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.