If the [Incarnation] happened, it was the central event in the history of the Earth葉he very thing that the whole story has been about. Since it happened only once, it is by Hume’s standards infinitely improbable. But then, the whole history of the Earth has also happened only once: is it therefore incredible? Hence the difficulty, which weighs upon Christian and atheist alike, of estimating the probability of the Incarnation. It is like asking whether the existence of nature herself is intrinsically probable. That is why it is easier to argue, on historical grounds, that the Incarnation actually occurred than to show, on philosophical grounds, the probability of its occurrence.

… C. S. Lewis (1898-1963), Miracles [1947]