War and peace what's the difference?

At one level, the question posed in the title of this contribution can be quickly dispensed with: war is violent and peace is, well, peaceful; in other words, peace is the antithesis of war. This is certainly the common-sense view, and it is one usually reinforced by the media. Journalists, after all, are interested in change: theirs is a world of news (what is new), of events, discontinuities and drama. What could be more dramatic than the change from one thing into its opposite? Historians, by contrast, are often interested in continuities, and it is this approach that informs this essay. What do war and peace have in common? Answering this question is particularly important if we hope to understand transitions: the transition from peace to war and the transition from war to peace. Perhaps we can also take a cue here from the natural sciences: how can one thing change into another - a bulb into a plant, a liquid into a gas - unless it has already begun to resemble it?