Snow in London

How do you see what you cannot see?

As I walked the streets of London this morning I stumbled across ground zero in one of the great epidemiological debates of history, as Europe battled a cholera pandemic that lasted from 1846-1860.

Shivering in Broadwick Street in Soho, I imagined the scene 150 years ago. Stand with me, if you will, in the misery of cramped housing and crime, poverty and lack of sanitation. The heat of summer lays like an oppressive blanket in the narrow, crowded streets, while the acrid smoke of cooking fires rasps in your throat and the threat of cholera stalks the streets. It's understandable to reflexively reach for those twenty-first century germ barriers, the mask and the sanitiser.

And then, temporary relief looms. A water pump. The Broad (now Broadwick) Street water pump, lifting water from a spring that is claimed to hold the best water in London. Who would not join the shuffling queue, to drink their fill.

The Broad Street water pump. Note the missing handle. Photo by author

London, along with much of Europe, experienced regular unexplained cholera outbreaks, emerging as if from nowhere and decimating populations. And the poor in Soho, living in awful conditions—several people to a small room, inadequate diet and complete lack of air circulation—were particularly vulnerable. When cholera struck they were on the front line, unable to find refuge elsewhere. Those who could leave fled to the country, often taking with them jugs of water from the Broad Street pump.

Unwittingly transporting death.

For cholera was not airborne, but waterborne, a point of view that the scientific community, in the guise of the Cholera Commission, refused to countenance. For they followed the science. Clearly if an infected person moved to another community, and the people with whom they came in contact became ill, the cause was the coughing and sneezing.

Follow the science or follow the facts?

But Dr John Snow disagreed. He believed cholera was waterborne. And further, that it came in particular from the Broad Street pump. John Snow had a different mental model. He was open to new ideas and new perspectives. He did not simply go with popular opinion. John Snow chose not to follow the science, and became an outcast from the academy.

Portrait of John Snow, at the hotel named after him in Broadwick street. Photo by Author

Steven Johnson takes up the story in his wonderful book The Ghost Map, demonstrating how mental models create not just bias but entire blind spots: an inability to see alternatives. His meticulous work reads like a detective novel as Snow races to confirm his hypothesis before another outbreak lays siege to London. Johnson does a wonderful substack on innovation at Adjacent Possible.

Johnson explains that the accepted scientific explanation for the spread of cholera was known as the miasma theory, which held that cholera was an airborne disease. Seeing how the disease spread rapidly among people living in packed squalid conditions only confirmed this view. As long as the miasma theory held, then any cure would focus on improving air quality and circulation, and, where possible, creating space between people. (We decided to call that social distancing).

John Snow, however, argued that cholera was waterborne. During the 1854 epidemic he slowly and painstakingly assembled data—testing water from different pumps, discovering the habits of victims from interviews with surviving relatives, mapping the times and locations where people contracted the illness. His rigorous research indicated that cholera was indeed waterborne, and that the current outbreak was emanating from the Broad Street pump. The pump handle was immediately removed, denying access to the water, and the number of cases rapidly declined.

However, Snow realised the outbreak may have been near exhaustion, and so his theory was not sufficiently proven. The ultimate proof would be someone in a remote location contracting cholera after drinking water sourced from Broad Street.

Snow took his findings to the Cholera Commission, where the learned doctors agreed that a remote illness would support Snow's findings.

Snow waited patiently, scanning his phone everyday for the latest epidemic statistics. (Not really, he had to do it the hard way, talking to doctors, relatives, friends. Waiting. Waiting.)

none so blind as those who will not see

The journey from Soho to Hampstead takes a bit under half an hour on the tube, or just an hour and a half for a brisk walk. It's not far for us, although in Snow's time Hampstead may as well have been in Scotland. It was a whole different world.

When Susannah Eley died in Hampstead, after drinking water brought to her from the Broad Street well, it seemed Snow had his conclusive proof.

However, existing mental models blinded the medical profession to reality.

The Cholera Commission used Eley's death to prove their theory of an airborne disease, claiming the infected atmosphere in Soho had poisoned the water. How extraordinary.

While the commission dithered and debated people died.

This tendency to become mired in the prevailing model—to go along with the crowd as it were—is not limited to 19th century England.

We are also blinded by our field of expertise. Snow’s experience reveals so clearly how our view of what is relevant is coloured by our mental models. In the face of Snow’s compelling evidence that cholera was waterborne, the General Board of Health, and influential media commentators, refused to be swayed, so firmly were they wedded to the miasma theory. We see here the danger of too readily accepting what is immediately presented and unquestioned as being the true state of affairs.

Seek first to understand

The same thing happens in business, when we look at people, events and circumstances through the lens of our expertise. Operating from our field of expertise explains why the finance director tends to search for and give added weight to financial data, having less understanding of (say) production or supply chain data, while the director of human resources will focus on data relating to people, performance and culture.

This explains why specialisation can be an obstacle to being an effective CEO, and why functional or business silos can be an obstacle to organisational growth and performance. Both encourage lenses which unknowingly and unintentionally filter out other important information. They cause us to see what we have been trained to see, to explain everything through that lens, and to be blind to alternative information and explanations.

As we look across uncertain and unknown horizons, trying to solve confronting problems which appear to risk our future, our greatest risk is that we ask the wrong questions and close ourselves off to unpopular answers. Long before Alfred Korzybski proclaimed ‘the map is not the territory’, Snow built an actual map of the territory against which he could test his model. He implicitly understood that one cannot work without the other. We need both meaning and measure. Confusing seeing with meaning—poor air means miasma lurks—is one of the biggest mistakes leaders and policy makers can make.

Hence a key human capability is not simply to become aware of our blind spots and biases (and that is a whole ‘nother conversation for how you can do that. How can you see what you cannot see?)

A key capability is simply to accept that others have valid perspectives, and may well be a yin to your yang. Or, more critically, may be a light to your ignorance.

One of Stephen Covey's Seven habits for highly effective living (another great book) is 'seek first to understand before being understood'. It's worth taking the time to do so.

Otherwise you may inadvertently drink from a poisoned well.

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I explore mental models, and how an organisation can become not just a learning organisation, but a thinking organisation, in a paper which you can download here: