For example, I have heard of a handful of Germans today who for one reason or another say the Holocaust never happened. In light of the thousands of eye witness accounts, is it sensible to say that?
Another example, there are atheists today who for one reason or another say the Resurrection never happened, and not necessarily because they have ever looked into the historical primary and secondary sources.
In light of the hundreds of people who died at Roman hands in the 1st century, refusing to recant that they had seen the risen Lord, is it sensible to label their testimony a delusion, or inherited from their parents, without any thorough investigation at all?
As for those who had seen Christ themselves:
"I passed on to you what was most important and what had also been passed on to me. Christ died for our sins, just as the Scriptures said. He was buried, and he was raised from the dead on the third day, just as the Scriptures said. He was seen by Peter and then by the Twelve. After that, he was seen by more than 500 of his followers at one time, most of whom are still alive, though some have died. Then he was seen by James and later by all the apostles. Last of all, as though I had been born at the wrong time, I also saw him. For I am the least of all the apostles. In fact, I'm not even worthy to be called an apostle after the way I persecuted God's church."
"And if Christ has not been raised, our preaching is useless and so is your faith. More than that, we are then found to be false witnesses about God, for we have testified about God that he raised Christ from the dead."
"But Christ has indeed been raised from the dead, the first-fruits of those who have fallen asleep."
Are the New Testament sources primary, accurate, unbiased, trustworthy? When were they written? Have they been corrupted or do we read them as they wrote them? How many sources are there inside and outside of the New Testament? Are they independent? Are they coherent?
Here are some people who have tried to address these questions:
Paul Barnett, "Is the New Testament history?" (http://www.amazon.com/New-Testament-History-Paul-Barnett/dp/...)
FF Bruce, "New Testament Documents" (http://www.amazon.com/New-Testament-Documents-They-Reliable/...)
God however may be within the realm of history, if at just the right time, God revealed himself in history. That is the Christian claim: Jesus died and rose from the dead in history.
"And if Christ has not been raised, our preaching is useless and so is your faith. More than that, we are then found to be false witnesses about God, for we have testified about God that he raised Christ from the dead." - Paul the Apostle (a persecutor of the first Christians before seeing the risen Lord for himself, a Roman citizen, highly educated, he was himself martyred for his testimony, after being tried by several of the Roman magistrates, likely including Nero)
To reject the claim of Christ a priori because of naturalistic views of the universe is inadequate.
Better to examine the historicity of the accounts of Christ. How soon after the events were they recorded? What was the cost to those who gave their accounts? Did it happen? If it happened, what does it mean?
Here are some good places to start:
Paul Barnett - http://www.amazon.com/New-Testament-History-Paul-Barnett/dp/... and see also http://www.amazon.com/New-Testament-Reliable-Paul-Barnett/dp...
FF Bruce - http://www.amazon.com/New-Testament-Documents-They-Reliable/...