Kinematic Self-Replicating Machines
© 2004 Robert A. Freitas Jr. and Ralph C. Merkle. All Rights Reserved.
Robert A. Freitas Jr., Ralph C. Merkle, Kinematic Self-Replicating Machines, Landes Bioscience, Georgetown, TX, 2004.
6.3.3 Assemblers Have Not Yet Been Demonstrated
A few skeptics have argued  that regardless of whether or not assemblers are “impossible,” the fact that they have not yet been demonstrated in the laboratory means that there is no point in talking about them. Others [1427, 1428] note that assemblers are at best a very distant goal: “Being able to use an AFM tip to move around xenon atoms on the surface of a single crystal to write a company’s logo is indeed a remarkable achievement, but from here to the nanomechanical synthesis of objects shaped into the diamond lattice with atomic precision is a very long way.” While a lack of full demonstration to date is of course true, it is also true that the two key functionalities of molecular assemblers – namely, positional atomic-scale mechanosynthesis  and an artificial self-replicating robot with parts-assembly capability (Section 3.23) – have already been demonstrated in the laboratory. The principal reason for talking about molecular assemblers and nanofactories is the tremendous benefits that molecular manufacturing would bring (Section 6.3.5).
If this argument was applied to all of engineering research and development, then every technological advance would take us completely by surprise because we would be unable to discuss it until it happened. History serves to challenge this position. As noted elsewhere (Section 6.3.4), many advances were in fact discussed extensively before they were achieved. Many others which were not adequately discussed in advance, such as the possibility of cloning mammals, yielded unpleasant or disruptive surprises. Demanding that no discussion or investigation should occur until results are demonstrated is a philosophical position of fatalism, not a technical argument against any particular technology.
Last updated on 1 August 2005