A sabab provides a route toward a ruling. An ʿillah is the operative legal ground to which its establishment is attributed. A shart is a necessary circumstance for its realization, while a sign may simply indicate its existence.
When sabab and ʿillah are both present, attribution normally goes to the ʿillah. Where the true operative state is inaccessible or variable, a recognizable proxy may be used within a defined legal field. Qualifying sleep, valid seclusion and travel illustrate this distinct mechanism.
Finally, figuratively calling an oath or condition a “cause” does not turn it into an operative cause in every ruling. Classification must follow the particular legal effect and its prerequisites. The next section addresses further divisions of legal rulings.