The folly of data mining

GARY SMITH

COFFEE was wildly popular in Sweden in the 17th century — and also illegal. King Gustav III believed that it was a slow poison and devised a clever experiment to prove it. He commuted the sentences of murderous twin brothers who were waiting to be beheaded, on one condition: One brother had to drink three pots of coffee every day while the other drank three pots of tea. The early death of the coffee-drinker would prove that coffee was poison.

It turned out that the coffee-drinking twin outlived the tea drinker, but it wasn’t until the 1820s that Swedes were finally legally permitted to do what they had been doing all along — drink coffee, lots of coffee.