One of the major reasons I enjoy having a blog is the many excellent comments that the readers make on various ideas I float here. Sometimes they make me change my views, sometimes they force me to explain things better, or clarify my own thinking on the subject. All of this happened as a result of exchange following the previous blog (The Rise of the West: Science and Ideology).
I started by arguing that you cannot do science that is solely directed at explaining a unique event, such as the Great Divergence. At the same time, I was unwilling to roundly denounce all literature on this topic as unscientific. There has been a number of books that I found very illuminating (to give three examples, The Great Divergence by Ken Pomeranz, Why Europe? by Jack Goldstone, and Why the West Rules – For Now by Ian Morris; there are more). But thinking and responding to comments made on the previous blog made me realize that you can do it. So here’s what I think now.
All historical events are unique, but a valid explanation of any particular event must involve a mixture of unique and generic features. Let’s use as an example the Cretaceous–Paleogene extinction event that killed off most of the dinosaurs. Currently the best explanation of this mass extinction is the Alvarez impact theory (Schulte et al. 2010). The explanation is based on a unique event: a huge asteroid hitting the Earth ~65.5 million years ago. How have natural scientists built their case?
They start with unique features – the asteroid impact itself, how big it was and where it hit. Also, that there was an Earth and it had a certain kind of biota – it is easily forgotten that all such factors must be included in the account. The next step, however, is to start building models that link the impact to extinction. The unique features provide ‘boundary and initial conditions’ (using the modeling jargon) while general theories allow investigators to build dynamic models for postulated processes. For example, a big issue is what were the environmental consequences of the asteroid impact, and climate simulations suggest that the impact was followed by a long period of global darkness and cooling.
Finally, the models generate predictions that were then tested against the data in the fossil record. The conclusions of Schulte et al. (2010) have not be universally accepted by all scientists (see the scientific correspondence associated with their article). However, nobody can deny that the huge scientific progress took place since the Alvarez hypothesis was proposed in 1980. This is a fine example of what Randall Collins calls rapid-discovery science (although he is rather pessimistic about whether social sciences are capable of it) and it deals with a unique historical event.
Nothing prevents us from applying the same approach in historical social science. For example, the Great Divergence, or the beginning of the Industrial Revolution in Great Britain. Again, the unique features of Great Britain (geography, demography, social structure, etc.) provide the initial and boundary conditions for dynamic models. For example, the realtive proximity to Americas provided an opportunity to loot the societies there. Alternatively, North America provided millions of arable acres that helped England to get out of the Malthusian trap.
Next, it is important to realize that the Industrial Revolution was a complex event that involved rapid changes in many distinct spheres, although these were connected by feedback loops. Thus, we need to have separate models addressing such questions as: How was agricultural productivity improved? Why did England escape the Malthusian trap? What were the causes of institutional change, leading to government becoming more responsive to populace? Why did the pace of scientific and technological change accelerate? And many others. Each of these questions can be modeled, with models used to make predictions to be tested against the historical record (in the same way as the climate models and the fossil record were used to test the Alvarez hypothesis).
There is one big difference between explaining the Cretaceous–Paleogene extinction event and explaining the Great Divergence. Climate models have really got quite good during the last few decades, and while we don’t have complete understanding of how and why climate changes, we do have reasonable models with which to simulate the environmental effects of an asteroid impact. In this respect historical social sciences lag behind historical natural sciences. In a few cases, we have reasonable models (e.g. demography), but usually this is not the case. For example, how do we model technological change?
And now for a dash of realism. Although questions as to why the Great Divergence occurred are fascinating and important, and eventually we will be able to address them, right now the state of historical social science does not yet permit us to develop a rigorous research program comparable to the one on the Alvarez hypothesis.
On the other hand, fifty years ago geologists, climatologists, and evolutionary biologists were in a similar state – they did not have the tools to do what they are doing now on dinosaur extinctions. The first order of business for us, then, is to develop general theories of social change that will give us the tools to answer questions about unique events such as the Great Divergence, the Industrial Revolution, why the Roman Empire fell, and many others. Building and empirically testing such general theories about history seems to me to be a much more productive way of utilizing our collective energies and talents (instead of arguing fruitlessly, as is the general tendency now).
And that is, of course, what Cliodynamics is all about.