What is Apollinarianism, and what’s really wrong with it?
Apollinarianism is a well-known Christological heresy; a way of understanding the person of Christ that historic Christianity rejected. The orthodox Christian way of thinking about the person of Christ is summed up in the chalcedonian definition. In brief, it is that Christ is one person who is fully human and fully God. He has everything necessary for a complete human nature, and he additionally has everything necessary for a divine nature. Is Jesus a person? Yes. Is that person divine? Yes, because a person with a divine nature is a divine person. Is that person human? Yes, because a person with a human nature is a human person. But we are still only talking about one person, something possible because Christ has two natures, not just one.
