In 1854, London was devastated by the mysterious spread of cholera and the finest scientific minds of the time were unable to diagnose (let alone stop) the disease which they theorised was an invisible ‘miasma’, a toxic vapour that brought death to all it touched.
But that made no sense to a young doctor who’d carefully charted the exact location of every fatality and who’d noticed the theory didn’t fit the reality. Why, for example, would a vapour wipe out one side of a narrow lane while completely ignoring homes on the other? Why would it kill an entire home but spare the people next door?
John Snow asked one of most important questions in the problem solver’s vocabulary: who wasn’t affected, and why? What made the survivors different? He quickly realised it wasn’t diet, fitness, socioeconomics, religion or vocation … everyone in that part of Soho was in the same boat.
But not everyone got their water from the same place. Remember this was before the Golden Age of Plumbing, a time when you had to visit the local water pump to do laundry, have a bath or just put the kettle on.
Everyone who got their water from the pump in Broad Street got cholera, and anyone who didn’t … didn’t. This was no miasma, this was a disease you got from bad water. Snow had isolated the problem by asking what it wasn’t. Unable to get official support from local authorities, Snow hired a local workman to disable the Broad Street pump and within weeks cholera had disappeared from Soho.
Want to solve a problem? Find out where and who and what and when it isn’t. Because sometimes that difference … can really be the difference.