I'd like to comment in more detail on the neo-Apollinarian Christology of J. P. Moreland and W. L. Craig, which they present in Philosophical Foundations for a Christian Worldview (IVP, 2003).
A few preliminary comments:
i) When I classify a position as "heretical," I'm not using ancient church councils as my standard of comparison. I'm Protestant.
I don't object in principle to church bodies declaring certain propositions to be heretical. Indeed, that's a duty of the church. However, it's not an official declaration that makes it heretical. Rather, it's because certain propositions are heretical that a corporate declaration is merited.
A basic problem with making the heretical classification contingent on an "official" declaration is that, by that logic, Arianism wouldn't be heretical unless, say, an ancient church council condemned it as heretical.
ii) Regarding orthodox Christology, the basic duty of Christians is to affirm the constituent elements of Christology presented in the NT, and avoid beliefs or formulations that explicitly or implicitly deny one or more constituent elements. Basically, to affirm the full humanity and the full divinity of Jesus.
If they have a muddled view of how those interrelate, that's understandable.
iii) Some Christians have a higher responsibility to avoid basic doctrinal error (Cf. Lk 12:36; Heb 13:17). I'm not suggesting that Craig and Moreland are hellbound. But their position is a pretty straightforward denial of the Incarnation, despite their efforts to finesse it.
iv) To briefly state my own position, I think the Incarnation has an ineluctable element of mystery. That's in part because God is somewhat mysterious. God's mind is infinite, our minds are finite. God's mode of subsistence is categorically different from ours.
This doesn't mean we can have no true understanding of God, but God surpasses complete understanding.
By the same token, a divine incarnation is unparalleled in human experience. That's not something we can grasp from the inside out. So there's an element of mystery to that as well.
However, we have some understanding of the constituent elements. We have some understanding of the divine nature. Divine attributes. That's knowledge by description. And we understand human nature firsthand. That's knowledge by acquaintance.
Moreover, we can also use analogies to gain some understanding of the hypostatic union.
v) To be truly divine, Jesus must have all the divine attributes. To be truly human, Jesus must have a human body as well as human psychology. Of course, his mindset isn't confined to human psychology. It's more complex. His mindset includes divine psychology.
vi) I don't view the hypostatic union as a pipeline that pipes divine properties into the human nature or human properties into the divine nature. The Incarnation doesn't humanize God or divinize human nature. These remain what they are, in their distinct integrity. There's no intermingling of divine and human properties. They don't leak into each other and blend into each other, like mixing red and yellow to produce orange. The Incarnation doesn't change God.
There's an asymmetry in the relation. In the hypostatic union, the divine nature affects the human nature, but the human nature does not affect the divine nature. The divine nature remains in control.
Craig and Moreland say:
In the Incarnation–at least during his state of humiliation–the Logos allowed only those facets of his person to be part of Christ's waking consciousness which were compatible with typical human experience, while the bulk of his knowledge and other cognitive perfections like an iceberg beneath the water's surface, lay submerged in his subconsciousness (ibid. 611).
A basic problem with that model is that many times in the Gospels, Jesus exhibits a distinctly divine awareness. Indeed, that's one line of evidence for the deity of Christ.
…the Logos contained perfect human personhood archetypically in his own nature. The result was that in assuming a hominid body the Logos brought to Christ's animal nature just those properties that would serve to make it a complete human nature…Such an interpretation of the Incarnation draws strong support from the doctrine of man created in the image of God…in being persons, [humans] uniquely reflect God's nature. God himself is personal, and inasmuch as we are persons we resemble him. Thus God already possesses the properties sufficient for human personhood even prior to the Incarnation, lacking only corporality. The Logos already possessed in his reincarnate state all the properties necessary for being a human self (ibid. 608-09).
Several basic problems with their argument:
i) There's the use of Aristotelian and evolutionary categories (animal nature, hominid body). That's not something they can validly prooftexts from the Biblical imago Dei.
ii) But more deeply problematic is how they define the imago Dei. They just assume that the imago Dei stands for the psychological properties that make humans human. But Craig and Moreland don't even attempt to offer any exegetical justification for that crucial assumption. And this is in the tradition of Christian philosophers and theologians who use the imago Dei as a cipher for whatever they deem distinguishes humans from animals, such as reason. But that's not an exegetical conclusion.
Likewise, to say God is personal and we are personal, therefore the imago Dei mirros divine personhood is not a valid inference from what Scripture says about the imago Dei. Rather, they begin by stipulating some communicable attributes, then ascribe that to the imago Dei. But they haven't begun to demonstrate that that's the concept of the imago Dei in the context of Scripture.
iii) The closest thing to that is Eph 4:24 & Col 3:10. But it isn't clear that Eph 4:24 denotes moral properties rather than moral ascriptions (i.e. imputed righteousness). And even if Eph 4:24 refers to actual virtues, those aren't innate moral properties, but acquired moral properties, via sanctification.
Regarding Col 3:10, although knowledge is an intellectual property, that's hardly exhaustive of human psychology. What about emotions?
Moreover, Col 3:10 isn't referring to innate psychological properties, but acquired knowledge via the historical revelation of the Gospel (cf. 2:2). That's not given in the imago Dei. Rather, that's historical knowledge.
iv) There's more to human psychology than possession of certain psychological properties. There's vulnerability to psychological harm. How we experience those properties in a real-world setting. Take fear. Or pain. Or depression.
Or something as simple as taste. When Jesus eats fish, does the divine nature taste fish? No. The brain or soul tastes fish. The embodied soul tastes fish.
The divine nature can't experience human sensation via human sensation. That would change and humanize God. Even if God knows what pain feels like, that's not in virtue of the hypostatic union. God has a divine mode of knowledge.
Even if (ex hypothesi) the divine nature of Christ had human psychological properties, that's hardly enough to confer a human viewpoint or mindset. If the divine nature of Christ can't be affected by his surroundings, if hurting the body doesn't hurt his divine mind, then he doesn't have a comparable psychological experience. It isn't just a question of having certain psychological properties, but what one is able to experience through those properties. Take televised warfare. You can see the carnage, but you can't be harmed by what you see. It poses no threat to you. You don't feel the gunshot wound.
v) Another problem is how Craig and Moreland are able to partition the psychology of Jesus from the Father and the Spirit if his "soul" just is the Son. If it's his divine nature that experiences human emotion, the divine nature is common property of the three persons. So how is that compartmentalized? How do Craig and Moreland avoid patripassianism?. They can't just invoke mystery willy nilly. There are certain conditions that warrant mystery. If they withdraw a necessary condition, then they're stuck with the straightforward implications of their position.