The nature wills and acts, the person chooses, accepting or rejecting that which the nature wills. (Vladimir Lossky, The Mystical Theology of the Eastern Church, 125)
In the Christology controversies of the 6th-7th centuries, monothelitism asserts that Jesus Christ has only one will, while the 5th and 6th Councils (Constantinople II and III) assert that Christ has two wills. The dyothelite position asserts that because Christ has two natures: one human, one divine, therefore he has two wills, for the will is a property of nature. The argument proceeds on through the category of energies, for energies come from the nature. Two natures imply two energies which imply two wills.
Whatever the merits of such an argument, the interesting part is this relation of "will" to "nature." If the nature is the one that wills, then does that mean the person does not will anything? Here, we see Vladimir Lossky coming up with an interesting solution to the problem. Since it is the nature that wills, a distinction is made between "will" and "choice." It is undeniable that the human person is the one that chooses one thing or the other, so Lossky asserts that the choice is made by the human person, AFTER the nature wills and acts. That way, Lossky can seemingly do justice to both Constantinople II and III, and the common sense notion of how human beings actually decide one way or the other. Such a solution would seemingly solve the problem of Pelagianism and the Eastern view of Synergism. If a distinction is made between "will" and "choice," then the human person can have no "will" not totally affected by sin, and yet he is free to choose God or reject Him.
Such a view of the doctrine of man would certainly be strange, and contrary to the Augustinian and Calvinist view of Man. Yet it seems necessitated if one wants to hold to the philosophy behind dyothelisim and also hold that the person chooses. That leads us to a problem: If we hold to the philosophy of will behind Constantinople II and III, we must either reject the view that a persons wills, and reject the Calvinist and Augustinian view of Man. Alternatively, we could hold to the philosophy of will behind Constantinople II and II, reject dyothelitism, and we can continue to be Calvinist and Augustinian in our doctrine of Man. Or, we could be dyothelites, reject the philosophy behind Constantinople II and III, and continue to be Calvinist and Augstinian. I think the third option is a more viable project to explore, and one I intend to look into in the future.
From a modern perspective, it is weird to assert that the nature wills following which the person then chooses. What does it even mean in saying that the person rejects what the will wants, since what I want is what I will to want? Is "willing" to be equated to "desire"? Such a move would make the concept plausible in the context of discipline and self-denial, yet "will" as "desire" is not how "will" is normally understood. "Desire" is normally understood in the context of the emotions, not the will. It is therefore unclear just what exactly is meant by stating as Lossky does that "the nature wills and acts," with "the person chooses, accepting or rejecting that which the nature wills." It sounds positively incoherent, but who knows?