The Ghost Map: The Story of London's Most Terrifying Epidemic--and How It Changed Science, Cities, and the Modern World

by Steven Johnson

All nucleated organisms generate excess calcium as a waste product. Since at least the Cambrian times, organisms have accumulated those calcium reserves, and put them to good use: building shells, teeth, skeletons. Your ability to walk upright is due to evolution’s knack for recycling its toxic waste.

The fear of death’s contamination can sometimes last for centuries.

Bacteria and viruses evolve at much faster rates than humans do, for several reasons.

In a sense, the Industrial Revolution would have never happened if two distinct forms of energy had not been separated from the earth: coal and commoners.

The explosion of tea drinking in the late 1700s was, from the bacteria’s point of view, a microbial holocaust.

Whenever smart people cling to an outlandishly incorrect idea despite substantial evidence to the contrary, something interesting is at work. In the case of miasma, that something involves a convergence of multiple forces, all coming together to prop up a theory that should have died out decades before.

“overdetermination.” It was theory that drew its persuasive power not from any single fact but rather from its location at the intersection of so many separate but compatible elements,

the path of science works within regimes of agreement and convention, and history is littered with past regimes that were overthrown.

cholera was ingested, not inhaled.

The poor were dying in disproportionate numbers not because they suffered from moral failings. They were dying because they were being poisoned.

But it was not divine providence that drove the process. It was density.

“confirmation bias”: the tendency to force new information to fit one’s preconceptions about the world.

the confirmation bias toward miasma was so strong that it literally blinded them to the patterns that Snow and Whitehead perceived so clearly—blinded

The map is a brilliant work of information design and epidemiology, no doubt. But it is also an emblem of a certain kind of community—the densely intertwined lives of a metropolitan neighborhood—an emblem that, paradoxically, was made possible by a savage attack on that community.

Broad Street should be understood not just as the triumph of rogue science, but also, and just as important, as the triumph of a certain mode of engaged amateurism.