C.39:2 - Problem
A desired result and a plausible label leave a gap. A found source can describe something successful without showing how to reproduce the relevant contribution under different conditions. Conversely, a useful description may be rejected because its vocabulary differs from the receiving practice.
The practitioner needs to construct and examine the obtaining explanation. Listing sources or drawing arrows does not do that work. A usable connection may need an input conversion, a choice, a shared condition or a return after failure; repeating each available operation can leave exactly that connection unexplained. Detailing every action is also wasteful when one unknown join decides feasibility and the other operations are already qualified.