I published my first novel, Cold Earth, which is set during an epidemic, on the day the World Health Organization declared avian flu to be a pandemic. I hadn’t, of course, predicted that particular disease, but the story of pestilence, like those of war and famine, is always in the offing, and you don’t have to know much to understand that humans’ destruction of animal habitats keeps us at constant risk of zoonotic viruses. The story was there before the disease had a name.

My seventh novel, Summerwater, was written before Covid-19. I was surprised by how many people asked me if I had to make last-minute changes, asked if it would be impossible or even irresponsible to promote a book in which people go dancing or share food or hug now those pleasures are forbidden. It didn’t occur to me to want to change anything. After all, the novels of the 1930s are more, not less, precious for their innocence of what is to come, for their glamorous journeys and lavish parties, and also for their dawning horror. The stories of that growing dismay are important as well as beautiful: what did readers and writers see and what could they not imagine? How does literature meet, or fail to recognise, war (or plague or famine)? Novels speak of their moment but the good ones don’t go off.

There’s no pestilence in Summerwater, but there is a kind of lockdown. It’s set in a holiday park in Scotland on one wet midsummer day, and follows voices from six households. They could leave, but the point of being there is remoteness, so they don’t. Some go out in the rain – a woman running along the shore at dawn, a teenager escaping his family in his kayak, children sent out to play by an irritated mother – but no one goes far and most stay inside, watching the rain and each other, making their own fun and resenting or envying the single mother who somehow manages to have loud parties most nights.

I had not foreseen lockdown. I was thinking of post-Brexit Britain, a country of apparently similar people with a great deal in common, no longer able to leave easily, and so divided and distrustful that they can barely communicate across gradations of class, generation and political allegiance, absorbed in judging and raging against each other while the real crisis, which is climate change, gathers speed in the background.

There are small but important pleasures of love, sex, food and exercise, but the joys are rarely shared. Couples give or steal from each other time to go for a run, to read a book or take a bath, and the pair having sex are not together in their imaginations. Children’s needs are endless and teenagers want both attention and escape. Family holidays are often a benign kind of lockdown. It wasn’t hard to imagine.

One of Summerwater’s central questions is whether a group of similar households on different sides of ideological divides is capable of responding as a community to a crisis. I invented the crisis and it didn’t, this time, take medical form, but the question seems no less urgent during Covid-19 than it did when I was writing the book last year. In all our fragmentation and fury, do we still recognise enough common humanity to save each other? By “we”, I mean those who find themselves in the same place, in accidental physical proximity: the people you rely on to notice if your house is on fire, to hear you scream, to look after your parcel or jump-start your car, however they vote; the people whose music and social life and taste in exterior decor you can’t ignore. (As I write I hear the woman next door laughing with a friend in her garden, someone a few doors down playing the flute rather well, builders renovating the house over the road, a car alarm we’re all ignoring.) Neighbours.

The stories of neighbours took on new urgency in lockdown. My family was lucky: so far as I know no one counted our walks, runs, bike rides and grocery shopping. My household, at low risk, did some shopping for those who didn’t want to go out. I chatted to our nonagenarian neighbour who continued to do her own shopping and to take the newspaper round to her friend for the crossword: ill-advised, of course, but I was cheered to see someone whose desire for company outweighed terror. (And the fact that I hesitate to write this, that I fear that even a remembered smile will get me into trouble, is part of the point.)

Friends had more disturbing experiences. A doctor came home to a note telling him he had “been reported” for taking a bike ride of more than an hour one evening after a long shift in a “hot” coronavirus clinic. Another friend was reported to the police for allowing her brother to sit with her in her garden in the days after his wife died. We all know the stories, and we all know better stories too: there was a moment there when English neighbourliness could go either way, and those are the most interesting moments, the ones you want to write about. When your neighbours have a party, do you call the police or take a bottle and join in? As an early riser I was always inclined to anger, but lockdown has changed me, and just as well since the neighbours now socialise, in accordance with local guidelines, in their gardens. What better sound than the people we live with having fun?

In the UK and the US – perhaps less in Ireland where I live now – the coronavirus debate seems to be taking the same binary form as all the other problems requiring a collective solution. One tribe wants everyone indefinitely locked up for their own good, and anyone suggesting any other way forward – murmuring about education or cancer treatment or even fun – is a mask-refusing, Trump-supporting eugenicist. The mask-refusing, Trump-supporting eugenicists are willing to die for freedom, the problem being that most of those in practice required to do the dying don’t have much freedom.

We’re going to need some better stories, ones growing in the ground between impossible truths: lockdown is our only solution but lockdown also destroys children’s futures and the minds, relationships and health of all but the luckiest and strongest (and the economy). I am constantly surprised by the formation of this debate as health versus wealth, or lives versus money: what about education, friendship, sport, art; the fundamental human needs to be together, to be curious, to make things; our best hopes for the future? How, if at all, do we here and now value what is difficult to count? We can’t live indefinitely between the fear of contagion and the fear of confinement, because even the most rational fear wears out and fades. Horror stories and post-apocalyptic fiction have endings like all the other stories, but in real life we’re still around, facing another day. The ending of that first novel was difficult for exactly this reason: we learn to live with the intolerable, and to tolerate it, and then what story should we tell?

I write with attention to daily life because that is how we experience the world almost all the time. When bombs are falling, babies still need milk. During a pandemic we worry as much about toilet paper as about dying. People in refugee camps long for hot showers as well as liberation, and the laundry and the cooking and the washing up are with us as long as we are with our bodies. We live in moments, not eras, and so I write in moments and let the eras take care of themselves.

• Summerwater is published by Picador (£14.99). To order a copy go to guardianbookshop.com. Delivery charges may apply.