Look at the graph reproduced on this page. It shows the material standard of living of the average English person over a span of eight centuries beginning in 1200. In 1800 the average English person was literally no better off, in food, clothing, and shelter, than in 1200. Although there had been ups and downs, there was no long-term improvement. Nobody would have been talking about “growth.”
Then, in the early 1800s, not exactly suddenly but quite rapidly on this long time scale, it all changed. Less than two hundred years later, the previously stagnant standard of living had multiplied by six or more. That was the Industrial Revolution. Nothing closer to a Big Bang had occurred in human history. Now nobody talks about anything but growth in standard of living. This is not a new observation: the broad facts had long been noticed and discussed by Paul Bairoch, Carlo Cipolla, and other economic historians.
According to Gregory Clark, who teaches economic history at the University of California at Davis, this picture could be extended to cover the whole world and the thousands of years since the beginnings of settled agriculture. He even catches the reader’s attention with a graph looking just like this one, but extending from 1000 BCE to the present. That graph, as far as one can tell, is largely made up. Only a handful of scattered and crude estimates of income per person exists for ancient times. On the other hand, Clark is very good at piecing together figures from here and there, including those from isolated groups of hunter-gatherers alive today. He makes a plausible case for the basic pattern: for thousands of years before the Industrial Revolution, there was essentially no sustained improvement in mankind’s general material standard of living, nor was there much variation from place to place around the world. The Industrial Revolution made all the difference.
It is worth emphasizing that this is all about material standards, not cultural evolution or the “level of civilization.” Shakespeare, Purcell, and Newton had done their work in England long before 1780 or 1800. But ordinary people still lived in hovels and wore rags.
Accepting this big picture, Clark is after deep answers. He proposes to explain why the stagnation lasted so long, why it ended with the close of the eighteenth century and not much earlier or later, why the Industrial Revolution occurred first in England and not in China or India or somewhere else, and why some parts of the world, such as Europe and the United States, continued to improve standards of living long after the Industrial Revolution, while other parts of the world, including Africa, stagnated or deteriorated. And he attempts to do all this not encyclopedically but by applying a neat, clean theory.
There are many reasons to wonder what it could possibly mean to figure out the “cause” of a unique historical event. Any large-scale historical event surely has many “causes,” some more important than others. How …