ABSTRACT
Control theory, which is more closely related to adaptivity than to complexity, split off and became a solid but separate domain within engineering. Communication theory, whose interest surely does focus on complexity, did flourish—also as a separate domain—and contributed as well to the foundations of computer science; but its ties to a general systems theory were lost, and the dream of creating such a theory has nearly died. The widely accepted doctrine of "structured" or "top-down" programming is aimed at using hierarchy in the program architecture to assure comprehensibility for programmer as well as user. Near-decomposability is of great assistance in gaining an understanding of hierarchical complex systems. The explanation of thinking in terms of symbolic processes is summed up in the physical symbol system hypothesis. The symbols are patterns of electrornagnetism stored in memory, their physical nature varying with the age and model of the computer.
