„Managers are not confronted with problems that are independent of each other, but with dynamic situations that consist of complex systems of changing problems that interact with each other. I call such situations messes. Problems are extracted from messes by analysis. Managers do not solve problems, they manage messes.“
— Russell L. Ackoff Scientist 1919 - 2009
1970s, The future of operational research is past, 1979, Cited in Donella Meadows (2008) Thinking in Systems: a Primer. p. 1.