Islamic economic life ran on a pervasive religious ethic rather than enforceable rules alone

Evidence

In the practical sphere, economic life, however messy, was regulated not only by technical sharʿi rules but also by a pervasive sharʿi ethic. Violations and occasional evasions of the system no doubt existed, but these never amounted to anything regular that could be installed as norms. They were relatively irregular and sporadic, having failed to constitute even a peripheral domain. The economic domain was sharʿi-minded because society, the subject, object, and predicate of Shariʿa, was sharʿi. — Wael Hallaq, Restating Orientalism, 153

Categorization

• XREF: Parallels Milgrom law-merchant material and extralegal diamond-trade ethics: norms governing economic life without centralized enforcement, here culturally rather than institutionally produced.
• ADDENDUM: Speaks to the infrastructure piece’s interest in how ethical/cultural systems function as unspoken infrastructure — here for whole economies rather than trees.