Most people think that knowledge is solid and unchanging, just waiting to be accessed from the libraries of the world. It isn’t.

What we call ‘knowledge’ is actually no more than our best guess. Take Fred Hoyle’s steady state theory of the universe. Later evidence proved him wrong and gave us the Big Bang hypothesis. But then, that too could be sunk by new evidence arriving tomorrow.

When COVID-19 broke out, nobody knew whether it was a terrifying killer, or a mere nuisance. Governments pursued different strategies based on different guesses. Imperial College London, for example, figured that a third of Britain’s population were already infected and 250,000 people could die. Then Oxford University concluded that the virus was indeed common, but so mild that the healthcare system could cope. Then a Stanford University study—and a second one from Imperial—calculated that the virus was even less deadly than seasonal flu.

Science done at speed, on rapidly changing events, is always bad science. Emerging evidence will improve it.

BUT: that evidence itself will still be speculative, questionable, maybe biased, mistaken or downright wrong.

Still, if you think the medics have little to go on, spare a thought for the economists trying to determine the full effects of the lockdown. They know even less.