"A.D. Hall's classic account of the methodology was based on his experience with the Bell Telephone Laboratories. Hall sees systems as existing in hierarchies. In systems engineering, plans to achieve a general objective must similarly be arranged in a hierarchy, with the systems engineer ensuring the internal consistency and integration of the plans, The methodology itself ensures the optimization of the system of concern with respect to its objectives. This requires a number of steps, the most important being problem definition, choosing objectives, systems synthesis, systems analysis, systems selection, system development, and current engineering. With Hall, the system of concern is usually a physical entity."

“The problem solver needs to stand back and examine problem contexts in the light of different “Ws” . Perhaps he can then decide which “W” seems to capture the essence of the particular problem context he is faced with. This whole process needs formalizing if it is to be carried out successfully. The problem solver needs to be aware of different paradigms in the social sciences, and he must be prepared to view the problem context through each of these paradigms.”

“There exists an alternative to reductionism for studying systems. This alternative is known as holism. Holism considers systems to be more than the sum of their parts. It is of course interested in the parts and particularly the networks of relationships between the parts, but primarily in terms of how they give rise to and sustain in existence the new entity that is the whole whether it be a river system, an automobile, a philosophical system or a quality system.”

“Michael C. Jackson at Hull University Business School”

“Operational research OR is regarded by many as being in crisis. If OR is taken to be ‘classical OR’, this is indisputable … If, however, the definition of OR is widened to embrace other systems-based methodologies for problem solving, then a diversity of approaches may herald not crisis, but increased competence and effectiveness in a variety of different problem contexts.”

“Hard systems thinking is also accused of conservatism. It privileges the values and interests of its clients and customers, and lends its apparent expertise to their realization. It thus gives the facade of objectivity to changes that help to secure the status quo. In general terms, despite its many strengths and achievements, hard systems thinking is today thought of as having a limited domain of application.”

“The classification of a system as complex or simple will depend upon the observer of the system and upon the purpose he has for considering the system.”