I suppose most people will have had the experience of seeing a future pull away from the dock without them. The girl or boy turns you down, you don't get the job, and you have the awful sense that your life - or at least a life - has sailed without you, indifferent to the urgency of your desire to be on board. Often you can't quite get over it until the ship is well over the horizon, the last trace of smoke wiped from the sky.
And, almost invariably, what people see disappearing is assumed to be better than the life they actually have - even though common sense might tell you that disappointment rescues nearly as many people as it dooms. We're inclined to think we deserve what happiness we actually have while also suspecting that the accidents of history might have deprived us of more. And this tendency is pointedly at odds with the imaginations of writers and film-makers - who are, by and large, much more inclined to imagine things having gone wrong in an alternative reality rather than right.
We seem to be going through a blip of such alternative realities. First, there was Lionel Shriver's The Post-Birthday World, in which two different narratives flow from a sexual temptation, yielded to and resisted respectively. And now comes Owen Sheers' Resistance - which imagines that the D-Day landings failed and were followed by a Nazi invasion of Britain - and Michael Chabon's The Yiddish Policemen's Union, which supposes that attempts to create a Jewish homeland in Israel were violently rebuffed, and that Holocaust survivors found a temporary refuge in Alaska (a genuine pre-war proposal by Roosevelt's Interior Secretary Harold Ickes).
Historians tend to disapprove of such counterfactual narratives - and hotly so if they advance themselves as anything other than entertainment. Niall Ferguson's Virtual History, a collection of counterfactual essays by professional historians, quoted EH Carr as a representative example of the scorn for such exercises. Carr suggested that the historically disappointed were particularly prone to the fantasy that the world might as easily have been otherwise. "In a group or a nation which is riding in the trough, not on the crest of historical events, theories that stress the role of chance or accident in history will be found to prevail," he wrote. "The view that examination results are a lottery will always be popular among those that have been placed in the third class."
Which puts the counterfactuals in their place with donnish snippiness, but also misses the point that - in literature at least - we far more frequently imagine ourselves having failed the exam completely, rather than having taken a starred first.
Some alternative histories, it's true, exist to make the point that it wouldn't really have mattered which which way things went (alternative histories are naturally attracted to either/or events, such as battles and elections and infidelities). Shriver's book is one such, and Chabon's novel also conveys a similar sense of fatalism. "Strange times to be a Jew" is the phrase that echoes through it - with a wry implication that, whichever way the dice of history landed, the same thing would have been true. Others exist to imaginatively test moral qualities that went untested - as Sheers' book does, alerting you by its title - Resistance - to the big what-if of the Second World War: What did you do under occupation, Daddy?
What unites all of them, though, is the seduction of the untravelled path, whether arduous or smooth. And that seduction takes its force from our instinctive sense that the present, having not been avoided, is inevitable. Whether such books are set in the past, as Sheers' is, or the present, like Chabon's - they depend on the solidity of history as we know it for their shimmer of strangeness. And in that they oddly reinforce our complacency about the present rather than disturb it. Because the truth is that our present is always an alternative history from at least one perspective - that of the past.
This was brought home to me - at a relatively trivial level - by walking round the refurbished Royal Festival Hall last week. What, I found myself thinking, would Herbert Morrison have made of this enterprise? It's fiercely loyal to his vision of democratic access to the masses on one level but it also carves space out of the People's Palace for the exclusive entertainment of corporate sponsors and the provision of shopping opportunities. What would he have made of a world in which culture and retail were so intimately knitted together, having dreamt of one in which the state would bring art to the masses? How enticingly strange, if you think about it, that it should have turned out like this.Reuse content