Philosophical Terms Defined by the Council of Chalcedon

By Bishop Joseph Boyd (Ancient Church of the West)

We commemorate the Fourth Ecumenical Council this Sunday, remembering the Fathers of the Church and their witness of Christ's dual natures, His being as truly God and truly man. We must also remember the terms that they clarified. Up until 451AD, the terms "essence", "nature" and "person" had been used interchangeably and confusingly by many of the Fathers of the Antiochian, Roman and Alexandrian Schools. Through the work of the Council of Chalcedon, held for many months and witnessing many miracles, the philosophical terminology of the Church's Christology was hammered out and clarified for the first time. Those terms are important for all Christians to know.

They are...

1) Ousia - Ontological Ground of Being, an "Essence", an irreducible unity that is a "thingness in and of itself." God, and perhaps all of creation on the other hand, are the only things that could inhabit this category, and creation only in a derived, contrasting sense.

2) Hypostasis - Causality, literally "Under Standing", the underlying mediating action of reality rooted in the existence of a thing, the reality upholding what is visible to the observer.

3) Physis - Nature, the observable character, attributes, the outer existential qualities that are the outer manifestation of the Hypostasis that others can interact with and know.

4) Prosopon - "Person", "Mask", "Face", the combined totality of appearance and experience in which Ousia, Hypostasis and Physis are perceived by others. Prosopon also implies "Thelema" through our experience with other humans and animals, free will, agency, choice, decision, moral responsibility and personhood as perceived and given from the recognition of others. Physis works it's way out amongst other natures, building narratives and achieving moral ends as the Prosopon.