This is not arguing for or against mono(dyo) theletism. It is simply pointing out a difficulty for anyone who adheres to older substance-based ontologies. The chief gains of the dyothelites was to argue that will is a faculty of nature, not person. This is in line with the standard fare of mind falling within the orbit of nature, not person. All that is well and good, but that is not how we talk today. Person (and mind) is associated with self-consciousness–at least in today’s discourse. This would seem to suggest that “will” should be placed within the orbit of “person” not “nature.” Of course, I am not necessarily arguing that position.
Perhaps more problematically, and as Colin Gunton argued in Act and Being, nature is an object. If will is part of nature, then “will” is an object. Yet, isn’t will something that a subject does?