One True Church?

(add ... history of ecumenical movement? visions/strategies of ecumenism?

I. What Is the Unity of the Church?
1. The unity of Father or Son or Holy Spirit (1 Cor 12:12-13, Gal 3:28).
Abuse: Unitarian homogeneity/totalitarianism.
2. The unity of Father and Son and Holy Spirit (John 17:20-23).
Abuse: Tritheistic pluralism/anarchy.
Either way, the Church's unity is God's unity, a gift and reflection of God.
II. What Is Unity's Basis or Medium?
Catholics and Orthodox: Communion with the apostles' successors
(Catholics: and ultimately the Bishop of Rome).
Effect: Unity is formal, institutional continuity.
Protestants: Obedience to Scripture through the gift of apostolic faith.
Effect: Unity is "invisible," doctrinal agreement.
Effect: Confessions and statements of faith proliferate.
Pentecostals and charismatics: The presence of God through the Holy Spirit.
Effect: Spiritual gifts and fruit are the only final evidence.
Effect: Unity is spiritual, ethical, 'felt'.
III. All of the Above?
Lesslie Newbigin: These types are each insufficient.
Christ always has two mediators: Holy Spirit and Church
("The Church's One Foundation").
Bishops, Word, sacraments are media of the Holy Spirit, and ...
the Holy Spirit's action takes concrete verbal, sacramental, and institutional forms.
Disunity compromises the Church's witness, injures the body of Christ.