In the fifth and last subsection of this sixth chapter of Being as Communion, Zizioulas turns his attention to whether we can speak of the validity of ministry and the implications that this has for the relations between Christian communities, and especially for the relations between those who have an episcopate and those who do not. He points out that “validity” is a juridical term that suggests that ministry can be isolated from the rest of ecclesiology and that it appeals to “objective criteria” such as “faith” or “historical apostolic succession” that originally formed part of an organic community, and that

Their meaning, therefore, depends constantly on their natural context, which is the community. We have seen, for example, how this is the case with apostolic succession. The same must be remembered with regard to “faith”:  the “symbols” or “confessions” of faith were not in the early Church autonomous statements, as they are today in dogmatic manuals, but integral parts of the life and especially the worship of the community; they started as baptismal creeds and were adopted and used again as confessions for baptismal and eucharistic use. The great methodological error in the classical theories of “validity” therefore is that they tend to go to the unity of the community via these criteria, as if the latter could be conceived before and regardless of the community itself. (243)

Instead of seeing a ministry as validated by isolated and objectified “norms” we should rather see the community as validating this ministry. While this will eventually lead to “criteria,” these should be seen as arising out of the community. This means that the question becomes one of the recognition of communities and “the way in which a community relates itself to God, to the world and to other communities.” (244) While the forms of ministry may vary, the structure of the community implies something permament.

Just as the baptismal structure of the community is not basically changed by this conditioning, so in the same way the eucharistic structure must be understood as implying something permanent, its permanence being dictated precisely by its existential and eschatological nature. Similarly, it is not possible to avoid structures that express in a relational existential and eschatological way the identity of each community with those of the past, especially with the original apostolic communities, and with those of the present, implying a constant openness to the future. To take an example, the real issue between the episcopally and the non-episcopally structured communities of today would become in this approach whether or not episcopacy is essential to the Church’s proper relation with God and the world, i.e. whether or not a community with episcopacy can feel and existential identity with a community which has no episcopacy. It is in this sense that recognizing a ministry is a matter of recognizing a community. (245)

Seen in this context, the recognition of orders cannot be seen as a matter of “economy” as is often done by Orthodox theologians, for “‘validity’ is not something to be graciously, as it were, granted by one who ‘has’ to one who ‘has not.'” (245) The Church cannot recognise a sacramental reality that does not exists, for the validity of ministry involves an existential rather than a juridical matter and is concerned with the fundamental relational nature of the Church rather than simply an arrangement.