As for one who, like al-Asharī, says that capacity has no effect: if he understands necessity as customary necessity, this is not impossible; but if he construes(1) it as rational necessity, it is impossible.
As for the term “compulsion,” the dispute over it is verbal, as noted above. In linguistic usage, it does not plainly convey this meaning, which is why the Salaf rejected using it without qualification.
If the Qadariyya say:
“This is incompatible with his being a free agent, for being a free agent means nothing more than being capable of acting and refraining: if he wills, he does one, and if he wills, he does the other.”
They are told:
“That is granted. However, it may be asked: Is he capable of acting and refraining alternatively, or simultaneously? The latter is false, for while acting he cannot also be refraining, and while refraining he cannot also be acting. Acting and refraining are opposites whose conjunction is impossible, and capacity does not extend to the impossible.
“It is thus known that when we say he is capable of acting and refraining, we mean that he is capable of acting when he is not refraining and capable of refraining when he is not acting.
“Likewise, the statement, ‘The capable person(2), if he wills, acts, and if he wills, refrains,’ refers to alternatives. He cannot will both acting and refraining at once. Rather, when he wills to act, he does not desire to refrain, (3 and when he wills to refrain, he does not desire to act (3) 3).
“If this is so, then the capable person who(4), if he wills, acts and, if he wills, refrains—when he