Thanks again for your thoughts on this topic. I think at this point it would be helpful to illustrate this doctrine with something a bit more concrete. It seems I am beginning to get across what it is that we believe, perhaps now I can make clear why it is that we must believe it.
Catholicism is doctrinally built from a Christological base. When I say that, I mean that everything in Catholic theology comes out of our understanding of Who Jesus Christ Is. Our doctrines stem from this theological core like bricks stacked on a foundation.
Now I must pose a question to you:
Does Jesus Christ possess a human nature? If so, how do you understand this nature to affect the person of Jesus Christ?