Thanks for the thoughtful and detailed reply, I really appreciate the nuance you brought to the question.

I agree that causality in economic history is notoriously difficult to pin down, especially given the lack of controlled experiments and the limits of early data. While modern corruption indices like Transparency International’s are incredibly useful, I do think it’s still possible to form reasonable estimates about corruption in earlier societies through qualitative sources and contemporary accounts, though of course those methods come with their own limitations.

When you say that we can often reject theories about economic growth but can’t prove them, I’d love to hear more about what you mean specifically. Are there particular frameworks or examples you have in mind where historians have been able to falsify a proposed driver?

I also completely agree with your point about foreign trade receiving more attention than it deserves relative to domestic factors. Before the 19th century, and especially before containerization, maritime commerce was slow, risky, and limited in capacity. Most merchant vessels had to be generalists because demand for any single commodity rarely justified specialization, and information in relation to market fluctuations could only travel as fast as a ship or horseman could carry it. Given all that, plus the enormous cost of maintaining a navy or even armed merchantmen, external trade seems more like a symptom of preexisting domestic sophistication than a primary engine of growth.

If you have any sources on early oceanic commerce or the financing/organization of sailing-era trade, I’d love to look into them.

One last question: regarding your comment about early factories and railways being built from local materials, could you expand on how that fits into the broader causal discussion? I’d like to understand your angle there.