The simple answer stumpy is that we have accepted the other tenets of Christianity for various reasons and have come to the conclusion that if we accept Christianity we must accept all of it.
You ask for empirical evidence, though I believe that there is certainly some I would offer that I believe in Christianity in part because I believe that empiricism is not the only way to obtain knowledge so it would probably be fruitless for me to try and convince you, nonetheless I will throw out some reasons people might come to a belief in Christianity.
1.) Personal experience with the depravity of mankind both inside ourselves and in our interactions with others causing us to realize our need for a Savior.
2.) Historical evidence for the honest to goodness, actually happened resurrection of Jesus Christ (see Josh McDowell or Lee Stroebel books for a detailed explanation if you so desire).
Edited by Adminnemooseus, : Added a couple of blank lines.
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