Ījāb al-ṣāniʿ in this context refers to a metaphysical account in which effects follow from their source with necessity. In contrast, the discussion of a volitional agent (fāʿil mukhtār) stresses the relation of power and will to action.
If an agent’s action is portrayed as the unavoidable output of a natural process with no room for will or choice, the assertion is more than the neutral use of the word “cause”: it becomes a substantive theological theory.
Example: Cloth warming near fire is a physical relation. It does not by itself prove a particular metaphysical theory about divine volition and creation. The limits of analogies between Creator and creature must be observed.