Universal constructor

Von Neumann s machine is actually an example of a universal constructor. It must not only carry out logical operations (i.e. act as a universal computer), but must also be able to identify and manipulate various components. The universal constructor C must be able to both (1) construct the machine whose blueprint appears in symbolic form on its input tape and (2) attach a copy of that same blueprint to the machine once it is constructed. Self-reproduction is the special case where C s input tape actually contains the blueprint data for C itself. Alas, there are a few subtleties. 

B) A universal constructor UC can include a universal computer, for example a Turing machine (TM), and build a copy of the entire system from its description D(UC+TM). 

Moses, M. (2001). A physical prototype of a self-replicating universal constructor. Master s thesis, Department of Mechanical Engineering, University of New Mexico. 

The authors are grateful for helpful discussions and contributions from F. T. Selleck, R. A. Chong, E. C. Hohmann, and R. Nielsen of Fluor Engineers and Constructors. Inc. and R. Goffredi of the University of Wisconsin. We wish to express our appreciation to the management of Fluor Engineers and Constructors, Inc. for permission to publish this work. 

A. S. Smellie, CONSTRUCTOR, Oxford Molecular Ltd., Terrapin House, University Science Area, South Parks Road, Oxford, England (1989). 

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