A paper published in the journal Nanotechnology warns that fear of runaway self-replicating machines diverts attention away from other more serious risks of molecular manufacturing. The paper, “Safe Exponential Manufacturing,” published by the Institute of Physics, was written by Principals Chris Phoenix, Director of Research at the Center for Responsible Nanotechnology (CRN), and Dr. K. Eric Drexler, a pioneering nanotechnology theorist and founder of the Foresight Institute.
Drexler had cautioned against self-replicating machines in his 1986 book Engines of Creation. The idea became known as ‘grey goo’ and inspired a generation of science fiction authors. In this article, Phoenix and Drexler show that nanotechnology-based fabrication can be completely safe from out-of-control replication. However, they warn that for other reasons misuse of molecular manufacturing remains a significant danger.
“So-called grey goo could only be the product of a deliberate and difficult engineering process, not an accident,” said Phoenix. “Far more serious is the possibility that a large-scale and convenient manufacturing capacity could be used to make incredibly powerful non-replicating weapons in unprecedented quantity. This could lead to an unstable arms race and a devastating war. Policy investigation into the effects of advanced nanotechnology should consider this as a primary concern, and runaway replication as a more distant issue.”
Goo vs. Paste
By Chris Phoenix - September 2002
The first use of the term "Goo" was in the phrase "Gray goo" (see below). Gray goo is a mass of small, destructive, self-replicating nanorobots, so the word "goo" implies a capability for self-replication. Of course, most nanorobots will not be capable of duplicating themselves (just as normal-sized machines cannot reproduce), and most nanorobots will not be destructive. Naive nano-thinkers may imagine self-replication as part of every nanomachine's functionality, thinking this would be more convenient, but self-replication is quite difficult and would make any nanomachine bulky and inefficient. In practice, it will almost always be better to manufacture a sufficient quantity of simple nanomachines in advance. It is tempting to call any mass of small nanomachines a "goo"; however, uncontrolled self-replication is one of the largest perceived risks of nanotechnology, and we need to be quite clear about which designs pose that risk and which do not.
Gray goo is a notorious (and usually misunderstood) fear that is an outgrowth of MNT. The idea, which is far too simplistic, is that a small molecular manufacturing system could duplicate itself and forage in the wild, turning biomatter into copies of itself on a planetary-wide scale. In fact, gray goo would be quite difficult to design, since it needs onboard control, chemical preprocessing, environmental protection, etc. in addition to the molecular manufacturing system. MNT manufacturing systems could not possibly "mutate" into gray goo (any more than your drill press and lathe can) and would even be hard to adapt deliberately. Products of MNT would omit one or the other of the required functional units, so would be similarly incapable of becoming gray goo. Any goo-like product is inefficient and no one would want to use it. It's not even a very good weapon. Still, there are a couple of reasons why someone might deliberately try to build and release it, so we need some policy to deal with that--though similar policy is required by other, non-goo, MNT products.
Gray goo has been a major impediment to sensible discussion about nanotechnology. Gray goo may be the reason why some scientists have fought so hard (with so little evidence) to avoid admitting that molecular manufacturing is possible. And mention of biosphere-destroying nanobots has appeared all too often in writings ostensibly about near-term nanotech risks like nanoparticles.
To distinguish between dangerous devices and useful devices, this site uses "goo" to refer to a mass of small machines that can self-replicate, and "paste" to refer to a mass of small machines that cannot self-replicate. Thus, for example, a "Medical paste" would be a bunch of non-replicating nanobots with a specific medical task, such as cleaning and closing a wound. Medical paste, and indeed any paste, cannot run amok and eat the biosphere; the ability to do such a thing would require a massive amount of complexity, and would be completely lacking from any special-purpose design. A "Medical goo"--a medical paste with self-replication built in--might in theory pose such a risk. However, as pointed out by Robert Freitas, author of Nanomedicine, such a device would be both unnecessary and undesirable.
The Various Goos
Assembler: A small nanomachine designed to construct other nanomachines, including copies of itself. Assemblers were used in Engines of Creation to describe the manufacturing capability inherent in molecular nanotechnology. The word "goo" has never been applied to assemblers; they are included in this list because of the fear that a random "mutation" (in other words, magic or very poor design) could turn assemblers into gray goo. Although a well-designed assembler would have numerous safeguards against uncontrolled replication, such as spontaneous combustion if exposed to oxygen, it now appears that assemblers are completely unnecessary to achieve the benefits of nanotechnology. Monolithic factories, containing huge numbers of assembly stations, would be able to work more efficiently, since an assembler would have to navigate and communicate as well as build and a factory does not have these problems. [KED; definition written by CP]
Blue Goo - opposite of Grey goo. Beneficial tech, or "police" nanobots. The trouble with blue goo is that it could easily make too much of itself--and it's hard to clean up, even to replace with a later version. The idea of "Blue goo" was apparently invented in 1989 [link]; since then a lot more work has been done on how
to stop gray goo, especially in this paper by Robert A. Freitas Jr. "Some Limits to Global Ecophagy by Biovorous Nanoreplicators, with Public Policy Recommendations", and it appears that (for example) a full-blown worldwide atmospheric infestation can be cleaned up with a mere 88,000 tons of pre-built, non-replicating dragnet robots. [Alan Lovejoy; definition written by CP]
Gray Goo or Grey Goo - destructive nanobots See Star Trek scenario. Vast legions of destructive nanites. Supposedly created by accident, they are nano-scale or "atomic-precision" robots capable of precise, molecular control over chemical reactions, programmed to make unlimited copies of themselves, and capable of surviving and gathering supplies in a wide range of environmental conditions. Left unchecked, they would basically convert everything they touch into more of themselves, or consume and digest it for energy [ecophagy]. Either way, a gray goo would be bad news.
Green Goo: Nanomachines or bio-engineered organisms used for population control of humans, either by governments or eco-terrorist groups. Would most probably work by sterilizing people through otherwise harmless infections. [AS]
Golden Goo: Another member of the grey goo family of nanotechnology disaster scenarios. The idea is to use nanomachines to filter gold from seawater. If this process got out of control we would get piles of golden goo (the "Wizard's Apprentice Problem"). This scenario demonstrates the need of keeping populations of self-replicating machines under control; it is much more likely than grey goo, but also more manageable. See also LOR Goo and LOR Paste. [AS - Originated on sci.nanotech 1996]
Khaki Goo: Military Nanites; see grey goo. [AS]
Pink Goo: (humorous) Humans (in analogy with grey goo). Pink Goo refers to Old Testament apes who see their purpose as being fruitful and multiplying, filling up of the cosmos with lots more such apes, unmodified. [Eric Watt Forste August 1997]
Red Goo: Deliberately designed and released destructive nanotechnology, as opposed to accidentally created grey goo. [AS]
ÜBERGOO: A related term to grey goo, used (jokingly) to refer to the mistaken idea that during the singularity powerful technologies would decimate non-transhumanists, and that some transhumanists would see this as desirable (which is clearly against the Transhuman Principles). [Dale Carrico 1996]
LOR Goo: Lake Ocean River. See also LOR Paste (below). Nanites that both clean up and harvest the oceans, rivers, and lakes--gathering raw materials, such as precious metal atoms, and cleaning up spills, old waste, wrecks, and other dangerous sites. Cleaning the bad stuff also allows for creation of good stuff, such as more LOR goo. However, it would be hard to recover the goo after it has gathered the desired harvest, and a simple programming error could turn LOR Goo into Gray Goo. LOR Paste would be considerably safer, and LOR Goo should probably be made illegal. [uhf]
The Various Pastes
ACE Paste: Atmospheric Carbon Extractor. Harvests the greenhouse gases for Carbon, to be used for diamondoid fabrication. Larger than most pastebots, because it has to be collectible afterwards. A well-designed paste could harvest 100X or more its empty weight. ACE Paste may not be necessary, because large fixed installations might be more efficient. [uhf. CP]
Garden Paste: Utility fog that is used in place of, or in combination with, your garden soil, and is able to be "dialed in" to match the optimal soil composition requirements for each and every plant you have. It will change according to each plant's needs for water, nutrients, and soil density. It will also form shade when and where needed, automatically, or upon request. Further, it will keep out moles and gophers by forming instant temporary barriers; store sunlight via solar cells, for use on overcast days; detect and drive off harmful insects, perhaps via insect-specific pheromones; retain water and minimize evaporation (sophisticated networks of Garden Paste could include an irrigation system), and even identify and remove plants started via airborne propagation [sometimes referred to as "weeds"]. [uhf]
LOR Paste: Lake Ocean River. See also LOR Goo (above). Nanites that cleanup and harvest the oceans, rivers, and lakes--gathering some materials, such as heavy metal molecules, and cleaning up spills, old waste, wrecks, and other dangerous sites. LOR Paste would have limited or nonexistent fabrication ability, making it smaller, more efficient, and easier to design than LOR Goo--and much safer. Heavy metals would have to be stored onboard, a form of encapsulation, but undesired organic compounds could be broken down into harmless molecules and released. [uhf. CP]
Medic Paste: Applied directly to external wounds, and internally via ingestion or shot, for rapid diagnosis and treatment. Carries telemetry nanites as well, in order to provide real time feedback to the doctor, for tricky diagnostic and/or treatment decisions. [uhf]
Utility Fog: A mass of robots with twelve legs apiece forming a microscopic truss structure. Capable of changing shape, and perhaps color, in response to external commands. [JH]