Overview of early Christianity
From a counter-apologetics standpoint, having a basic understanding of early Christianity is invaluable — particularly the origin of the gospels and their historical reliability, as the supposed truth of modern Christianity is more or less completely dependent on these factors. It is very easy to be deeply bogged down in modern metaphysical apologetics by transcendental smoking mirror arguments, and semantic tricks about ontology. Instead, keep in mind where Christianity actually originated. What exactly is Christianity based on? What exactly are Christianity's original claims? Are these claims historically reliable and/or verifiable? If not, everything else that follows is more or less nullified. This page is meant as an overview to tie together the relevant third party articles of greater depth on this fairly large subject.
The Gospels and New Testament
There are 27 books of the New Testament. Starting from the four gospels of Mathew, Mark, Luke, and John, which are usually considered the cornerstone of the new testament, teachings, and life of Jesus. These are followed by a collection of additional books attributed to Paul of Tarsus, Luke the Evangelist, and a number of others.
One of the first things to notice is that the best current historical consensus concludes that the four main Gospels (and indeed several of the other books) were in fact not written by those people commonly attributed to them. The four gospels are all internally anonymous and there are no original signed copies. The names of the four apostles were not attributed to these texts until the late 2nd Century CE, and as late as the 4th Century CE in the case of Mark. The body of the texts themselves were also written many years after the events they claim to report. Mark, the earliest of which, is estimated to be written no sooner than c. 70 CE. A full 40 years after the purported death of and resurrection of Jesus, which more or less precludes any notions the gospels were written by the apostles, or any other first-hand eyewitnesses of Jesus. Furthermore, it is worth noting this is not a fringe belief of a few “atheist extremists”. Even some standardised bibles such as the NIV actually make note of these facts on their relevant title pages.
Synoptic Gospels and Q
The gospels themselves can be divided into two groups: the synoptic gospels of Matthew, Mark, and Luke, and the non-synoptic gospel of John. The word synoptic means “Seen together”, referring to the consistencies of these three books with each other. Upon deeper inspection though, it appears as though the books are not merely consistent, but in fact directly based on each other with large slabs copied word for word, bringing further into question the idea that they would be true eyewitness accounts. Why after all would an eyewitness rely so heavily on a third party account? Originally it was thought that the first book was that of Matthew, but now it is thought that the first book was actually Mark, written no earlier than c. 70 CE. Then from Mark and a second hypothetical document named the Q Document containing a list of quotes supposedly attributed to Jesus or perhaps simply a collection of Greek philosophies such as the Golden Rule, were used for the basis of writing Matthew and Luke between c. 70 and 100 CE.
The gospel of John is Non-Synoptic, quite obviously meaning it is not seen as being together (consistent?) with the other gospels. Its origin is dated later in the 2nd Century CE, and it differs radically in its content and claims from the other three gospels. These inconsistencies range from small details such as the date of the last supper to larger details such as Jesus' performance of miracles, exorcisms, and his stance on old testament Judaic law.
Paul of Tarsus and Luke the Evangelist
Much of the rest of the New Testament is attributed to Paul of Tarsus and Luke the Evangelist. Perhaps more than anyone, Paul is attributed as being the founder of the early Christian church and the propagation of Jesus' teachings. However, by their own accounts, neither Paul nor Luke actually met Jesus face to face. Paul himself claimed that he only saw Jesus in a vision while traveling on the road to Damascus.
The remaining books of the new testament are supposed to have been written by a number of other people including John the Evangelist, Peter, and James the Just. Though as with so many of the other books, the general consensus is that most of these books were not in fact written by those commonly attributed to them.
Perhaps the biggest shortcoming of the New Testament's reliability is that there are absolutely no extra biblical contemporary accounts of Jesus or the extraordinary events of his life. Basically everything we know about Jesus' life, we know from the four gospels. The same four books that make fantastical claims of miracles that completely defy our current understandings of physics, chemistry, biology, history, etc. We can find no third party accounts anywhere to verify or even come close to supporting these claims.
When pressed on the issue, apologists often cite two passages of Josephus, an early Jewish historian, as being extra biblical contemporary evidence of Jesus. Unfortunately for the apologists, Josephus was not born until after the purported life of Jesus and is not a contemporary at all, the passages themselves coming from "Antiquities of the Jews", not published until c. 94 CE, over 60 years after Jesus' death. At best the passages really couldn't tell us much more than what the late first century Christians at the time believed about the Jesus. Furthermore, Josephus was an Orthodox Jew, which is altogether inconsistent with the passages claims that Jesus was the Messiah. Whilst perhaps not being an outright forgery, even decent Christian scholars will admit that the passages were at the very least tampered with probably some time in the 4th century by Christian scribes.
The other major early non Christian historian that apologists often cite is Tacitus, though his testimony fails on many of the same grounds that Josephus' does. He was not born until after Jesus' death, thus he was in no way a contemporary of Jesus. The account cited in Book 15 of the Annals was not published until c. 116 CE, many years after the life of Jesus and in no way a first-hand account. Additionally, the paragraph itself mentions that at this time there was a religious group identifying themselves as Christians, causing problems within the Roman empire, and nothing more. It says little about Jesus or the veracity of the claims surrounding his life and divinity, and even if it did, it would only be reliable so far as telling us that this is what early 2nd Century Christians believed.
Lack of other evidence
Whilst some may make the argument that it's not surprising we don't have a great deal (or any, as the case may be) third party evidence surrounding an itinerant Jewish preacher in a backward corner of the Roman empire, there are additional concerns that further bring the reliability of the gospels into question. The first of these concerns is the supernatural claims of magic and miracles: Jesus bringing Lazarus back from the dead; spontaneously healing the blind; walking on water; spontaneously turning water into wine; precognition; exorcism; death and resurrection; and so forth. Whilst a theist will claim that the miracles are part of Jesus' divinity and consistent in context, we have no reliable documented accounts that such things have ever happened or are even possible within the reality we observe. The claims completely defy our current understanding of physics, chemistry, biology and medical science. In short they are not consistent with reality and further question the nature of the gospels' reliability. The second concern is that the gospels make several grandiose claims that if true should have been documented by third party sources. An example of this is the mass exodus in the Roman empire with everyone having to return to their place of ancestry for an empire-wide census. This is not recorded anywhere outside the gospel of Luke. Another example is towards the end of Matthew, where the dead rise from their graves and walk through the streets of Jerusalem seen by many people. Once again there is no documentation to be found anywhere of this outside the gospel of Matthew. On a geopolitical scale, these were not insignificant events by any stretch of the imagination. If these events were even remotely true we should expect to find at least some third party documentation or record of their happenings in otherwise detailed Roman and Jewish annals. Instead we find nothing.
Further textual corruptions
A further issue surrounding the biblical historical reliability is that there are known forgeries and edits that were added many years after the original writing. Any decent standardised bible such as the NIV will point out that the last few passages of Mark are not in the oldest copies of the manuscripts that we have. They were added some time later in the mid 2nd Century. However these known forgeries are still included in the bible canon and some denominations such as Pentecostal churches largely base their teachings on these known forgeries.
What exactly is Christianity based on?
These claims are based solely on a collection of books in the second half of the Christian bible called the new testament. Specifically the four gospels that claim to provide a first hand account of Jesus' life.
What exactly are Christianity's original claims?
The basis or core original claim of Christianity is that at the start of the 1st Century CE there lived a man named Jesus. Jesus was the divine son of god and performed many spectacular supernatural miracles, good deeds and teachings throughout his life. He was betrayed by one of his own apostles and put to death by the Romans, where his blood sacrifice and resurrection supposedly cleansed humanity of all sin.
Are these claims historically reliable and/or verifiable?
On inspection, the four gospels that provide the core understanding of Jesus' life not only appear to have not been written by the apostles that are attributed to them, but they were misleadingly not written by any first-hand eyewitnesses of Jesus at all. They were all written many years after the purported life of Jesus by people who had never met him. In the case of John, as late as the early 2nd Century CE. The rest of the new testament is made up of parables by people like Paul of Tarsus and Luke the Evangelist, who, by their own admission, never met Jesus during his lifetime and never witnessed the events and miracles claimed in the gospels. As such, even within the context of the bible itself, there is no first-hand account of Jesus' existence. There are no extra-biblical contemporary accounts confirming any of the claims about Jesus in the new testament. The two best examples apologists cite are Josephus and Tacitus who were in fact not contemporaries of Jesus at all, and whose references to Jesus range from the misleading fact that they can really only tell us about what Christians of the time believed about Jesus, and in the case of Josephus, obvious forgery done by later Christian scribes. Furthermore, the Gospels make several grandiose claims of spectacular events, such as the dead rising from the graves and walking through the streets of Jerusalem or 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 to find at least some third party documentation of their happenings in otherwise detailed Roman and Jewish annals. Instead we find nothing. There is no reliable evidence, within or outside of the bible, to support any of the claims about Jesus or the spectacular events of his life.
Epilogue on the historicity of Jesus
It seems clear from the evidence presented in the gospels, new testament books and third party sources, that there is simply not enough evidence to say that Jesus existed as anything more than myth or legend. That's not to say he didn't exist at all though. As the saying goes, “No smoke without fire”. In much the same way that the King Arthur myths may have been based on a real man, it is altogether possible, perhaps even likely, that around this time there was an itinerant rabbi named Yeshua who roamed the countryside preaching and may have even run into some kind of trouble and been put to death by the Romans, but this is pure speculation, and certainly not the Jesus of the new testament who performed many fantastic miracles, healed the sick, walked on water, and was the son of god through death and resurrection. There appears to be no empirical evidence that such a man ever existed.