An ecclesiological theory which has been popular since the time of the Slavophile philosopher Alexis Khomiakov first defined it is that ecumenicity—the idea that a particular council is of universal, infallible significance for the Church—is determined by the reception of the whole body of the Church. That is, while a particular council may declare itself to be ecumenical, it may later be regarded by the Church as being a Robber Council, that is, a council which did not declare the truth but rather heresy. Likewise, a council may properly teach the truth but not be of universal significance for the Church. Such councils are usually termed local. That a council must be "received" by the Church before it can be considered ecumenical is sometimes termed receptionism.

Receptionism was formed primarily in opposition to Roman Catholic viewpoints on the same question. For the Roman Catholic Church, a council's ecumenicity is primarily determined by its ratification by the Pope of Rome. Orthodoxy does not have the same ecclesiological structure as Rome, however, and so Khomiakov and others attempted to formulate another model by which the infallibility of Ecumenical Councils may be determined.

A form of receptionism (or, at least, language which is conducive to receptionist thought) may also be found in the 1848 Encyclical of the Eastern Patriarchs, which proclaims against papism that the guardian of the truth is not the office of the pope, but the whole people of God. (Orthodox Wiki)