An Episcopal Dictionary of the Church

Esse, Bene Esse, Plene Esse

Terms for characterizing the significance of a doctrine or practice for the church. Esse indicates that which is of the essence of the very existence of the life of the church. Bene esse indicates that which is of benefit for the life of the church. Plene esse indicates that which is of the fullness of the Church's life. These terms have been frequently used with respect to the role of the historic episcopate in the life of the church. This question has often been raised in the context of ecumenical discussions, especially with churches that do not have an episcopal ministry and do not require episcopal ordination of clergy. The statement "No bishop, no Church" would reflect the position that the historic episcopate is of the esse of the church. This view, strictly applied, serves to "unchurch" Protestant denominations that do not have the episcopate. It also serves to restrict severely the possibilities for Anglican ecumenical relations with these churches. 

The historic episcopate (as locally adapted) was identified by the Quadrilateral adopted by the House of Bishops in 1886 as one of the four parts of the sacred deposit of the faith that are "essential to the restoration of unity among the divided branches of Christendom." The historic episcopate was likewise identified by the Lambeth Conference of 1888 as one of the four bases for Home Reunion. See the Chicago-Lambeth Quadrilateral 1886, 1888 (BCP, pp. 876-878). The other three "essential" parts identified by the House of Bishops in 1886 were the Holy Scriptures of the OT and NT as the revealed Word of God; the Nicene Creed as the sufficient statement of Christian faith; and the two sacraments of Baptism and the Supper of the Lord, ministered with unfailing use of Christ's words of institution and of the elements ordained by Christ. The other three elements of the Lambeth Conference Resolution of 1888 are similar to the Chicago declaration, except that the Apostles' Creed as the Baptismal Symbol is mentioned along with the Nicene Creed as the sufficient statement of Christian faith. 
The distinction of esse and bene esse with respect to the episcopate can be traced to the thought of Richard Hooker (c. 1554-1600). He believed that the apostles left bishops with authority above other pastors and that the church has power to determine its own positive law and governance. But Hooker also believed that episcopacy does not belong to "the essence of Christianity." On the other hand, nineteenth-century Tractarians took the position that Christ created the apostolic order. For example, in Tract 4, John Keble (1792-1866) doubted that there was assurance and safety for salvation except in the sacraments of the apostolic Church of England. Keble and other Tractarians believed that episcopacy was of the esse of the church.
The term plene esse was used in essays by H. W. Montefiore and Kenneth M. Carey in The Historic Episcopate (1954), edited by Carey. This collection of essays was published in response to the controversy concerning whether the Church of England should enter into full communion with the Church of South India. In the Church of South India, episcopal and non-episcopal churches came together on an episcopal basis. Clergy who had not been episcopally ordained were not reordained by bishops. But all future ordinands were to be episcopally ordained, so that the Church of South India would eventually be an episcopal church whose clergy were all episcopally ordained. Carey admits that the interim presence of nonepiscopally ordained clergy was an admitted "anomaly" for an episcopal church. Nevertheless, the essays by Montefiore and Carey support full communion with the Church of South India because the episcopate is of the plene esse, or fullness, of the church-not the essence. In 1955 the Convocations of Canterbury and York approved limited inter-communion between the Church of England and the Church of South India. A similar plan and understanding of episcopacy was the basis of the proposed Lutheran-Episcopal Concordat (1991). See Historic Episcopate; see Chicago-Lambeth Quadrilateral. 

Glossary definitions provided courtesy of Church Publishing Incorporated, New York, NY,(All Rights reserved) from “An Episcopal Dictionary of the Church, A User Friendly Reference for Episcopalians,” Don S. Armentrout and Robert Boak Slocum, editors.