There are innumerable possible causes - institutional quality, geography, property rights, colonialism, resources, customary traditions, socio-economics, labor shortages following the Black Death, technology, a culture of freedom, marriage customs, etc. There are dozens of explanations and most of them likely have some contribution. What is most notable, to me, is the level of determinism in most such discussions. "X caused the Great Divergence." In my view, no single factor caused the Great Divergence. Many factors were required, in the right portions, in the right sequence and at the right time. Teasing out the relative contributions and the degree of necessity for each factor is interesting but the binary determinist mindset is limiting.
From Mills, cranes, and the great divergence: the use of immovable capital goods in western Europe and the Middle East, ninth to sixteenth centuries by Bas Van Bavel, Eltjo Buringh, and Jessica Dijkman. From the abstract, their suggested root cause for the Great Divergence is is private property rights.
This article contributes to the ongoing debate on the causes of the great divergence by comparing the use of expensive labour-saving capital goods—water-mills, windmills, and cranes—in medieval western Europe and the Middle East. Using novel ways of measuring, we find that whereas the use of these goods increased in Europe, in the Middle East their prevalence decreased, or they were not used at all. We investigate several possible explanations and reject most of them, including religion, geography, technological knowledge, and disparities in wages and cost of capital. Our analysis shows that differences in lordship systems and the security of property rights best explain the patterns found.I agree that property rights are an important factor and probably a necessary factor. Hernando de Soto's work on the importance of property rights for development is pretty compelling but it seems to me that the recent thirty year flowering of the Chinese economy occurred in the absence of reliable property rights so the case remains open. It is unclear to me, as important as they can be as a contributor to economic growth, whether property rights are a necessary condition.