A genuinely poetic exploration of how divisions of the self could mirror the operation of a true artificial intelligence.

Blending psychology, mathematics and philosophy, this beautiful novel looks at the life and fate of World War 2 code-breaker Alec Pryor, a gay man who is chemically castrated and, it is hinted, commits suicide. It’s significant that he is not named Alan Turing, as that’s who he is clearly based on, because the novel explores the idea of reflections, specifically tessellated patterns of meaning – be they the interactions of variables in an equation, or the way a mirror’s image is different to the reality. Pryor is one such: a reflection of Turing who is part-fictional and part-real. Images recur like sequences of code: fairgrounds with their opposing attractions of mechanical organisation and the promise of abandon, or apples scrumped with a lover reappearing as tropes in a fairy tale. The images are the same, but everything about them is different.

As the chemicals take hold, Pryor, whose name hints at temporal realignment, experiences visits from a man in the mirror who is trying to communicate with him. This may be the future Pryor, or some digital fragment of him trying to gain an understanding of its heritage. The novel is thus a time travel as well as an AI novel, and conveys a reality-shifting sense of how intelligence is formed by disparate identities negotiating a shared understanding of what is truly going on. It has a freewheeling approach to time and space, yet delivers a satisfying twist at the end.

The novel demands and rewards close reading, both for the bracing but gently expressed big ideas, and also the glorious, evocative language. At times it’s a hard read, not just because of the complexity but also because of how angry it makes you feel. My other two favourite recent AI novels – Everything About You and I Still Dream – deal with human emotions, and the overwhelming climactic feeling is the kind of warmth that comes from both human grief and love. Murmur gives a hint of machine emotions, and what those might be like. Similarly confusing as human ones, there is a suggestion that empathy is a construct, that such an idea is no bad thing, but that without sufficient understanding it can lead to the same kind atrocity that befalls Pryor. The murmur under the surface thus often feels like a current of rage.