[Nestorius] insisted on two
natures not, as he was accused of doing, in order to express two separate
realities (‘two sons’). The one individual reality of Jesus Christ, however,
could not be defined as nature or hypostasis but instead had to be understood
as one prosopon. In the texts written before the council Nestorius thus
conceived of the joint prosopon—joint, that is, of Godhead and
humanity—as the ‘person’ of Christ. The word does not straightforwardly denote
‘person’ in a modern sense (nor does any of the alternatives offered at the
time). While it is often designated the ‘individual’, it did not usually evoke
notions of personality and substantial integrity. That said, prosopon was,
to Nestorious, the concrete reality of a person as it could be perceived by,
and present itself to, another it was an ‘I’ in relation to a ‘you’, and in
this way surely more than just an outward presentation. The properties
essential to a ‘person’ were disclosed to the ‘other’ through, or at the level
of, its prosopon (or, in the reverse perspective: allowed the ‘other’
perception and cognisance of them), as had been the case of Theodore of
Mopsuestia. In this way, the word seemingly failed to express without ambiguity
the substantial reality and personality of a human subject. After all, the term
prosopon could still be used, as it had been in the world of the
theatre, to designate an adopted rule. It also carried overtones from its use
in biblical exegesis. Since Origen, interpreters had sought to establish which
‘person’ or ‘character’ ‘spoke’ for instance, the verses of the Psalms
(exegesis ek propsopou). The Psalmist might speak from the propsopon of
the divine Wisdom at one point, and from that of a pious man praying at
another; or the prophet could speak directly from the prosopon of God.
Such usage was at a distance from the use of prosopon (‘person’) in an
ontological sense. And so Cyril criticized the idea for its seemingly exclusive
external focus. When he criticized the conjunction of the divine and human
natures ‘merely’ in a prosopon, he latched on to these connotations that
could seem to reduce the ‘person’ to no more than an appearance, something
where unity remained at an outside, surface level, not forming a real
individual subject. Yet the use of propsopon as synonymous to hypostasis
to denote one of the there divine ‘persons’ in the Trinity shows that this
understanding of the term was narrow and tendentious. (Richard Price, The
Council of Ephesus 431: Documents and Proceedings [Translated Texts for
Historians 72; Liverpool: Liverpool University Press, 2020, 2022], 79-80)
In a footnote to the above, we read:
It seems doubtful, however, that
he also thought of the joining of two prosopa of the divine and the
human natures, respectively, in the incarnation (which might have lent itself
further to the criticism of ‘two sons’)—and which the theory of a joint prosopon
logically seems to require. This understanding is certainly expressed in
Theodore of Mopsuestia and also follows logically from Nestorius’ later
reflections in the Liber Heraclidis. In the Liber Heraclidis (after
Ephesus)—but only then—Nestorius appears to have developed the understanding of
Christ’s prosopon and its relationship to the two ‘natures’ and hypostaseis
into a more systematic presentation of a ’prosopic union’—resembling,
structurally at least. Cyril’s hypostatic union. We must note, however, that in
the surviving texts from the period up to Ephesus the accusation of teaching
two prosopa is never levelled against him. The language is also
completely absent from the excerpts of Nestorian texts selected and presented
for the purpose of his conviction as a heretic. Had he used the phrase, such an
omission from the criticisms and denunciations of the time would be difficult
to explain. (Richard Price, The Council of Ephesus 431: Documents and
Proceedings [Translated Texts for Historians 72; Liverpool: Liverpool
University Press, 2020, 2022], 79 n. 129)
