[dmreedy]

The big idea is that the first lesson of history, to the point of self-parody, is that, for a given it, it started earlier and it was more complicated.

The obvious, traditional vectors of change throughout history suffer the exact same recursive "but what caused that" loop as any other broad question about the nature of things. God made creation, but who made God? You can either choose an arbitrary place to stop (God is the prime mover) or you can keep recursing, trying to put the first order threads ("A war was waged") into their contexts ("Why wage a war? Wars are expensive and risky. What drove these forces into play?)

When you start to look at the motivating factors that drive the first-order events of textbook history, the scope inevitably becomes larger and fuzzier, as you're dealing with many more variables across many more moments of decision.

It can definitely start to feel very speculative, and it is speculative. But it also provides the framework for more testable hypotheses to be explored. At the very least, it should give pause to anyone who thinks anything is obvious.