© 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.

2.3 Alternative Models of Machine Replication

Subsequent theoretical work explicitly derived from von Neumann’s research effort has focused mainly on the molecular biological analogies that can be drawn. For instance, Laing [557-563] employs a hybrid cellular-kinematic model (Section 3.8) of machine construction and shows that neither existing natural nor artificial machines need be bound to follow the “classical” replication paradigm. In the classical paradigm, a program (DNA in living systems) is first interpreted to construct a machine (ribosomes and the other molecular machinery of a cell) and then is read a second time to make a copy of the program for insertion into the newly constructed duplicate machine (DNA replication in living cells). The principal contribution of Laing is to suggest reproductive strategies other than direct analogs to the known biological process. In this new conception, a machine is able to identify all of the components of which machine systems are comprised (not merely a subset as in the von Neumann cell system), and can access all of an existing machine structure without requiring dismantling of the system (as would be required in the von Neumann model). For example [558], to produce offspring a parent could begin with a description, or with a set of instructions for construction, or with a set of instructions for a description, or with a description of a set of instructions for a construction, or with a description of a set of instructions for a description, or with a constructor of a describer of a set of instructions, etc. Once these and other similar concepts are brought to bear on the problems of machine reproduction, many alternative reproduction strategies immediately become apparent – a selected few of which are briefly reviewed below.

Last updated on 1 August 2005