and which they have reported from their predecessors—the very fact that they concur upon it, even though they do not declare, “This is taken from the Book or the Sunnah,” may, in my view, carry the same authority as a Sunnah on which consensus has been reached. Their agreement cannot be the product of mere opinion, for the moment opinion enters, disagreement appears.

182 – I said, “Describe to me what comes after that.”

183 – He answered, “Next is the knowledge kept by the specialists. No binding proof can be established by that elite knowledge unless it is transmitted through a route in which the possibility of error is eliminated.

184 – The final stage is analogy (qiyās). One matter may not be compared to another unless its point of departure, its source, and its final outcome—from beginning to end—match the original case, so that it truly shares the same purport as the precedent.

185 – It is not permissible to splinter off in any of the avenues of knowledge I have just outlined.

186 – Matters remain upon their foundational principles until the general body of Muslims unites to move them away from those principles.

187 – Consensus (ijmāʿ) is a proof regarding everything, because error cannot enter into it.”

188 – He continued. I said, “As for the first type of knowledge you mentioned—the transmission of the laity from the laity—that is exactly as you have stated.

189 – Now, the second category, about which the common people never disagree but rather concur and convey the unanimity of those before them—do you recognize it well enough to describe it? Or do you think that the laymen who transmit from laymen are like those you cited concerning the basic obligations? In that earlier instance, those transmitters were both scholars and ordinary believers, and we do not find any adult Muslim of sound mind who doubts that Allah has made four units obligatory in the noon prayer. Is the matter at hand different from this?”

190 – He replied, “Yes, it is of a different kind.”

191 – I said, “Then describe it.”