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 are we to know that a proposed explanation has not left out something important or insisted on the significance of something that is really extraneous? To put the question more generally, how can there be a test of a theory about a unique historical event? There is by definition no second experiment to provide a check, and some sort of check is needed.
Historians sometimes try to resolve this problem by imagining that the event at hand is really a member of a larger class of events. Students of “revolution” will think of the French “case” or the Russian “case” or the Iranian; students of war will speak of the Franco-Prussian “case” or the “case” of World War I. We do not have any trouble with “cases” of strep throat, although there are always some differences among them. Wars are not so straightforward. One has to decide whether the Franco-Prussian War and the Thirty Years’ War are really so similar in their etiology that a theory about the causes of one has to apply successfully to the other, or else be rejected.
When it comes to the Industrial Revolution, part of the premise is that it was a truly unique event, so that there is nothing to compare it with. Even if Germany had its own industrial revolution some decades later, it would not be comparable to the English one if only because the social and technological changes that figured importantly in England were already known and available for imitation or adaptation or rejection, not to mention the fact that England was already exporting industrial products.
It seems that there are two sorts of less satisfactory “tests” available for judging Clark’s—or anyone’s—answers to his key questions. First, any theory will have various building blocks, bits of intellectual machinery, some of which can be tested against a broader class of facts. Second, we simply have to judge whether the story he tells hangs together and passes the test of plausibility. In the background there is always the “null hypothesis” trial horse beloved of statisticians and econometricians and no one else. Suppose, they say, there was always a very small probability that an industrial revolution would occur in each century since the year one, in any one of ten eligible places. It was bound to happen somewhere in some century; heads just happened to come up for the first time in England in 1800 after 180 (eighteen centuries times ten places) consecutive appearances of tails. Any decent explanation has to beat that one.
Clark explains the long era of pre-industrial stagnation as a “Malthusian trap.” In other words, he interprets it as the working-out of the process analyzed by T.R. Malthus in his Essay on the Principle of Population (1798) and refined by the great classical economist David Ricardo, who published his Principles of Political Economy and Taxation in 1821. Other economic historians have come to the same conclusion, though you might not realize that from reading Clark’s text. He pursues the Malthus-Ricardo model with a great intensity and unusually broad empirical scope.
Here is how Malthus-Ricardo works. In any society at any time there is a reasonably well defined notion of “subsistence,” a level of income, essentially wages, just adequate to support a standard of living that will lead the average family to reproduce itself. Subsistence has a hard physiological basis in calories, necessary nutrients, protection from weather, and the like, but it can be modified by cultural factors, social norms, and customs. If wages happen to exceed subsistence for a while, because of good harvests or a reduction in the supply of labor through war or disease, normal mortality will decrease, fertility may rise, and the population will increase. But not for long: the pressure of a larger working population on a fixed supply of land and resources will force labor productivity and wages to fall. (That is the famous law of diminishing returns: the idea is that as more and more workers are squeezed onto the same area of land, at some point each additional worker will be able to add less output than his predecessor did, simply because he has a smaller share of the land to work with.)
This process cannot stop until wages are back to the subsistence level. The population will be bigger, but its members no better off than they were. If harvests then go back to normal, productivity and wages will fall below subsistence and the process just described will go into reverse: higher mortality will cause population to fall until productivity and wages return to the subsistence level and then stabilize.
This is a simple and powerful story, and it has just the implications needed to explain the grim preindustrial history. The key implication is that the material standard of living of any population is determined only by the level of subsistence. Incremental technological progress, which certainly took place in England—and elsewhere—between 1200 and 1780, does not seriously improve living standards; it just allows a larger population to be supported. Malthus thought about “prudential checks” to population—e.g., practicing abstinence—but wistfully. (The consequences of a large and rapid burst of technological progress—not part of Malthus’s story—may be different; and that will be important when we come to the Industrial Revolution itself.) Even more paradoxically, progress in health care and sanitation may mean that the subsistence wage falls, because now mortality can be contained with even less in the way of nutrition, clothing, and shelter. In principle, then, medical progress could lead to lower wages and poorer conditions of life in those other respects.
This Malthus-Ricardo trap can certainly account for the long failure of living standards to rise. Clark exploits it with a lot of interesting and useful circumstantial detail. Here is an example. The sustainable level of the subsistence wage and standard of living can be higher in one country than another if the first can maintain lower fertility (at any given wage) than the second; population will stabilize at a higher wage, more or less by definition. Clark notes that preindustrial England did in fact have a lower fertility rate than other parts of the world in roughly the same income class. The mechanism was not primarily individual contraception but rather social norms: people married later in life and there were larger numbers of spinsters. One could speculate why this was the case: perhaps it was a response to the custom of primogeniture. The origin is interesting; but the fact itself could obviously be important in shaping England’s response to the beginnings of the Industrial Revolution.
The coming of the Industrial Revolution has attracted more attention from economic historians than the prolonged preindustrial stagnation. Clark’s story has some things in common with other accounts, and some twists of its own. It is not always easy to distinguish between them because he is not exactly assiduous about crediting earlier work. I will try to identify the specifically Clarkian twists as they arise.
The Malthusian process works itself out slowly. The chain of causation from a rise in wages to decreased mortality and increased fertility, then from induced changes in population to changes in the supply of labor, and from the latter back to a fall in wages could take years or decades to complete itself. Now imagine what might happen if there is a series of major technological innovations. Productivity and wages may have time to rise by a lot; and they may keep rising even after population starts to increase, if the favorable effect of rising productivity from later innovations outweighs the depressing effect of higher labor supply.
But then new possibilities emerge. For instance the experience of rising incomes could encourage lower fertility, with an emphasis on fewer but better-educated children. This would figure in the theory as a drastic change in the social definition of “subsistence.” The point is that the dismal Malthusian prospect could be postponed, perhaps forever. Something like this did happen in the West. The so-called “demographic transition” to lower fertility is usually dated to later in the nineteenth century; but the birth rate in England actually started to fall in the 1840s. As Clark points out in an interesting discussion, there was undoubtedly more to the demographic transition than the simple mechanism of rising incomes.
I would like to thank my own personal economic historian, Barbara L. Solow, for help and advice.↩
I would like to thank my own personal economic historian, Barbara L. Solow, for help and advice.↩