"... and there is the beginning of a theme that will be of some significance for later Christological developments, the idea that each 'nature' becomes through their union in Christ, capable of being described in terms of the attributes of the other. But this needs the further qualifications that (i) it is the dingle divine subject, [[the Word]], who brings about this exchange of predicates, and (ii) while the humanity is substantially changed by the exchange, the divinity is not." pg 65 "Cyril has insisted that the union of divinity and humanity in Christ was *kath'hupostasin* -- something at the level of substantive reality rather than a mere appearance. This turn of phrase may have originally meant no more than an insistence that the union was not a merely theoretical matter: *kata monen ten theorian* gradually became a positive formula to denote 'what there is one of' in the union that takes place in the [[Incarnation]]." pp 67-68