In her keynote lecture for a conference on ‘The Muse and the Market’ in 2015 Aminatta Forna mounted a powerful advocacy for the political novel, challenging the assumption that politics or ‘subject’ undermines literary aesthetic. ‘A political novel can fail as a work of art as much as any other novel,’ she argued, ‘but the fact that it is political does not sentence it to failure.’

Her own approach to fiction is something like Paul Klee’s approach to his art: where Klee talked of taking a line for a walk, she says: ‘When I write a novel it is like taking a thought for a walk.’ In Happiness, Forna’s fourth novel, the thought up for consideration is that in the West many people’s lives are so sheltered they have become terrified of suffering, pathologising even ordinary loss or grief as trauma. Perhaps this desire for safety, she speculates, has also led to a fear of incomers — a fear expressed in blindness to the many migrants at work across the city, or in anxiety when confronted with wild creatures in urban territory, with the sudden ‘opalescent eye shine of an animal’ in the road.

These fears are scrutinised, and countered, in Happiness by Attila, a debonair Ghanaian psychiatrist visiting London for a conference on PTSD, and Jean, an American wildlife biologist in the capital to study urban foxes. They are both adapting to life after recent losses: his incurred by the death of a beloved wife, hers by a divorce that has separated her from her son.

The two collide on Waterloo Bridge one winter evening and then again in a nearby underpass when they intervene to stop a white beggar from being attacked. These collisions are followed by many more, to the point where London, the novel’s third major character, is depicted as a place that continually puts one kind of person, or animal, in the path of another: a Bosnian street performer opens the door for a fox meandering through the National Theatre; a Sierra Leonean traffic warden notices a boy loitering alone by the Thames; and a flock of parakeets makes a home in Nunhead Cemetery, aggravating the local council but delighting the joggers and dog-walkers.

Not all encounters are welcome or convivial: one frightened woman crosses the road to avoid coming face to face with a recently bereaved acquaintance. Against such antipathy, Forna proposes that rather than fencing off our lives in fantasy (‘prelapsarian gardens’), the best hope for survival, and indeed for happiness, is to cultivate ‘a sense of something that goes beyond ourselves’.

Once worlds collide it takes curiosity, empathy and will to draw people together. When Attila tells Jean about his runaway nephew, caught up in an immigration sting, she realises she can help him, having knowledge of the city from tracking foxes. She also has access to a network of people who assist in monitoring the foxes’ movements: migrant road-sweepers, traffic wardens and security guards, all with expertise in London’s street culture. And they volunteer to search for the boy. The reason they are willing to help is their sense of solidarity, something echoed in the silent nods of acknowledgment that pass between Attila and other black people as they make their way through the city.

The correlation of Forna’s idea that some in the West have become insular and enclosed, is that those most exposed to suffering — having learnt from it — may have developed greater emotional resources. In her rather Nietzschean novel, which emphasises knowledge, tenacity and resilience over victimhood, this is demonstrated time and again. Which is not to say that Forna is an idealist. Happiness is an outward looking book, yet in passages that punctuate the London story, set in Bosnia, Sierra Leone and Iraq, the ravaged places where Attila has worked with civilian and combatant victims of war, there is no doubting the suffering that human beings inflict upon one another, and upon other species.

Here, Forna thinks deeply about our responsibilities and how we can all get along. Attila tells Jean: ‘Some in my profession believe animal cruelty is an early indicator of worse to come’; while she points out that foxes have moved into cities not, as widely held, because we stopped hunting them in the country, but because fast food means ‘the sidewalks have turned into “all you can eat buffets”’. Where Jean is fascinated by the culture of the natural world and inter-species relationships, Attila responds to the horror he’s witnessed by cultivating his love of food, dance and language, conversing with a colleague in Esperanto, the dreamed-up speech of international fellowship.

The novel ends with Attila’s own conference keynote lecture in which he calls on the work of Frantz Fanon, R.D. Laing and the anti-psychiatry movement, to argue that ‘trauma does not equal destiny’. He also returns to his love of Robert Graves, who went back to the trenches, deciding ‘he preferred the suffering of war to the insufferability of civilisation’. Goodbye to All That might well have provided an alternative title to Forna’s piercingly intelligent and interrogative novel which, like the earlier book, registers tectonic shifts taking place in the world and provokes us to think anew about war, and what we take for peace and happiness.