Clanking replicator

The term clanking replicator refers to an artificial self-replicating system that relies on conventional large-scale technology and automation. The term evolved to distinguish such systems from the microscopic "assemblers" that nanotechnology may make possible. They are also sometimes called "Auxons", from the Greek word auxein which means "to grow", or "von Neumann machines" after John von Neumann (this term is less specific and also refers to a completely unrelated computer architecture also proposed by von Neumann, so is perhaps not the best to use where accuracy is important). Whilst such a machine violates no physical laws, and we already possess the basic technologies necessary for some of the more detailed proposed designs, constructing a clanking replicator is not considered to be of major economic interest at ths time.

A self-replicating machine would need to have the capacity to gather energy and raw materials, process the raw materials into finished components, and then assemble them into a copy of itself. It is unlikely that this would all be contained within a single monolithic structure, but would rather be a group of cooperating machines or an automated factory that is capable of manufacturing all of the machines that make it up. The factory could produce mining robots to collect raw materials, construction robots to put new machines together, and repair robots to maintain itself against wear and tear, all without human intervention or direction. The advantage of such a system lies in its ability to expand its own capacity rapidly and without additional human effort; in essence, the initial investment required to construct the first clanking replicator would have an arbitrarily large payoff with no additional cost.

The idea of non-biological self-replicating systems was first seriously suggested by mathematician John von Neumann in the late 1940s when he proposed a kinematic self-reproducing automaton model as a thought experiment. See von Neumann, J., 1966, The Theory of Self-reproducing Automata, A. Burks, ed., Univ. of Illinois Press, Urbana, IL.

In fiction, the idea dates back at least as far as Karel Capek's 1921 R.U.R. (Rossum's Universal Robots).

In 1980, NASA conducted a summer study entitled Advanced Automation for Space Missions (http://www.islandone.org/MMSG/aasm/), edited by Robert Freitas, to produce a detailed proposal for the use of self-replicating factories to develop lunar resources without requiring additional launches or the support of human workers on-site. The proposed system would have been capable of exponentially increasing productive capacity and, in the long run, exploration of the entire galaxy within a reasonable timeframe. This study inspired the science fiction novel Code of the Lifemaker[?] (ISBN 0-345-30549-3) by author James P. Hogan. An early fictional treatment was the short story Autofac by Philip K. Dick, published in 1955, which actually seems to precede von Neumann's original paper about self-reproducing machines. Another example can be found in the 1962 short story Epilogue by Poul Anderson, in which self-replicating factory barges were proposed that used minerals extracted from ocean water as raw materials. Clanking replicators are mentioned briefly in the fourth chapter (http://www.foresight.org/EOC/EOC_Chapter_4#section01of03) of K. Eric Drexler's book Engines of Creation[?]. There was an article about a proposed clanking replicator system to be used for developing Earthly deserts in the October 1995 Discover Magazine[?], featuring forests of solar panels that powered desalination equipment to irrigate the land. In 1998, Chris Phoenix proposed (http://groups.google.com/groups?hl=en&selm=6f0nui%248ih%241%40news.nanospace.com) a design for a macroscale replicator on the sci.nanotech newsgroup, operating in a pool of ultraviolet-cured liquid plastic, selectively solidifying the plastic to form solid parts. Computation could be done by fluidic logic. Power for the process could be supplied by a pressurized source of the liquid.

As the use of industrial automation has expanded over time, some factories have begun to approach a semblance of self-sufficiency that is suggestive of clanking replicators. However, it is unlikely that such factories will achieve "full closure" in the near future so long as human labour and external supplies of spare parts remain conveniently available to them; there simply isn't sufficient economic value to be gained in overcoming the remaining dependencies. Fully-capable machine replicators are most useful for developing resources in dangerous environments which are not easily reached by existing transportation systems.

A clanking replicator can be considered to be a form of artificial life, and over sufficiently long periods would likely be subject to evolution. Since the error correction used by the system's genetic design data could be made extremely robust, and external updates would most likely be possible, the common science fiction theme of robotic life run amuck is not necessarily a significant short-term concern should such a system ever be created.

Other notable works containing clanking replicators:

• Berserkers, a series of books and short stories by Fred Saberhagen[?]
• The Forge of God by Greg Bear