[The Sixth Argument]
It may be argued:
If revelation and reason conflict, revelation must be given precedence, because reason attests to the truth of everything revelation reports, whereas revelation does not attest to the truth of everything reason asserts. Nor does knowing that revelation is true depend on everything reason asserts.
[The Role of Reason]
Clearly, this argument, if advanced, is more cogent than theirs. As some have said:
“Reason need only make known to you the Messenger’s truthfulness and the meanings of his words.”
Others have said:
“Reason is a governor: it appointed the Messenger, then dismissed itself.” For reason establishes that the Messenger, may Allah bless him and grant him peace, must be believed in what he reports and obeyed in what he commands.
Reason establishes the Messenger’s truthfulness in a general and unqualified manner.
This is like a layman who knows who the mufti is, directs someone else to him, and explains that he is a scholar qualified to issue legal opinions. If the layman who directed him and the mufti subsequently disagree, the person seeking a legal opinion must give precedence to the mufti’s statement.
If the layman says to him:
“I am the basis of your knowledge that he is a mufti. If you give his statement precedence over mine when they conflict, you undermine the very basis by which you knew him to be a mufti.”
The person seeking a legal opinion replies:
“When you testified that he was a mufti and provided evidence for that, you testified that his judgment must be followed rather than yours, just as your evidence established. My agreement with you on this particular point does not entail agreement with you concerning each individual issue. Your error in disagreeing with the mufti, who is more knowledgeable than you, does not entail that you were mistaken in knowing him to be a mufti. If, through independent judgment and reasoning, you determined that he was a mufti, then disagreed with him through independent judgment and reasoning, you were mistaken in the independent judgment and reasoning by which you opposed someone whom you are obliged to