequence of reactions that convert light into chemical bond energy.

The biological ecosystem of Earth is one gigantic solar-powered fuel

cell. Plants harvest the sun and animals harvest the plants. The first

step is the light-driven fusion of water and carbon dioxide into sugar

via the photosynthetic organisms—green plants and some microbes. This

sugar is the fuel that drives the chemical engine of animal life. Our

mitochondria use bio-catalytic converters to strip electrons from

sugar and feed them into your cellular power grid. As electrons move

between energy levels, current flows.

 

Electronic conduction thus provides the true interface between living

and nonliving materials. Today's technology does not allow fabrication

of components that plug directly into this interface, but we are

getting close. In the early 21st century, nanotechnology will create

the tools to hard-wire into the CPU of life, while biotechnology will

provide a complementary molecular schematic of our living circuits. It

is the engineering destiny of nanobiotechnology to create the first

electro-molecular interface between the living and nonliving worlds.

Or, more correctly, the first interface that does not discriminate

between the living and nonliving states of matter. Fabrication of the

world's first true Biomolecule-to-Material interface will be

infinitely more than a landmark in the evolution of human technology.

Like the separate days of Genesis, the first nanofabricated BTM

interface will be its own monumental act of creation and a crucial

step on the path to bona fide living materials, aka artificial life.

 

In the history of science, the conduction of signals between living

and nonliving materials will be divided into the pre-nanotech and

nanotech eras. We are still pre-nanotech, which means that a direct

BTM interface has yet to be fabricated, although bioengineering has

created synthetic devices that communicate indirectly with living

materials. Take an artificial pacemaker. This device transmits an

electrical voltage to the biological pacemaker cells of the heart. In

a healthy human, these pacemaker cells generate their own action

potential, an electrical waveform of about 100 millivolts. This may

not sound like much energy until we remember that this electrical

potential is sustained across an insulating membrane only five

nanometers thick. That is 5 billionths of a meter. So the energy of an

action potential is almost 20,000,000 volts per meter. Compare this to

the 12,000 volts per meter at a standard wall plug. Healthy pacemaker

cells spark the electrical wave that drives heart muscle contraction.

When these cells malfunction, an artificial pacemaker may be implanted

to take over. Waves of electrical voltage generated at the metal lead

of the artificial device cross over to living tissue and initiate

normal muscle contraction.

 

While the pacemaker is a magnificent feat of bioengineering, it does

not operate via a true BTM interface. The metal lead of the artificial

pacemaker, a small wire, is physically embedded in cardiac tissue and

the wave of voltage spreads from the charged tip into the surrounding

region. Only pacemaker cells will respond to the artificial voltage

wave by initiating a further action potential. So the living system

must identify the artificial signal and act upon it. The voltage

produced by an implanted pacemaker, like a radio signal, will pass

through space unnoticed unless there is an antenna to pick it up. In

this case the receiving antennae are individual protein molecules

embedded in the membrane of the living cardiac pacemaker cell. Other

heart cells feel the electrical signal, but do not respond to it. They

may be considered as nonspecific noise in the system. We must flood

the local tissue with electricity in order to obtain the desired response.

 

This strategy is extremely effective, but it does not constitute a

direct interface between living and nonliving materials. In the end,

the pacemaker does not " know " that the target cells are out there. It

will send its signal regardless of whether it is received or not.

Likewise, the cardiac pacemaker cells do not " know " that the charged

metal lead is out there; they simply respond to an electrical shock.

 

By contrast, a nanofabricated pacemaker with a true BTM interface will

feed electrons from an implanted nanoscale device directly into

electron-conducting biomolecules that are naturally embedded in the

membrane of the pacemaker cells. There will be no noise across this

type of interface. Electrons will only flow if the living and

nonliving materials are hard-wired together. In this sense, the system

can be said to have functional self-awareness: Each side of the BTM

interface has an operational knowledge of the other.

 

Molecular imprinting offers one nanotechnology strategy to build a BTM

switch in the near future. A molecular imprint works exactly the way

one would think. An isolated biomolecule is surrounded by some type of

self-reactive liquified matrix, often an unpolymerized plastic like

acrylamide. A cross-linking reagent is added, and a polymer forms

around the biomolecule. When the biomolecule is removed, its ghostly

outline is etched into a surface of solid plastic. The imprint fits

the biological surface with atomic precision so this nanoengineered

component is now a socket into which any identical biomolecule can be

plugged. In the case of a pacemaker, the voltage-sensitive protein

switches from cardiac cells would be imprinted into an electronic

material. The imprinted material would be nanomachined and joined to

an equally small power generator. The entire nanodevice, except for

the imprinted socket, is then coated with a biomimetic ultrathin film.

This coating makes the surface compatible with heart tissue. This

nanopacemaker will occupy less than 1 cubic micrometer, smaller than a

single bacterium. To complete the BTM interface, a living cardiac

pacemaker cell is excised from the patient and plugged into the socket

created by the original molecular imprint process. This can be

accomplished with a micromanipulator similar to those currently used

to move living nuclei in and out of cells. The " hard-wired "

nanopacemaker is implanted into the heart where it is cemented into

place by the body's normal healing process.

 

The example above was selected because it is relatively simple, using

technology that is already in the pipeline. Far more sophisticated

strategies are on the horizon. One involves literally drawing the

imprinted surface around the biomolecule by polymerizing monomers with

a computer-targeted laser. When bioengineers begin to fabricate these

BTM interfaces we will have entered the nanobiotech era.

 

If we continue to insist that life on Earth can only result from

biological evolution, then the first BTM interfaces built by

nanobiotechnology will be speciously trivialized as just a great

invention of Homo sapiens. We will congratulate ourselves and conclude

that the supremely gifted toolmaker has built the first portal between

the worlds of living and nonliving materials. This simplistic view of

nanobiotechnology is very much like humanity's current strategy in the

search for extraterrestrial life. In a chemically diverse universe we

insist on a perversely self-congratulatory strategy. Water and organic

molecules, such as methane, are the identified spoor on this trail. We

look for these signs because the biology-centric assumption is that

aliens will be just like us, only very, very different—little green

people with acid for blood, sentient jellyfish with a taste for

cheeseburgers, or insects that have evolved with a sense of humor.

Even search strategies that use " universal mathematical constants "

ignore the possibility, proposed by some postmodern philosophers of

science, that formal modern mathematics is a function of cognitive

structure unique to humans, or less specifically to a narrow range of

beings similar to humans, for example, hominids. The point is that

technology analysts who can only see life as some variation on biology

will see the BTM interface as a way for " us " to plug into " it. " Within

this paradigm there are no consequences for the definition of life,

only new enhancements for the one true life form: biology. We hold up

the mirror of humanity and see our own image reflected in the universe.

 

Most dictionaries define biology as " the science of living things. "

But the (correctly) limitless nature of that definition is truncated

when plants and animals are immediately used as the prime examples.

NASA, an agency that should know better, has saturated the media for

decades with hypnotic invocations of water and organics as the true

signs of extraterrestrial life. Meanwhile, Hollywood and pop culture

endlessly anthropomorphize aliens. Robots get the blues. Silicon

sentience springs directly from human mythology. Stories of demonic

computers and undead cyber-blood lust are endlessly refilmed with

really cool graphics, a variety of soundtracks, and excellent eyewear.

Skynet, the " self-aware " computer system of the " Terminator " series,

hates us and wants us dead. The equally demonic cyber-beings of " The

Matrix " want to enslave us and eat our energy (making this computer

both physically dangerous and dangerously ignorant of the physical

laws of the universe). It is distinctly ironic that when we consider

aliens, life on Earth infuses our scientific models, our dreams, and

our entertainment. We could call this " the biology paradox. " The

biology paradox makes xenobiology speciously comprehensible, but by

clinging to it we dismiss almost all of the chemistry in the universe.

 

It is time for serious students of sentience to accept that common

usage has rendered the term " biology " completely useless in the

nanotech age. Thinking outside the biology box leads to the

alternative, much more radical concept of living materials—materials

with anima.

 

To describe this new state of life, I suggest a contraction of the

term " anima-materials " — " animats. " This term has previously been used

to describe adaptive or cognitive systems capable of robust action in

a dynamic environment. The goal of these systems involves the creation

of higher levels of cognition from many smaller processes. Many

scientists who work in this field appear ready to dismiss chemical

sentience as smaller and simpler than anything they would consider

smart. But we must not assume that minds are built from mindless

stuff. Chemical intelligence can manifest as the ability to catalyze a

single chemical reaction. It is a dangerous, and possibly terminal,

error for the children of carbon to dismiss the power of pure electron

fire. Much of our fear of bioterror is based on the power (chemical

intelligence) of a single molecule that allows it to block a single

metabolic reaction inside the human body.

 

Better to heed Bertrand Russell's prescient warning that " Every living

thing is a sort of imperialist, seeking to transform as much as

possible of its environment into itself. " Russell goes on to use the

term " chemical imperialism " as the driving force for biological life.

The obvious corollary to this warning is that chemical imperialism

spawned human intelligence, not the other way around. Therefore, the

definition of an animat as a living material should have primacy over

any definition involving more complex cognitive functions. If we

accept this logic, the creation of the first BTM interface by

nanobiotechnology will require a new operational definition for the

living state.

 

To expand the chemical franchise of the living state we must first

deconstruct biology. The Human Genome Project sold us the concept that

DNA is the chemical basis of life. But, in fact, that is not true. DNA

is the result of life, not its cause. Our genetic code is the crowning

achievement of biochemistry, not its progenitor.

 

It is crucial to keep this distinction in mind when considering the

concept of animats. Life is not defined by DNA but by a continuous

chemical struggle against entropy. The second law of thermodynamics

tells us that all natural systems move spontaneously toward maximum

entropy. By literally assembling itself from thin air, biological life

appears to be the lone exception to this law. The gaseous molecules

snared by plants during photosynthesis were once free to roam the

entire atmosphere of Earth. Plants—Earth's primary producers —fix gas

molecules from the air and minerals from the water into sugars and

proteins. Humans eat the plants, or we eat the animals that eat the

plants. Now those molecules that were free to roam the skies and

waters must be where you are, go where you go, and do what you do.

Clearly, the atoms in your body have experienced a radical reduction

in entropy. But thermodynamics takes the full measure of the physical

world. What little biology can build is barely visible against the

chaotic horizon generated as the sun exfoliates into space. Like a

tiny windmill in the solar hurricane, the wheel of life is turned by a

unique set of chemical reactions that capture and channel the least

part of that storm of dissipating energy into further cycles of

replication. Biological life is a tiny stowaway on the entropy-powered

craft of our solar system.

 

Life, then, is not based on DNA but on a chemical programming language

spoken by a discrete set of biomolecules. This language directs the

set of operations necessary to assemble the next generation of

biomolecules. DNA or RNA, the genetic material, stores the directory

of available biochemical operations but does not execute them. The

program steps for replication are executed by a set of protein

catalysts collectively known as enzymes. It is probable that the first

biological life forms were RNA molecules capable of both catalytic

replication and data storage—so-called ribozymes. Through evolutionary

time, RNA generated two biochemical subroutines, proteins and DNA, to

carry out some of the operations of replication and data storage with

greater efficiency. Yet a cursory look at the molecular biology of the

cell proves that RNA retains its central role. If life is viewed as a

discrete set of chemical operations, then nanofabricated components

that directly interface biological and materials chemistry must create

the possibility of new life forms. These nanofabricated components

are, in fact, the next generation of self-replicating systems: not

enzymes but animats.

 

One could argue that it is too early to be talking about animats. It

is easy, and reassuring, to dismiss even the most advanced

nanobiotechnology systems of the near future as mere devices. But if

biological evolution is any guide, that viewpoint is both specious and

potentially catastrophic. During the 3-billion-year operation of the

algorithm called evolution, revolutionary new adaptations often began

as trivial events. A small genetic mutation resulting in a slightly

altered protein that provides an incremental, almost trivial,

enhancement to catalytic function.

 

Thermal tolerance is a classic example. A mutation to the DNA sequence

translates into a modified physical structure for an essential

protein. This new structure has enhanced thermal stability, which

means it retains enzymatic function at a higher temperature than the

original. As a result, the mutant is capable of 100 percent catalytic

efficiency in climates a few degrees hotter than normal. This change

in protein structure will only involve the rearrangement of a few

atoms, making molecular evolution the original nanoengineer.

 

Over time, the heat-tolerant progeny of the original mutant may be

able to migrate into a warmer climate: say, move down the Sierra

Nevada into Death Valley. But it takes thousands of reproductive

generations or more for this migration to actually occur. The original

mutation will not become essential for a hundred thousand, or even

millions of years. Evolution covers enormous distances one angstrom at

a time, which means it is almost impossible to catch an adaptation at

the exact moment, or even in the exact generation, that it becomes

essential for survival. Likewise, it is highly probable that the BTM

interface will evolve from smart material to living material. This

means that, in order to find the moment when the first animat appeared

on Earth, we will have to backtrack from the future. Or be watching

the present very, very carefully.

 

Based on this evolutionary model, it is highly unlikely that animats

will spring fully grown upon the Earth. It is much more likely that

animats will initially evolve as part of a larger biological system.

In order to identify the first true manifestation of a living

nonbiological material, we must develop a definitive test to

distinguish an organism that is at least part animat from one that

carries a smart material designed simply to assist or enhance life

function.

 

This brings us to the Third Law of Nanobotics: The carbon barrier will

be eliminated when humans create the first synthetic molecular device

capable of changing the state of a living system via direct,

intentional transfer of specific chemical information from one to the

other.

 

This law formalizes the concept of animats and leads directly to the

" Animat Test, " which is designed to identify the moment in time when

life on Earth evolves to include both biological and nonbiological

materials—the date when we break the carbon barrier.

 

Let us define a life form as an entity that reduces entropy by

self-executing the minimum set of physical and chemical operations

necessary to sustain the ability to execute functionally equivalent

negentropic operations indefinitely across time. Given that, a life

form will be considered an animat (living material) if all the

information necessary to execute that minimum set of physical and

chemical operations cannot be stored in DNA or RNA. The corollary: If

all the information necessary to execute that minimum set of physical

and chemical operations can be stored in DNA or RNA, the life form is

biological.

 

In the beginning, nanobiotechnology will create minute supplemental

lifesaving medical devices for humans. The purpose of these devices

will rapidly expand to include the performance-enhancing—an inexorable

development I have discussed previously. Some of these things will

remain devices. But some will have the potential to evolve and should

be termed proto-animats. The animat test is designed to be a practical

engineering tool to identify the point in time when the proto-animat

crosses over and becomes a true living material, an animat. The

conditions of the test are independent of both the physical structure

of the life form and the physical modality by which the life form

perpetuates a negentropic existence across time. That modality could

include replication, and/or duplication, and/or continuous

self-restoration. The test cannot be applied to entropic life forms

since human understanding of physical laws does not currently allow

discrimination between life forms and other natural phenomena without

cycles of entropy reduction.

 

Much as we track incoming comets on a possible collision course with

Earth, extraordinary vigilance is required as we transition into the

age of nanobiotechnology. If the evolutionary model prevails, we are

seeking to identify proto-animats: smart materials potentially capable

of evolving into animats, living materials. This, in turn, will

require a radical expansion of our thinking with respect to the

potential sources of artificial life. Up till now (and thanks to

people like Ray, Bill and Eric), most models have focused on computers

and machine intelligence. Smart materials can certainly contain

computers. But it is unlikely that animats will spring to life via

some Hollywood scenario whereby a supercomputer crashes into A.I.

self-awareness and begins photovoltaic-powered reproductive assembly

of little A.I.s (subsequent end-of-the-human-world-as-we-know-it

scenarios optional, heavy metal sound track preferred). If the

evolutionary algorithm is any guide, animats will break the carbon

barrier the way the Bell X-1 broke the sound barrier, carried aloft on

the wings of a mother ship. The mother ship will be named Homo

sapiens. The initial manifestation of an animat life form will be

evolutionary in form, but revolutionary in function. There is also the

possibility of progression from the ternary fusion of biological life,

machine intelligence, and smart materials (proto-animats). But it is

crucial to recognize that living materials need only think with their

chemistry. No Boolean or humanoid logic is required to qualify as

life. The absolute progress of chemical imperialism can only be

measured in entropy reduction.

 

Unless we know what we are looking for, the first proto-animats will

be invisible in the storm of nanobioengineering systems expected to

come online over the next generation of human life. Most of these

nanodevices will not have the potential to evolve beyond cyborg mode,

i.e., technical augmentations to biological life forms. There are many

future scenarios in which humans will need their machines to continue

to live, but until an animat is carried through time as part of a life

form's self-executing set of essential operations, the carbon barrier

will remain intact. But when the portal between two worlds is

atom-size, how will we know when it finally opens?

 

In a world where we are already doing research on artificial life,

synthetic biology and nanobiotechnology, this question cannot possibly

be considered academic. Materials will continue to get smarter until

they finally break the carbon barrier. In the near future, some

nanoscale cyborg technology will undoubtedly be designed to propagate

along with the host using molecular self-assembly, the same strategy

used by biological systems.

 

But self-assembly is not unique to living systems and, therefore,

cannot be used as the litmus test for new forms of life. Water

molecules can self-assemble into the simple crystalline pattern of an

ice cube or the infinite complexity of a snowflake. Quartz and other

inorganic minerals can spontaneously crystallize and grow with a

concomitant reduction in entropy, yet geodes are definitely not alive.

 

However, molecular self-assembly is an excellent strategy for building

nanomachines and many researchers are studying ways to harness this

phenomenon. Such nanomachines could even be designed to use

self-assembly to replicate. The original " Grey Goo " scare (the very

mention of which is anathema to most nanoscientists) involved a

scenario whereby endlessly self-replicating nanomachines literally

covered the earth. This scenario is generally attributed to

speculation contained in Eric Drexler's 1986 book " Engines of Creation. "

 

While the science behind the original Grey Goo scare was and remains

completely unrealistic, we are getting better and better at using

molecular self-assembly to build, maintain and propagate nanomachines.

For example, it is certainly realistic to posit nanomachines that use

ingested trace metals and semiconductor nanoparticles (for example,

silica) to replicate inside the host's cells, including germ cells.

This type of device could enhance human performance and even move from

parent to child, yet would not be considered to be a new life form

(either alone or in combination with its human host) unless it could

pass the animat test. More to the point, the animat test gives us a

way to determine when a smart material crosses over and becomes a life

form.

 

It is ironic that, because of nanobiotechnology, we have never been

closer to a Grey Goo scenario—although the actual color will more

likely be green or red. Because biomolecules learned self-assembly

through billions of years of evolution, nanobiotechnology has a

tremendous advantage when it comes to applying this particular

strategy to create artificial life.

 

In fact, we have put into motion research that will create every

component necessary to build an animat. One formula is as simple as A

+ B + C.

 

A = Nanobiotechnology devices that can survive and function inside

human beings. Many therapeutic devices in development for drug

delivery, cancer therapy, etc., are designed to survive in the

physicochemical environment of the body.

 

B = Nanobiotechnology devices that can derive energy from biological

metabolism. Many nanomedical devices will be powered by the fuel

available inside the human body. A common idea is to take our own

glucose-oxidizing enzymes and use them as a fuel cell for the nanobiobot.

 

C = Nanobiotechnology devices capable of copying themselves by

molecular self-assembly.

 

Which creates a completely realistic animat formula. A + B + C = a

self-replicating nanobiobot capable of living inside the human body

powered by our own metabolic energy.

 

Of course, scientists are not intentionally putting A together with B

and C. No one is trying to create the first true animat—they're just

working on rudimentary forms of artificial life or synthetic biology.

But if, as part of this benign research initiative, they happen to

create nanobiobots some of which have traits A or B or C—our

definition of life will have changed forever.

 

Does this mean we will immediately cease to be human? Probably not.

The most probable scenario is that an array of proto-animats will be

carried as an evolutionary adaptation that enhances biological

function for generations before any of them become an essential part

of our phenotype. After that...

 

If the animat test described here is not sufficient, let it stand as a

challenge for the development of a completely rigorous test for the

unequivocal identification of nonbiological life forms. The larger

point is that humanity must initiate a search-and-test protocol now in

order to prepare for the arrival of the literal alien from within.

 

Nanofabricated animats may be infinitessimally tiny, but their

electrons will be exactly the same size as ours—and their effect on

human reality will be as immeasurable as the universe. Like an

inverted SETI program, humanity must now look inward, constantly

scanning technology space for animats, or their progenitors. The first

alien life may not come from the stars, but from ourselves.

 

© 2006 Salon.com. The ideas stated here reflect the personal views of

the author. They are in no way related to his professional affiliation

with Alfred University.