What is the central doctrine of Christianity, the incarnation or the cross? Christmas or Easter?
What is the root heresy, the corruption or denial of the central doctrine?
What is the motivation for and consequence of this error?
What is the branching tree of heretical options that grow from this single root?
What is the relationship between the Gnostic opposition of flesh and spirit, and the oppositions between human persons and human nature?
Perry Robinson of the Eastern Orthodox blog, Energetic Procession, gives a stunning and confrontational treatment of the above, and more.