Loftus discusses how Christianity is a leap of faith beyond the evidence on page 55.
The first point that needs to be established is something that has already been mentioned in this forum (L 3.1); that when non-theists ask for evidence, they are typically asking for scientific evidence for a metaphysical issue. Obviously, the most pertinent question is what they would consider to be proof of God’s existence. The customary answers to this question show that they either have a great sense of humor or that they should consider a career in fiction. In a debate with William Lane Craig, Ken Parsons had repeatedly told Craig that the resurrection appearances of Jesus were nothing but hallucinations. When Craig asked the all important question of what it would take for him to believe, Parsons described an Olympian-style tale of a Zeus-like figure descending from the clouds with a voice that boomed calling out Parsons’ name, etc., to which Craig responded that Parsons was merely having a hallucination! This drew uproarious laughter and applause. Many responses will be similar to Parsons in regards to what would constitute as proof of God’s existence to them. Examples are a restored limb, God’s name etched on every subatomic particle, stars arranged to form God’s name, just to list a few. However, no one is able to justify why these would serve as proof. Every possible scenario dreamed up could be the result of vastly advanced aliens, some as-yet-undiscovered law of physics, a biological oddity, etc. The point is that there is no way to establish a scientific, empirical maxim that would serve as proof of something metaphysical. Additionally, non-theists have a terribly hard time admitting that they work from a sliding scale. If those proofs were provided, it still wouldn’t be good enough. This can be demonstrably proven with examples like extra-biblical attestation of Pontius Pilate, the Hittites, Belshazzar, etc. For many decades, Christian critics used those people to claim that the Bible was not historically accurate because there was no evidence for these people outside of the Bible. Therefore, nothing in the Bible was historically reliable. When extra-biblical evidence for these people was found, the goal-shifting started. Now the criterion for truth was much stricter. Attestation of these people was too mundane. Instead of extra-biblical evidence for mere people or places, impartial confirmation of biblical miracles was needed. When the creation story in Genesis was held to be contrary to the steady state model of the universe, along comes the Big Bang confirmation which is in accord with the Bible narrative. Now, focus has narrowed down from overall cosmology to biological diversity through universal common descent. There are other examples that will show up in later posts.
To recap this point, critics of Christianity say there isn't evidence. When asked what would constitute as evidence for them to believe, they dream up ridiculous scenarios that they can't guarantee would be convincing to any more people than the number that already believe. When there does appear to be evidence for Christianity, skeptics will then manufacture newer, stricter standards to keep the information from qualifying as evidence. In the end, it's a moving target and then never intend to allow anything to satisfy it.
The second point in response to Loftus’ assertion is that there actually is evidence for Christian spirituality and that it isn't a leap of faith in the sense that he states; the evidence just happens to be in the discipline of metaphysics. There are multiple rational, logically sound, philosophical explanations for God’s existence. When Loftus parrots the obligatory leap-of-faith-without-evidence routine, he makes it seem like a rock solid criticism when in fact, it’s downy soft. Most of the time, these explanations for God's existence are dismissed because the person advocating them is just a Christian apologist. Nontheists feel that arguments from Christians should never be trusted because Christians have a bias towards their belief which occludes their rationality. This tactic by non-Christians is called the genetic fallacy. The nontheist says that explanations for God's existence should only be trusted if they are advocated by impartial, non-Christians. Obviously, the person making the explanation isn't the issue. The information is what actually should be considered regardless of the source. Even when nontheists don't commit the genetic fallacy, they fall back to the "lack of evidence" position. What they typically won't acknowledge is that there are and have been plenty of people who are hostile to Christianity who become Christian because they "followed the evidence". In the end, the issue isn't about the evidence. The issue is about why someone would cling to the belief that there isn't a God when no person can know such information. If anything, atheism is a greater leap of faith than Christianity.