He went on to say, “Moreover, they do not declare unbelievers those who disagree with them on these points, whereas one of the indispensable conditions of valid consensus is that anyone who rejects it must be pronounced an unbeliever, with no difference of opinion among the Muslims on that score. If what they claimed were truly consensus, their opponents would have been declared unbelievers—indeed they themselves would have been, because they often depart from those very positions.” (1)

I reply:
Scholars and devotees of the religion are not obstinate by nature, yet a person may presume that a question is settled by consensus when in fact it is not, simply because he has never encountered the opposing view; conversely, there may be a genuine consensus of which he remains unaware. Their use of consensus as proof is therefore akin to their use of textual evidence: at times a text has not reached a given scholar, and at other times he supposes a text to exist when it is in fact weak or abrogated.

Furthermore, the fault he ascribes to them also befalls him, for in certain issues he abandons positions that he himself has listed in this very book as matters of consensus.

Equally unfounded is the obligation he places on them to declare every dissenter an unbeliever, for many leading scholars do not anathematize the violator of consensus.

His statement, “Whoever opposes consensus is an unbeliever, with no disagreement among the Muslims,” likewise stems from unawareness of the contrary view, even though that contrary view is famous and recorded in numerous works. Al-Naẓẓām himself, who denied that consensus is authoritative proof, was not branded an unbeliever by Ibn Ḥazm or by others. Those who do declare the dissenter an unbeliever do so only after the well-established, manifest consensus has reached him. Many consensual rulings never reach large numbers of people, and in countless areas of debate among later scholars one party will claim consensus: either the claim is merely conjectural, not definitive; or the information has not reached the other party; or he believes that the necessary conditions for consensus have not been met.

In addition, scholars have disputed many types of consensus as to whether they constitute binding proof: tacit consensus, the consensus of the four Rightly-Guided Caliphs, the second generation’s agreement on one of two opinions found among the first generation, and a supposed consensus in which some members demurred before their generation came to an end—for the very extinction of the generation is the basis, indeed the pre-condition, of consensus—among other cases.

Their disagreement over certain categories—whether they amount to consensus that must be followed—is just like their disagreement over certain kinds