Medieval Islamic scholarship had a quality-control mechanism called *isnad* — every claim in a hadith had to be traced through a named chain of human transmitters, each one accountable for what they passed on. The idea was that knowledge degrades silently when no one owns its transmission. Product teams face the exact same problem, and almost never solve it. Al-Ghazali, writing in *The Incoherence of the Incoherence*, argued that borrowed conclusions without traced reasoning are epistemically hollow — you have the answer but not the conditions under which it's true. In product work, this surfaces when a decision from eighteen months ago gets inherited by a new team as settled fact: 'We don't support that use case.' Why? 'We never have.' The original reasoning — a resource constraint, a founder instinct, a specific competitive moment — has been dropped from the chain. What travels forward is the conclusion alone, stripped of the conditions that made it valid. The discipline Al-Ghazali would recognize is requiring every inherited constraint to carry its reasoning with it. Not as documentation busywork, but because a constraint whose origin you cannot reconstruct is not a constraint — it's just institutional sediment.

Pick the oldest 'we don't do that' in your current product and trace it back — whose decision was it, and does the reasoning still hold in conditions that have since changed?

Drawing from Islamic philosophy (Al-Ghazali / hadith epistemology) — Al-Ghazali (The Incoherence of the Incoherence, c. 1095 CE)