Anna and Ryan are the perfect couple. They have scientific proof. A few years ago, the pair took part in a new test. They each tore off a fingernail and put it in a machine that assesses their compatibility. Anna and Ryan scored a perfect 100%.¹

Yet Anna is restless. Her life with Ryan has become stale. She takes a job at the Love Institute, conducting experiments to assess other couples. And she begins to develop feelings for the doctor Amir, who has never himself managed to find his 100% match. Maybe her own relationship is not so perfect after all?

This is the premise of Fingernails, a new film by Greek director Christos Nikou. It has met mixed reviews.² American critic Robert Daniels hailed it "a banquet of slow cinema", while The Guardian's Charles Bramesco called it "a long, fitfully amusing walk down a short road".

Even the naysayersA naysayer is someone who objects to something or says a project is likely to fail. admit that it has a fascinating central concept. What if we had a machine that could tell couples if they were in love? Would people decide to use it? How would it change our lives?

It is the stuff of science fiction. But it may not be so far away. Dating apps already assess how compatible people are based on their user history and conversations. As AIA computer programme that has been designed to think.  expert Yuliya Sychikova writes: "companies tune the algorithms to account for personality traits, music taste, beliefs, attitude and much more."

The Fingernails machine would be an enormous advance on even this. As well as telling people that they are on the right track, it could stop others from staying in ill-fitting relationships.

There are thousands of divorces and break-ups each year.³ The machine could blow all this away by splitting them up quickly. In Henry James' Portrait of a Lady, Isabel Archer becomes deeply unhappy after marrying the selfish Gilbert Osmond. A fingernail test might have spared her the pain.

It could also help people come to terms with unrequited love. If someone is in love with you but the feeling is not returned, take the test with them to clear the air. In Thomas HardyAn English novelist and poet.'s Far From the Madding Crowd, William Boldwood becomes dangerously obsessed with Bathsheba Everdene.⁴ Machine-generated proof could have helped him move on.

Yet there are downsides to being informed. Love is not always at first sight. People change. Feelings develop. When Elizabeth Bennet meets Mr. Darcy in Jane AustenAn English novelist most famous for writing Pride and Prejudice.'s Pride and Prejudice, they form an instant dislike. They would have scored 0%. But by the novel's end, they realise they are a perfect match. The machine might have cut them off before they began.

The idea of reducing love to a number is antitheticalSomething that is antithetical to something else is the opposite of it and is unable to exist with it. to love's strangeness. PetrarchA scholar and poet of the early Italian Renaissance. spent a career writing love poems to Laura, who he saw only once.⁵ As Shirley Li writes in The Atlantic: "Love is a fragile, intangible bundle of contradictions - something at once beautiful and terrible, invigorating and agonising, joyful and melancholyA feeling of sadness.."

Love and life are both about these experiences. The machine might spare people unhappiness. But it might take much more away.

Yes: The fingernail machine is just the start. Imagine if we had devices that could detect all our emotions and help us manage them. Machines can improve our lives by teaching us more about ourselves.

No: The machine is the start of a slippery slope. What if we began assigning ratings to people's personalities and abilities? It might lead to a world where our lives are controlled by numbers.

Or... Love is not a number. It is not a constant state but a voyage, ebbing and flowing over time, mixing the good and the bad. This is its beauty. A machine-generated score misses the point completely.