If all the theories pertinent to systems engineering could be discussed within a common framework by means of a standard set of nomenclature and defi… - A. Wayne Wymore

The problem of the design of a system must be stated strictly in terms of its requirements, not in terms of a solution or a class of solutions.

[In the year 1957] I have just returned from an exciting meeting of the American Society for Engineering Education where I heard a paper on the new discipline of systems engineering. It is no longer sufficient for engineers merely to design boxes such as computers with the expectation that they would become components of larger, more complex systems. That is wasteful because frequently the box component is a bad fit in the system and has to be redesigned or worse, can lead to system failure. We must learn how to design large-scale, complex systems from the top down so that the specification for each component is derivable from the requirements for the overall system. We must also take a much larger view of systems. We must design the man-machine interfaces and even the system-society interfaces. Systems engineers must be trained for the design of large-scale, complex, man-machine-social systems.

[The process of system design is]... consisting of the development of a sequence of mathematical models of systems, each one more detailed than the last.