The lovely title of this book comes from the philosopher David Hume. The question he posed was this: if a man grew up familiar with every shade of blue but one, would he be able to recognise the hue in a chart of blues, or would it register only as a blank? In other words, can the intellect supply information, or may we know things only through the senses?
Dwelling too long on this sort of problem famously sends people mad. Hume himself suffered a breakdown, after which he sensibly made it his business to get out more. In this novel, two of the three people central to the story have experienced, or are experiencing, psychiatric problems, while another important but peripheral character spends the duration locked in a loony bin. Of these first, one is a philosopher, the other a Frenchman engaged in translating Hume’s essays.
This is rarefied stuff. The people here spend their time talking about Socrates and the impossibility of happiness, or discussing their vocations as artists, philosophers or highbrow translators. The book is billed as a philosophical adventure, which made me nervous. If the premise of the novel is that something visible can fail to be noticed, did this mean that I was missing something? Possibly something crucial; possibly, indeed, the whole point of the story?
As befits a work so closely concerned with Hume, the book is set in Edinburgh (and in 18th-century buildings, at that), with a spell in France. The translator arrives from Paris and soon befriends the philosopher and his wife, a much younger artist. The philosopher is in an agitated state because of his perceived marital troubles: soon he has confided all his woes to the younger man. The translator is a fastidious and lonely type, whose ability to become so close to this couple with such speed is not always believable.
This slight cavil aside, these are well- drawn characters and their story becomes ever more absorbing. Jennie Erdal is a writer of great precision, delicacy and control. By the time I was halfway through, I decided to stop fretting about whether I was missing some crucial clue and simply enjoy the read.
Gradually, ideas gave way to feelings, some of them primitive. The quiet academic surface conceals churning depths where monsters lurk: stillborn babies preserved in glass jars, ugly skin complaints, madness and remorse. It is the literary equivalent of crossing from the serene order of Edinburgh’s New Town into the dark and dangerous labyrinth of the Old Town. Perhaps this is deliberate, a nod in the direction of James Hogg and Robert Louis Stephenson. Be that as it may, things become ever stranger and more unsettling.
The novel ends on a lighter note. In the end, the missing shade of blue turns out to be a metaphor for love: not so hard to guess at, after all. This is a writer of rare assurance and intelligence. Admirers of Iris Murdoch will feel very much at home here. Jennie Erdal is a name to watch out for.