© 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.

2.3.4 Replication by Component Analysis

In von Neumann’s cellular model, an embedded machine cannot send out an inspection arm to an encountered machine to identify all of its states. However, the cell space system could be redesigned to permit this. In such a system, an analyzing machine could examine an encountered passive machine and identify the type and location of all its cell automata. (The analyzer might of course have to penetrate the machine, thus altering its automaton states, so the inspecting arm would have to send out appropriate restoration construction signals.)

In von Neumann’s kinematic model, a machine ostensibly could identify all parts of the system and thus determine the type and location of all components. This opens the possibility that a machine system might, for example, replicate essentially two machines – one active, the other passive (or able to assume passivity under a signal from the active machine). This possibility and others have been explored by Laing [557-563] in a series of papers presenting alternative replicative strategies which include the following:

(a) Unilateral Reverse Engineering. Beginning with two identical machines, one active and one passive, the active machine reads the passive machine twice, producing one active and one passive machine, thus completing replication.

(b) Cooperative Reverse Engineering. Beginning with two machines (not necessarily identical) one machine reads the second, and makes a duplicate of it. Then the second reads the first, and makes a duplicate of it, active and passive status being exchanged. This result can be generalized to multiple machines [564].

(c) Inferential Reverse Engineering. By combining the capacity of machines to read machines with the Thatcher result, one can hardwire a machine to construct a second machine which is a duplicate of the original except for the hardwired part which produced the second machine. The original machine then reads the newly constructed partial duplicate, and infers what the missing hardwired part must be. The original machine then constructs the missing part, completing the replicative process. This result also explicitly confronts and overcomes the “necessary machine degeneracy” criticism of automata self-replication.

Last updated on 1 August 2005