Lieber 



According to the thesis of the present paper, the known general force laws 

 which refer to particular kinds of forces that are characterized phenomeno- 

 logically and thus identified by particular experimental arrangements, are par- 

 ticular aspects of the principle of maximum uniformity. This is also the inter- 

 pretation given here to constitutive relations, by which materials are identified 

 and phenomenologically distinguished in classical mechanics, and which are also 

 interpreted as restricted force laws emerging from the principle of maximum 

 iiniformity. In general, it is understood here that all forces in nature are linked 

 with, and are the concrete instruments of, a universal process of evolution 

 which develops according to the principle of maximum uniformity, and that the 

 general laws of force which express certain constant and thus uniform relations 

 between certain kinds of forces and space -time, are universal but nevertheless 

 particular aspects of the principle of maximum uniformity. 



In conclusion, it is significant to point out that the distinction between real 

 forces, as compared to forces of reaction, is based on the idea that motivating 

 forces are endowed with a causal aspect which is not expressed either implicitly 

 or explicitly by the laws of classical mechanics; and that the laws of classical 

 mechanics state a particular connection between forces which they define as 

 equilibrium, but which in reality does not define them. This simple connection 

 between forces acting on each and every material body in the universe, which is 

 termed equilibrium, is a very special aspect of uniformity in nature, which ac- 

 cording to these laws is a constant aspect of every material body in the universe 

 of classical mechanics. The known laws of classical mechanics accordingly do 

 not express the causal and, consequently, the historical and evolutionary aspect 

 of force. This stems from the fact that what they report about forces does not 

 in principle distinguish between motivating forces (the so-called real forces) 

 and forces of inertia or forces of reaction, such as emerge, for example, from 

 passive geometrical constraints when they are challenged by motivating forces, 

 which, according to the principle of maximum uniformity, are in fact endowed 

 with evolutionary thrust. 



The use of the principle of maximum uniformity —i.e., the derivation of a 

 process of evolution from it — calls for applying and maintaining over chrono- 

 logical time an agent which constantly impresses on the space-time manifold 

 nonuniformities which are manifested in experience, and in bodies subjected to 

 them, as forces. The nonuniformities so impressed on the space-time manifold 

 may be envisaged as active -stringent geometrical constraints. 



REFERENCES 



Lieber, P., "Categories of Information," Office of Research Services, Uni- 

 versity of California, Berkeley, Nonr-222 (87) AM-65-13, Oct. 1965 (pub- 

 lished in the Markus Reiner Honorary Volume, Elsevier Press, 1968) 



Lieber, P., "A Principle of Maximum Uniformity Obtained as a Theorem on 

 the Distribution of Internal Forces," Institute of Engineering Research, 



486 



