I agree that you can not start with just any presupposition and I did not mean to insinuate that I am a Christian existentialist. I don't believe faith should be a blind "leap" without reasonable basis.

I see a great deal of evidence in the natural world of the God revealed in Scripture: order in the universe, complexity of life, explanation of origin of evil, basis for reality of cause and effect, etc. Then a closer look at the New Testament reveals significant evidence that a group of men and women saw Christ alive after his death and were willing to die for their conviction that he was the son of God.

But before anyone can arrive at that belief they must presuppose that the universe is not a closed system but rather one in which a creator can reach down into and defy known logic (a miracle).