This is intended to be a very short article addressed to those who claim that the New Testament is evidence that Jesus of Nazareth existed and performed miracles.
Essentially, insofar as the Gospels go, we have 4 writers who talk about the life of a man who apparently lived 2000 years ago. There are also some letters written about this man. Most are written by Paul who himself has never known a physical Jesus (he allegedly appeared to Paul in visions). There are also a number of letters written by other people. Scholars are constantly in dispute about the authorship of most of these letters as well as about the authorship, dating, chronology and reliability of the four gospels.
Here's what I think on all this:
1. The Gospel stories are often at odds with each other. They seem to see this man in very different perspectives, and often giving inconsistent accounts about purportedly factual events.
2. These four versions also contradict known history (Matthew has the nativity scene during the life of Herod the Great who died in 4 BC while Luke has it during the reign of Quirinnius who became governor of Syria in 6 CE. There's no mention of Herod's slaughter of innocents outside of Matthew, despite there being much said by contemporary historians about Herod's cruel crimes IN DETAIL. There are many more examples).
3. Those who study these accounts can't seem to agree on who wrote them, when they were written, how much of them is true, how much was copied from each other. There are disagreements among non-Christian scholars (ranging from disputing Jesus' very existence to disputing any number of specific claims about his life and death) as well as between Christian and non-Christian scholars, as well as between Christian scholars and other Christian scholars.
4. Even as early as the very first century, there were a number of interpretations of all this, with people having very divergent beliefs about what actually happened and what it all means. This is why Paul has written his epistles, strenuously trying to set all the various churches straight, to give them a consistent message. We know that there were a number of early Christian sects, with a range of beliefs and that this wasn't streamlined until much later in the piece, when Christianity was finally embraced by the State.
5. Apart from the canonical gospels (the four that we have in our New Testament now), there have been a number of other accounts written and rejected by the early Church. This selection took place many years after the purported death of Jesus and the earliest mention of the four gospels that we have now is by Irenaeus, at the end of the 2nd century CE. These non-canonical gospels are visibly embellished (Peter's Gospel, for instance, speaks of a talking cross, and of Jesus' face stretching all the way up to the sky). Since it is common ground that early Christians were capable of embellishing accounts (no criticism of them, it's very much human nature to do so), how can we possibly claim that there were no embellishments in the four canonical gospels? Many scholars agree that Mark (the simplest and least fantastically-sounding gospel) was the first, with the three others following, copying (at least in the case of Luke and Matthew) large portions of Mark. The answer is we can't. We would expect them to be LESS embellished than later gospels (as there was less time for the legend to become more fantastic) and that's what we do see. But the mere fact that they're not AS embellished as those later ones, doesn't mean they themselves were not embellished. The tendency to embellish religious accounts is there; it's on record. And indeed, scholars (again, of all breeds and faiths, including those faithless ones) can't seem to agree on how much of these gospels was embellished. This includes many Christian scholars agree that some of it was (the days of claims of scriptural inerracy in scholarship are long gone).
In essence, you have four authors of disputed origin, whom we can't say anything about with any degree of certainty, claiming that a guy existed and did miracles.
Question: What's more likely in these circumstances? That the guy really walked on water and changed water into wine or that we're confronted with yet another legend? To be sure, there's no shortage of pious legends about miracles in ALL religions. As recently as the late 20th century, we've heard "eyewitness accounts" about Charles Manson levitating a bus.
I think the answer is clear: it's way more likely that the writers were either lying or mistaken (perhaps by the legendary sources they relied on) than that a man has walked on water. Guys just don't walk on water. If you want to claim that such a thing has really happened, you better have some very, very compelling evidence. And clearly, as dubious (and subject to so much disagreement, even between devoted EXPERTS, including those who ARE Christians) an evidentiary base as what we have here is insufficient to make any claim that these miracles really took place.
With all this in mind, if you think the New Testament is evidence that Jesus existed and performed miracles, your position effectively amounts to "it must be true because somebody at some time wrote it". Sorry, no cake.