ANYONE WHO HAS worked in science for the past fifty years, as I have, has experienced many changes in the way a scientist looks at the world. The growing interest in wicked problems leads to the question: are the moves to tackle such problems a fresh way of understanding how the world works, or just another passing fancy? And this leads to more questions: do we really have wicked problems in the first place – that is, problems so diabolical that they cannot be resolved by anything that we already know how to do? Are the risks to our future – climate change and nuclear warfare, for instance – any worse for today’s citizens than they seemed to those who prayed for escape from the Black Death and the lethal crossbow?

In the seventeenth century the so-called Enlightenment promised to change the way we lived in the world, and largely delivered on that promise. The resultant hygiene revolution controlled epidemics of cholera and smallpox, which in turn allowed people to live together safely in large cities. A technological revolution harnessed steam, fossil fuels and nuclear fission, providing the energy sources for twenty-first-century global flows of people, finance and information.