My new novel has a contemporary setting, and I’ve had several kind notes from readers saying that they’re glad to see me turn away from historical fiction. I’m grateful for their support, but surprised that the label makes a difference to readers. Well, someone said, historical fiction’s a cop-out, it’s not relevant.

Relevant, I wonder, to what? To birth and love and death? To tragedy and happy endings, to the revolutionary ambitions of youth and the quietism of age? If I want to comment on the latest political developments, a novel, which takes a couple of years to write and usually another year to be edited and published, isn’t the obvious medium, and a novel of interest only in the month of publication isn’t much of an achievement for three years’ work.

Whenever a writer sets a work, the concerns of the day will shape the writing: Walter Scott’s “historical fiction” is all about nation-building and the logic of empire. Victorian medievalism fetishised rural life and artisanal craft as urban industrialism took over the landscape. Hilary Mantel shows us England defining itself in opposition to Catholic Europe and identifying a new basis of power. Even if I wanted to – I don’t – I couldn’t write a 19th-century novel, only a 21st-century novel with a 19th-century setting.

At its best, historical fiction is the invention of tradition at a moment of need. In my last two books, I was sketching Britain before the Welfare State, a country where life expectancy for the urban poor was in the low 20s while for the rural rich it was nearer 70. A country where manual labourers were often illiterate and innumerate, and only wealthy men had the vote. I was telling a story about some of the people who began the process of change that took its apparently final form in the second half of the last century with the establishment of the NHS, free primary and secondary education and votes for almost all adults.

I was fascinated by the kinds of lives lived by those who devoted themselves to changing a violently unjust nation into a better and fairer place for all. I wanted to show my readers that we have turned this country around before, have cleaned up the air so that urban children can breathe safely, have invented new laws and new crimes to protect children from sexual violence, have opened up education to people whose parents had no opportunities and offered healthcare to people who couldn’t pay. Here, I am saying, here is a story about people who did these things, here is an idea about the price they paid, about the human work we are throwing away as we demolish our inheritance. Irrelevant?

It’s true to some extent that all histories are fictions and all fictions are histories, but that doesn’t mean that history and fiction are the same thing. Histories are fictions because the reality of lived experience is fleeting, memory fallible and many of what later seem to have been the important things were not written down at the time. Fictions are histories because however experimental your form or unusual the narrative tense, the plot of a novel is over before you read it. The ending is there, in your right hand or stored in some electronic memory. It is over, which is one of the reasons for reading: to receive an ending of the sort unavailable in real life.

Nevertheless, history has ethics. We expect it to be true. “Rewriting history” can be a serious charge, although it is also the life work of some novelists. Fiction has a different kind of ethics, not to be true – or at least not verifiable – but to make sense, to offer some kind of narrative, perhaps even a moral; to let the reader see the world through other eyes. The ethics of fiction are always about the work of imagination, about the human ability to imagine what it might be like if things were different, and what it is like for other people for whom things are different.

Historical fiction, then, is able to imagine the stories missing from popular history. We all know that history is written by the survivors, the winners and the people with pens and paper and the time and training to write down their ideas. That’s why we end up with “Black History Month” and courses in “Women’s History”, not because black people and women are somehow not part of mainstream history (though it can feel like that), but because marginalised voices need a different kind of listening. It’s probably as well that most of our predecessors left no record of their thoughts – the historians of the internet age are going to have an unenviable task – but all those silences can become rather loud once you start thinking about them.

The narrator of The Tidal Zone is the descendant of refugees, and when his own unremarkable daily routines are suddenly disrupted he finds himself drawn to the untold stories of his parents and grandparents, finds himself telling lost and unwritten histories while the path of his own life falls away beneath his feet. We need stories, narratives for navigation, but we also need to know that stories can be dangerous in real life. Nationalism is a story, a myth to which European history offers a sober answer. Revolutions are fuelled by narrative. I am interested in rewriting history to make more difficult stories, to pull against the dominant narratives of my time and to insist, always, that there have always been other ways of doing things, other ways of understanding and moving through the world.

Sarah Moss is the author of The Tidal Zone, published by Granta Books this month