Among the blizzard of acronyms we learned during the pandemic was SAGE, short for Scientific Advisory Group for Emergencies. A subgroup within SAGE with a less reassuring acronym was SPI-M, or the Scientific Pandemic Infections Group on Modelling. Adam Kucharski was a member of that group and his work there inspired this book, which looks at our search for answers in an uncertain world.

Professor Kucharski is a mathematician by training, so his starting point is the kind of proof made famous by the Greek mathematician Euclid. Begin with some simple definitions and self-evident axioms, then proceed by logical steps to a conclusion. This works well for geometry and for centuries was seen as the paradigm of proof. The 17th-century Dutch philosopher Baruch Spinoza used ‘geometrical demonstration’ to prove the existence of God, among other things.

There were attempts to apply the same thinking to legal systems and national constitutions. The hard part was agreeing what was ‘self-evident’. In 1854, Abraham Lincoln said supporting slavery was ‘to deny our national axioms’, but it was not until eleven years later that an amendment outlawing it was added