An unrestricted general term has not had members removed by a recognized specifying proof; the textbook treats its indication as conclusive. A specified general term has some members excluded, and the remaining scope is treated as presumptive.
وَأَحَلَّ اللَّهُ الْبَيْعَ وَحَرَّمَ الرِّبَا
Allah has permitted trade and forbidden usury.
The general reference to trade does not override proofs excluding particular transactions. Specification is grounded in evidence, not an interpreter's preference.