May the odds be ever in your favour? The politics of prognosis

When I was three years old, I was told that my brother Jason had a 95 per cent chance of dying before he was one. He was born with cerebral palsy, muscular dystrophy and other conditions that made the doctors believe he’d have a dramatically shortened life expectancy. Year after year, my brother outlived this fateful prediction – but its spectre haunted my family and spurred us on in the search for knowledge about Jason’s diagnoses.

All humans naturally desire knowledge, as Aristotle proclaims in the opening line of the Metaphysics. In our present age, one is tempted to add, especially about our health and the health of our loved ones. From Fitbits to WebMD to 23andMe, we commune, conspire and conduct our lives in a thicket of diagnostic and prognostic bioinformation. But, as philosophers from Aristotle to Zhuangzi have insisted, information is meaningless until it is interpreted – and interpretation is always a fraught and messy business.

Jason’s ‘95 per cent’ wasn’t just an indifferent number. My brother’s life is evidence of the politics of probability...