Christianity relies on the authenticity of the New Testament of the Bible as a true, first-hand account of Jesus’ life. Arguments from design and from the creation of the universe are arguments from ignorance (god-of-the-gaps), and don’t prove the Christian god. Rather, they leave us with a vague super-being with any number of unknowable attributes. Miracle stories lack any good evidence beyond that of hearsay and anecdote, and evidence for the supernatural in general has never been verifiable. This leaves only the Bible (specifically the New Testament) as the one thing that Christians can point to as supporting their beliefs.
Before I go on, however, we must make one thing clear. Even if the Bible were a document written by eye-witnesses, that would lend nothing to the truth of those claims. That people merely said it does not make it true. We could drive out to New Mexico and gather stories of U.F.O. abductions from entire communities, families, and individuals, some of which are mysteriously unexplainable and morbidly intriguing, but these people’s words say nothing about the truth of those words. Instead we require real, hard evidence for such claims, not merely stories. Words do not prove themselves. This is the larger point, a reasonable general principle that overshadows the historical unreliability of the Bible that will be later shown.
There is also the reasonable assertion that extraordinary claims require extraordinary evidence. They require extraordinary evidence because the observation of a supernatural entity/event would be highly unusual. Also, proponents often claim that these events violate the known laws of science, making them difficult to square with the way the universe is understood to work. Even a good historical account of a supernatural event would not be good enough evidence of their truth. We would need much more extra support before a rational person could accept them as true.
Moreover, a common apologist claim is that all of written history is from the mouths of people, so we can trust the Bible just like the history books. If that were true, we could equally trust the Quran and the Bhagavad-Gita as true historical accounts. There are differing levels of reliability of historical sources, and in this post I will discuss the unreliability of the New Testament as an authentic source.
The four Gospels are the primary books of the Bible that narrate the life of Jesus. These are the closest thing we have to historical sources about him. He is not mentioned by any contemporary historians, so his life and his miracles are not verified by any third party. But these Gospels, on face value, are not reliable sources. Basic scholarship reveals that these books were not written by the people attributed to them. They are all internally anonymous (they don’t mention the author within the text) and we have no original signed copies. The names of the four apostles were not attributed to the texts until the late 2nd century, and as late as the 4th c. in the case of Mark. Furthermore, they were written many years after the events they describe. Mark, the earliest Gospel, was written no earlier than year 70, a full 40 years after the supposed death and resurrection of Jesus. And the Gospel of John, which differs highly from the other three, was written as late as the early 2nd century.
What furthermore calls the eye-witness nature of the Gospels into question is that Mark, Matthew, and Luke are directly based on each other, with large slabs of text copied word for word. Why would an eye-witness rely so heavily on a third-party account? Inconsistencies between the four Gospels also makes the idea of eye-witness authors less likely. Not counting the inconsistencies between Matthew, Mark, and Luke (such as the differing versions of the empty tomb story) The Gospel of John differs radically in its content and claims from the other gospels, such as the date of the last supper and even larger details such as Jesus’ performance of miracles and his stance on Judaic law.
Much of the rest of the New Testament is attributed to Paul of Tarsus and Luke the Evangelist. However, by their own admission, neither of them had ever met Jesus (but Paul claimed that he saw a vision of Jesus while traveling on the road to Damascus).
A further issue is that there are known forgeries and edits to the text of the Bible that were added for years after the original writing. For instance, the last few passages of Mark are not in the original copy that we have, having been added some time in the mid 2nd century. Some denominations such as the Pentacostal church base their teachings off of these known forgeries. Early copyists of the Bible were often illiterate themselves (most early Christians were from the lower, uneducated class), and could only copy letter-by-letter, greatly increasing the likelihood of error. There are known cases of early Christians intentionally changing the canon in order to more closely align the text with their personal take on the religion. To quote Origen, a 3rd-c. church father, “The difference among the manuscripts have become great, either through negligence of some copyists or through the perverse audacity of others; they either neglect to check over what they have transcribed, or, in the process of checking, they make additions or deletions as they please."
This information is not the view of fringe-atheists. It is widely accepted by Bible scholars, and even some Bibles such as New International Version make notes of some of this on their relevant title pages. The Gospels are not the sort of sources that would be used to make a history book, and would not be accepted in a court of law. They make several grandiose claims such as the dead rising from their graves and walking through the streets of Jerusalem, and a mass exodus in the Roman empire with everyone having to return to their place of ancestry for an empire-wide census. If these events were even remotely true, we should expect some sort of third-party mention of them in the detailed Roman and Jewish annals. Instead we find nothing. There is no reliable evidence, within or outside the Bible, to support any of the claims about Jesus as his spectacular life.