I've mentioned this before, but I might as well do it again: we don't know anything about historical causation.
The crime rate has fallen again. And despite sophisticated statistical models, camera-equipped cell phones everywhere, less mendacious police stats, and a general application of a huge amount of skilled brain power, nobody knows why. This is happening right now, right here, all around us as we go through our day.
How are we supposed to explain why the Roman Republic fell? What the economic effects of the Black Death were? Why one group of people prospered while another languished? How the Industrial Revolution started? The amount of information available about those things is miniscule compared to the crimes stats of one medium-sized town in Pennsylvania.
It's not that I'm saying it's not worth trying to answer these questions. It certainly is. It's just that I can't believe anyone would say "this is the explanation".
But, of course, the incentives of academia are not the incentives of the rest of the world, and these incentives don't encourage ambiguity or degrees of confidence, and certainly not conclusions that violate predefined norms of ethnicity, sex, or religion. And most historical work is now done in the Academy. What do we miss because the pursuit of tenure is not the same as the pursuit of truth?
I'd like to think we'll figure some things out. But some will be forever unknown. And others will have only a relatively small degree of confidence. We'll just have to live with that.