John Dewey's work inspired Simon, Churchman and Ackoff. To encourage rigorous thinking, Dewey makes the rallying cry: Synthesize don't just analyse. Operational research does analysis well. However, our understanding of its conjoint twin, synthesis, may need some more pragmatic rationalization. Synthesis, often confused with systems thinking, is thought to be a process of engagement with alternative conceptions (interpretations) of the problem domain; conceptions that suggest a different solution set. Therefore, this paper explores the proposition that operational research needs to engage more synthesis to complement its skill at analysis. Why synthesis is required, what it is and how it works is explained. Two case studies are provided to demonstrate the mechanisms of synthesis as one part of strategic thinking.