Ijma: The Consensus of the Scholars Is Binding

Ijma, the agreement of the qualified scholars of the Muslim community on a point of law, ranks as the third of the four sources of Sunni jurisprudence, following the Quran and the Sunna and preceding qiyas, analogical reasoning. Once such an agreement has genuinely formed, the doctrine holds, it becomes binding and is no longer open to challenge by a later individual scholar, however well qualified, because the collective judgment of the qualified community is treated as protected from a certain kind of error that any single scholar might fall into alone. Historically ijma has always meant a consensus already reached in the past, whether recent or remote, rather than a live, contemporaneous vote taken in the present; a ruling counts as established by ijma when later generations can point to a settled agreement among earlier scholars, not when a body convenes today and votes. This backward looking character is part of what gives ijma its binding force: it closes a question that has already, in fact, been closed by the scholarly community across time, rather than opening a new one. A further distinction separates an explicit consensus, in which every qualified scholar states the same ruling outright, from a tacit consensus, ijma sukuti, in which a position is voiced by some scholars and left unchallenged by the rest, a weaker form some jurists accept as binding and others do not.

Agreement in principle that ijma binds has never settled agreement on what actually constitutes it, and the dispute has real consequences for how much of Islamic law counts as closed. Scholars differ over whether a valid ijma requires the agreement of every qualified jurist alive in a single generation, or something looser; over whether the agreement of the Prophet's Companions carries a decisive weight that a later generation's consensus does not; and over whether a consensus once formed can ever, in principle, be reopened by a later age that judges the earlier agreement to have rested on a mistaken premise. The Jafari school, the primary legal tradition of Twelver Shia Islam, accepts a version of ijma but grounds its authority differently from the Sunni schools: consensus is binding, on the Jafari account, not because scholarly agreement is inherently protected from error, but because the Imam is held to be present, even if unrecognised, among those who agree, so that it is ultimately his authority working through the consensus that makes it binding rather than the consensus as such. The Zahiri school, represented by the jurist Ibn Hazm, narrowed the question further still, accepting as binding only the consensus reached by the Prophet's own Companions and refusing the authority of any later scholarly agreement, a stricter standard than the other schools apply.