Different methodologies express different rationalities stemming from — Michael C. Jackson

"In the modern systems approach, the concept "system" is used not to refer to things in the world but to a particular way of organising our thoughts about the world."

"We consider the notion of "system" as an organising concept, before going on to look in detail at various systemic metaphors that may be used as a basis for structuring thinking about organisations and problem situations."

"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."

"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."

"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."

"The problem solver needs to stand back and examine problem contexts in the light of different “Ws” (weltanschauungen). 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."