Nanotech Thoughts

Posted to sci.nanotech, November 15, 1989

I've been reading sci.nanotech for the past few months, after reading Engines of Creation earlier this year. Since the forum seems to be a little slow lately, perhaps you'll be interested in my two cents on the subject. Bear with me if this seems a bit obvious at first...

The Blob

After reading Engines of Creation, with all its wondrous descriptions of assemblers and their possibilities, its touching faith in AI (and the extent it relies on Technical AI's for projections of the future), I decided to try and visualize some aspects of this whole idea. Grey Goo, with its doomsday scenario seemed like a good place to start.

So imagine that we have a future nanotech factory. As described in Engines of Creation, there is no assembly line. Instead, we have numerous vats, filled with liquid working materials, and assemblers. These assemblers are produced (or programmed ?) for a particular construction job. They take materials out of their environment and build the product. They also build other assemblers as needed.

Lets assume that this has all been thought out well and that Grey Goo is not just going to pop up in the factory by accident. Instead, we'll assume a disgruntled employee (playground-berserker-nerd type) has decided to take revenge on his employers by scaring them with a Grey Goo attack. He cleverly programs it to appear in the vat, eat the product and then die off. Unfortunately, he makes a programming error and the goo is off and running without restriction.

Let's assume that the goo has a doubling time of an hour. In ten hours it multiplies by 1000. In a day or so, it multiplies by a million. This is under ideal conditions. In "real life", the goo is constrained by the availability of materials and energy.

So in our factory, the Grey Goo becomes active when the product is taken out of the vats (as planned by our evil genius). It eats the product, but does not stop there as was specified. Instead it continues to replicate, taking materials as it finds them. The first thing anyone notices is a film sliming across the floor and up the walls, over the lights, etc. In effect, we've created The Blob.

Yechh -- What a Mess

Cleaning this up is a problem. Not that assemblers are indestructible. Lots of things might destroy them -- chemicals, radiation, cutting off their food supply (hard). The problem is that you have to get it all. If you miss any, you are back to square one in a day or two. We can imagine our clean-up crews frantically fighting this thing again and again, until finally they lose. They lose when a bit of Grey Goo gets into the outside world. If it makes it inside a human or other animal, we've all had it.

Inside any living organism, it probably finds a nearly ideal situation -- lots of energy and building materials. A human infected with this doesn't even know it at first. He carries it away, spreading it all over the place during his normal routine. Small amounts of goo are being left behind when he touches surfaces (or other people), they are present in exhalation, wastes, etc. Pretty soon the area around the factory is thoroughly contaminated, people are dropping like flies from being used as raw materials, and the goo is unstoppable. A fatal disease with a fast vector like this could kill everyone on the planet in days. Next scene, the entire Earth is covered with goo and life is boring.

The Deadly Dust

Note that the form of Grey Goo I've described is really mild. I pictured it as a slime, all clumped together and easy to spot. There's no reason for the assemblers to clump, and it makes it much harder to handle if it doesn't. Also, I just described goo that wants to grow and has no preferences as to where. If instead the goo homes in on good sites (actively searches for materials), it would be much worse. So instead of The Blob, imagine a Deadly Dust, which consists of invisibly small particles. These remain suspended in air, drifting until they find a good spot to set up replication (for example, when they are inhaled.) Then they go to work and pump out copies at the maximum rate.

Now our goo is never even spotted by the clean up crews. The first they know is a week later when everyone around starts to die.

Blue Goo -- Our Hero

Well, Grey Goo is mentioned in Engines of Creation, and the solution given is The Active Shield -- also known as Blue Goo. This goo is tame. It eats the dangerous Grey Goo and the world is saved!! Only I have some problems with Blue Goo...

It'S Everywhere!

First, you can't apply the Blue Goo to a mess like the one above after the fact. If you tried, you'd have two problems. First, you might not have spotted that there was a problem until it was far too late. Second, it might be more than Blue Goo can handle.

After all, Blue Goo is necessarily much more complex than Grey Goo (Blue Goo has to be much more selective!) This means that it will probably replicate slower. So a given amount of Blue Goo can't catch up to the same amount of Grey Goo. In order for Active Shields to work, they have to be in place all the time, so they can stop Grey Goo before it gets started.

In Engines of Creation, Drexler envisions Blue Goo as the world's immune system. I was not convinced, for several reasons.

First, where exactly does the Blue Goo live ? The answer has to be everywhere, if you really want protection against deliberately created Grey Goo (or exotic accidents). And by everywhere, I mean EVERYWHERE!

It has to be inside the body of every human you intend to protect, so that it can't eat them. Right here, we have a show-stopper, as far as I'm concerned. There are people in this country afraid of fluoridated water! There is no way you are going to convince large numbers of people to allow you to infect them with an artificial disease in the name of protecting them! Not to mention that people in this forum have discussed the possibility of mind control ("artificial conscience" indeed!) via nanotech devices. Let any rumor of that possibility get out, and you can forget it! And even the most trusting person is going to be worried about the possibility of sleepers or bugs in the design of the Blue Goo. Are you willing to trust U.S. Government-designed stuff in your body?

Many of you will make the argument that the progress of a technology is inevitable, and we have to make the best of this situation. There will be the possibility of Grey Goo, and this is the only way to protect ourselves. I think the average person would rather see the whole technology stopped cold rather than risk this situation. But they will probably see the threat too late. Plus there is always military goo, which will be developed even if all governments publicly renounce the technology. I see this as leading to a rather bleak picture (see "We're Doomed" below), but perhaps not. For the sake of getting on to the next point, let's assume that a benevolent, farsighted, brilliant bunch of idealists creates the perfect Blue Goo and releases it without consent of the population.

Well, the Blue Goo has to exist not just in humans, but in their food animals and plants, or Grey Goo can still wipe us out. In fact, it has to exist in all living things all the way down the food chain from us. And in other crucial parts of the ecosystem -- we wouldn't want to try to do without trees or algae in the ocean producing oxygen for us! We might as well think big and assume that Blue Goo is in every living thing on Earth....

This still doesn't protect against really nasty Grey Goo. I would think it would be possible to create a Goo that would avoid living cells. If nothing else, there are areas on Earth (deep oceans, arctic ice, upper atmosphere) where life would be scarce enough to avoid. This type of Goo would have to wait until it was widely distributed enough (and massive enough) to do damage. At that point, it could produce poisons of some kind in quantity.

To handle this situation, Blue Goo is going to have to pervade the inorganic world as well as the organic. It will have to filter air to check for Grey Goo, and crawl about surfaces looking for it, and generally be omnipresent.

To say the least, I'm not convinced this is reasonable.

One Goo To Another

So, I'm envisioning this Blue Goo existing inside all my cells. How does it spot Grey Goo in the first place ? Blue Goo is going to be crawling over all the parts of my cells, fingering them and looking for an unusual pattern. After all, it's not like it can extrude little eyeballs and look around for problems. And there's no way for Blue Goo to know what should be in the cell anyway, at least not in any detail. To do that would require so much information storage that the Blue Goo would be huge, and as complex as the cell itself. Some centralization might help here, with Blue Goo cops communicating back to a central intelligence, asking if each and every strange thing is part of normal cell contents. Even so, Grey Goo could surround itself with perfectly ordinary organic material. It could look like some piece of debris inside the cell, or a piece of DNA, or cell wall. Asking Blue Goo to spot this is basically asking it to know everything there is to know about the organism. And remember that it has to know it about each and every type of life on the planet.

We can't redefine the task of Blue Goo to that of preventing cell damage without spotting the Grey Goo that's causing it. For one, a cell could be subverted by the Grey Goo, and seem to work perfectly well, except that it's pumping deadly chemicals into the body. The Blue Goo can fight effects all it likes, but if you have a heart attack, no cell-by- cell strategy will save your life. The Blue Goo would have to know system-wide effects, or else recognize the Grey Goo.

If we just tried to keep cells alive, we would also have all sorts of effects on the development of organisms. And of course, we want some cells (and animals) to die! How else would they eat each other? How would we eat them? I can imagine what would happen if we tried to eat a hamburger full of Blue Goo! First, it tried really hard to save the life of the cow, and of the wheat in the bun. Then it found itself in the hostile environments of packing plants, ovens, etc. and did its best to keep cells alive. Then it wound up in your stomach, even more hostile! Can it save the beef cells from your stomach acids? Tune in tomorrow!

Again, I think Blue Goo of this sophistication is unlikely.

My Goo is Bluer than Yours

While I'm at it, I should also point out that Blue Goo has to recognize itself. If nothing else, so that it doesn't waste resources fighting with itself. And this would seem to mean that there is only one kind of Blue Goo, since it would naturally attack any competing kind. So we really need either a covert introduction of Blue Goo or international agreement on it (with or without consent of populations). And once introduced, that's it. Any improved Blue Goo would have to displace the stuff already in existence, which is supposed to be impossible.

Captive Goo, Trojan Goo

Of course, it won't be impossible, because Blue Goo will have to be able to recognize itself. This means some kind of recognition codes. And that leads to trouble. First off, since Blue Goo is everywhere, capturing a specimen for analysis is trivial (in fact, it's impossible not to! It's inside your equipment already, scanning for Grey Goo!)

Once you have a specimen, you can determine the recognition codes. They have to be stable, since Blue Goo will be meeting itself all the time, and meeting different generations and variations of itself from other organisms that you ingest. If the recognition scheme can be broken or copied from the design of the Blue Goo, then we can build a Trojan Goo that fools Blue Goo. This seems to be another fundamental objection.

Hothouse Assemblers

We could of course control accidents. We could even control many types of sabotage, if we are willing to limit our use of nanotechnology. For example, we could design all assemblers only to work in the presence of strong magnetic fields, or only when certain chemicals are present, or only when receiving radio signals. When this signal is not present, the assembler dies. This would represent a sort of dead-man switch, and could be used to control even Grey Goo. This restricted nanotechnology would still be useful for all the envisioned medical and industrial applications. Just keep the affected people and plants inside the required safety field. Any nanodevices straying out of that field for any reason will die.

However, we would have to prevent any assembler from building an assembler that did not have this dead-man switch in it. That means an unrealistic amount of human self-restraint (there's still military goo to consider), and pretty sophisticated analysis of the functions of assemblers. I don't think anything less than a human-equivalent AI could be counted on to spot an assembler designed to build nonstandard assemblers. Especially since several jobs could be submitted in pieces, and only in combination create the illegal assembler.

Military Goo

The summary below ("We're Doomed") could be applied equally well to biological warfare, except for two points:

First, there less connection between artificial plagues and useful genetic engineering than there is between Grey Goo and replicating assemblers (needed for any large project with nanotech).

Second, plagues look like a nasty, hard-to-control weapon, but Military Goo is nearly the ideal weapon.

For example, suppose the following relatively simple use of nanotechnology: You build some goo that spreads from person to person and does not replicate endlessly. Instead, it makes some simple changes, only to a small number of cells in the body. It could work in some completely inaccessible place. In this spot it builds a small machine that can receive radio instructions. On command, this machine can synthesize various drugs/hormones and introduce them into the blood stream. Once the machine is built, the body is tagged to prevent later visits by the goo.

Now we have the perfect mechanism for control of enemy (or your own) populations. From orbit, areas can be blanketed with instructions to the implanted devices. They can kill, sedate, or otherwise modify behavior. Every dictators dream! With the possibility of this kind of power in the works, nanotech devices will undoubtedly be developed, if only to protect our own people (right).

We're Doomed

So I'm left with the following chain of reasoning about all this:

  • Lots of people think self-replicating assemblers are possible.
  • We will build them if they are possible, for the large benefits.
  • With some probability, Grey Goo will be produced, accidentally or deliberately as a weapon. It is one of the simplest uses of the technology, after all.
  • Grey Goo cannot be defeated without Blue Goo already in place.
  • Blue Goo cannot be made powerful enough to defeat reasonable (or even simple) Grey Goo, for the following reasons:
    • it can't cover all the places Grey Goo might arise.
    • people won't let it inhabit them
    • covering the whole ecosystem is necessary
    • good coverage of inorganic world necessary as well.
    • it can't spot Grey Goo when it occurs.
    • Blue Goo can be captured and its recognition signals forged.
  • Conclusion: Someday, we will all be eaten by Grey Goo.

Proof :-)

You wonder why we have not been visited by aliens? Well, this is why. A simple scenario holds up very well:

On many worlds over billions of years of time, life arises.

Intelligent life is produced by natural selection. Nothing in this selection process prepares an organism for a radical change in its niche, or abilities.

Technology is either too hard (no problem), or far too easy to master. If a species becomes technological, it suddenly finds itself in a situation for which evolution has not prepared it. It is as if members of the species suddenly grew to ten times normal size. How would they adapt to this before doing something fatal ?

The species inevitably destroys itself with some mistake. Inventing nanotechnology is one good way...

A Way Out Way Out

There is a way out of all this, and I consider it far more likely than the invention of Active Shields. After all, members of this group have talked about AI being necessary for Active Shields anyway. We've also talked about being able to map the connections of the brain and save personality. Drexler talks about Technical AI's that are equivalent to human brains, but as much as a million times faster.

The simplest scenario that gets us out of all these problems is that someday before The End, we build a nanotech copy of a human consciousness. Actually, we build a community, and we give them assembler tools to work with. They think a million times faster than we do. To them, assemblers are as slow as hammer and nails. They can easily monitor all the activity of human civilization and just prevent anyone from doing anything dangerous. Unlike technical AI's or simpler Goo machines, these nanohumans will understand human culture. They won't waste time touring your cells waiting for Grey Goo -- they will know that it comes from factories or labs. They can easily track all work going on in such places, since we run in super-slow motion compared to them.

In fact, such nanohumans would quickly (very quickly) become the leading edge of civilization on this planet. If human-level consciousness is possible at nanotech scale, then I find the whole idea of Technical AI's serving us absurd. Instead, they will develop and leave us behind. The Active Shield will be a nanoculture that protects us from our own carelessness out of sentiment.

Imagine the first steps in this process. We would map a particular individual's nervous system into nanomachinery. Once the copy is built, we would study it for awhile. Its replicated nervous system would be run at greatly reduced rates (equivalent to neuron firing times), so that we can talk. When its responses check out with the original, and it seems sane, we have our first nanohuman. Depending on what's been done with the rest of the body, it even looks human. A robotic body under the control of the nanobrain we've built seems simple in comparison. So we have the first android copy of a human (empty-headed, of course, since the brain is the size of a few cells). Already, we've invented immortality....

Speed its thought processes up by a factor of two, and we have a creature that can out-compete the human race, if allowed to reproduce. If we sped the mind up to maximum rate, and built a body scaled down and with response times to match, we have the first real nanohuman. Suppose a group of people are copied down to this level. If they really ran a million times our speed, we would flip the switch, and that's the last we would ever see of them. A minute of our time would be two years of theirs. You could get a good sized colony started up by then. After an hour, over a century has passed for them. Even starting from a few individuals, a reasonably scaled reproduction rate would have cities spread all over your lab by then. In a day, who knows what you would be looking at. Certainly, the nanoculture has pervaded the planet, and installed any necessary safeguards on our technological development by then.

Why would they? One good reason is that they would be us. If the nanoculture knew that the world was full of interesting personality patterns, which would give it a rich mental diversity (as necessary to them as genetic diversity is for us), then why not go and get it? In the first hours of the colony's existence, a program would be started to make nanocopies of some or all of the world's population. At some point, a nanocopy of you becomes conscious, and joins in the fun. Naturally, you would protect your organic self. Why not, with such huge resources?

For us organic humans, things might suddenly get strange. Before the press reports of the creation of the first nanoculture even reach us, we might find ourselves changing. We might find everyone around getting younger and healthier, calmer, smarter, more talented, or whatever we desired...It would be our true desires as well, since the changes would be made by nanocopies of ourselves. The nanotech devices monitoring your health and happiness might be multiple copies of your personality, frozen into a helpful state of mind, so that they don't get bored....

This civilization might last forever. Not just the organic one, but the nanotech one as well. After all, it's much more durable than ours. If nothing else, it can make copies of itself. At some point, perhaps it would build a few checkpoint asteroids. These rocks would be encoded with the personality patterns of all existing nanohumans at the time, and sufficient hardened assembler machinery to bring them all back to life. The checkpoint could be sent somewhere safe, with instructions to activate if no signal arrives from home every so often. Perhaps some would be sent to random places in the galaxy, and their destination erased from the memory of the senders. These would arrive and recreate civilization there as a backup against massive destruction.

If this all starts off before the end of our lifetimes (and we can extend with cryonics), then we might be these nanohumans. Someday, a copy of me and a copy of you, resurrected for fun from archival storage, may gaze at some distant star and talk about how far we've come, and how when we were young, some people thought the human race would never last....

Very Little Green Men

This is my answer to Active Shields, and the "proof" in "We're Doomed". And it's my answer to why we have no alien visitors.

Since intelligent creatures either invent nanotechnology, and nanoculture, or else they destroy themselves :-), then it follows that any visitors will be nanoaliens, and very advanced ones as well (the time needed to cross between stars is eons for nanocreatures.) Since there has been plenty of time for such creatures to have developed, either it can't happen (we really are doomed then), or else they are out there already. If so, our CETI programs are barking up the wrong tree. We shouldn't be looking for slow signals. We should be looking for communication between creatures a million times faster than us, with far better error-correction algorithms. Their messages to one another will use the maximum bandwidth, and be so efficient as to be indistinguishable from noise. Of course, there's no point in looking for this. We couldn't understand it if we found it. And in any case, a survey for all intelligent life in the universe is a reasonable class project for some bored nanostudent. We don't need to look for nanoaliens, since they've certainly found us.

If they came here, what would they do? It's possible that they would have ignored us, the way we would ignore any uninteresting place. It's possible that they would absorb us, but that should have happened already (of course, I can't prove I'm not working through some type of simulation right now...) It's also possible that they've done both.

If I were a visiting nanoculture, and I ran into the human race, I might be interested in it. I wouldn't want to wait around long enough to talk to them though, since they are so slow. The natural response would be to study their nervous systems in detail, and then map a few down to nanoscale. At that point, I could question them in detail, and evaluate the species. If they were uninteresting, and likely to remain so, that would be the end of it, and the nanoculture would leave. On the other hand, it might decide to set up a permanent nanoculture here.

My assumption here is that with the nearly infinite resources a nanoculture would have, it can afford to try many options. It could create one nanocopy of all humans, and let that nanoculture evolve. It could create another copy and mix it with alien patterns. It could create any other interesting combination. It could do all of this and also leave the organic society alone to develop. The only "cost" they incur by doing this would be the time to make a copy of the machinery/culture needed to get a project started. From that point, the copy extracts resources and builds as necessary to complete the project. The benefit they get is to extend themselves in possibly new directions. The nanoculture is the ultimate information society. A few billion new patterns of consciousness might represent a gold mine of information. Comparing this trivial cost with the possibly large benefit could mean that the nanoculture is continually converting organic intelligence to nanocopies, just on the off-chance that an interesting new pattern has arisen.

Just to finish this article off with a bang, let's consider one last possibility. I've talked about what could happen if a nanoculture discovered us. As I've said, it should be the case that this culture already exists, and already has found us. In that case, perhaps all of this already has happened. There might be a nanocopy of you right now, living as part of a nanocopy of human civilization. This civilization was started by nanoaliens thousands or millions of years ago, when human intelligence first became worth copying. It has continued since that time, copying every new personality that nature produces, including all of us, at each important change in our lives. These copies have gone about their own activities in the nanoculture, perhaps copying themselves for various reasons. By now, there might be thousands of nanohumans, derived from your personality at different points in your life.

The simplest concept is that the nanohuman culture is somewhere else, and the only thing here is some nanomachinery in each of us to harvest this crop of patterns produced by nature. But of course, the nanoculture might be all around us. If it were convenient, the nanoculture could edit our minds and sense impressions in any way they liked. There could be a glowing nanocity right outside my window, and my retinas might not register it. Or I could be seeing it, but continually forgetting about it....

Parting Shots

There's no point in continuing along these lines, since I've now proposed a theory that can't be refuted. Since I could argue that you can't trust your sense impressions, or even your thoughts, any argument against the hidden nanocity could be a production of the nanoculture attempting to conceal itself. In science, theories that can't be refuted aren't good theories.

If I were to summarize the point of this posting, I guess it would be that this forum follows the same pattern that most technological forecasting does. In the short term, it's too optimistic. It will take us a long time to get some of the basic nanotechnology to work, and the process will be full of possibilities for disaster. In the long term, you are too pessimistic. The possibilities opened up by nanotech are limitless, and will change us drastically. To talk of artificially intelligent crash protection in cars (to name one recent topic) is absurd. Any one of the precursors necessary to bring about some of your trivial conveniences would also be enough to change human life forever.

Use some imagination!

by Michael Goodfellow.
For more, see Free The Memes!

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