well, go ahead. I doubt it will help (I have read Ott)
Christ ASSUMED a rational soul at some discrete point in time. The act of Creation was an act of Divine will. God could have chosen to not create Creation. If God had chosen to not create Creation then Christ could have never ASSUMED a rational soul (because no such thing would exist). This introduces potentiality into the nature of God (“potentiality” means it might be one thing or another, but God has no potentiality - he “is” the great “I Am,” pure absolute existence with no possibility of uncertainty). If we follow Ott’s logic to its ultimate conclusion, we are forced to accept the idea that humanity is a “necessary existence” (because Christ could not exist without it). But that is philosophically impossible - only God can possibly be a necessary existence, and a necessary existence cannot be dependent upon a possible existence (such as us humans).
And besides, the eternal Christ has infinity “existed” in a state where he did not possess a “rational soul” (ie, “before” Creation).
“united hypostatically” means united in nature. It seems to me that an infinite and eternal and unchanging God cannot be “united hypostatically” with anything that is finite and created without changing the nature of God (which is impossible).
I wish I could chat with Ott about this. He may be able to explain his thesis in a manner that I can understand. Alas, I can only hope he will explain it to me in heaven. Or, maybe somebody here could do it for him.
I’m not sure how to answer your post but with your patience I will try.
I think you are saying that if God is man, and God is absolute existence, then God as man must exist with no possibility of not existing as man. Since he is God-man then he has to exist as man as well as God, for God would not be all of God if God-man did not exist.
So it is no longer an option for the God-man not to exist. Yet this seems to force God to become man with no possiblity of doing otherwise.
So the real problem is God no longer has a choice in the matter of becoming man.
But Jesus added nothing to God because God was all that he ever was, and is, and will be without ever changing, diminishing, or growing. God is forever the same.
Now it might seem that Jesus in his human nature added something to God. Where did Jesus’ human nature come from? God. God is the author of his own human nature, whereby he gained nothing, but simply was now a man. This human nature is by the power of God, its origin.
So if Jesus didn’t exist, God lost nothing, for he is the source of everything and everything is already contained in him.
Now from Jesus’ point of view, being the Son of the Eternal Father, as man, he gives the same glory to the Father as he always gave as the 2nd person. The 2nd Person is the same person from all eternity as the man Jesus. Nothing new or added is given to the Father by the Man-Son that was not already there before time began…glory, love, thanksgiving… This is the way it was, is, and always will be in the Divine Trinity.
So the answer is that the 2nd Person did not have to become man.
Just some thoughts.