"It is a habit of mankind ... to use sovereign reason to thrust aside what they do not fancy." - Thucydides

I think this is true about Jesus Christ too, those who deny or denounce Him claim they use "sovereign reason" to do so. "Fancy" in this instance means "to believe without being absolutely sure or certain." I truly feel both people who believe and don't believe both do so without being absolutely sure or certain. Some atheist argue against the Historicity of Jesus Christ because there isn't sufficient evidence to their liking (and also use a type confirmation bias to get their point across), and similarly most Christians understand there isn't that definitive physical evidence that would satisfy the most ardent skeptic to prove His existence once and for all.

Since archaeologist use things dug up from the dirt like weapons, jewelry, clothing, bones and other other artifacts to confirm a person existence from the past so I guess the Jesus deniers uses that lack of evidence (that Jesus Christ had no archaeological artifact attribute to Him) as basis for their argument against the historicity of Jesus. While the person who believes Jesus lived uses Confirmation bias ["Confirmation bias is a tendency for people to favor information that confirms their preconceptions or hypotheses regardless of whether the information is true."] The Jesus denier does the opposite they use the lack of information to confirms their preconceptions or hypotheses regardless of whether their particular stance is true or not. I guess you can say they use "negative confirmation bias."

nope Muslims consider him a "human" prophet who died on the cross

the God who came back after death was an impostor and his ascension were all lies, according to my Muslim friends

-No external reliable sources mention him.
-Josephus (born after Jesus was supposedly killed) mentions him after telling about the atrocities of Pilate, but the text style is so out of context, that it suggests that it was for some reason forged at later time by a Christian. Had Josephus actually thought Jesus was divine, like the passage suggest, surely he would have written a lot more about him, than one paragraph. Instead Josephus mentions over 20 other Jesuses, (it was a common name) and writes in length about them and other people.
-Talmud mentions executing several Jesuses, but they are executed by stoning or hanging
-Books in the Bible mention him, but they tell conflicting stories.
-It is possible that none of the books in the Bible were written by an eyewitness
-Paul only saw him in a vision, yet he wrote large part of earliest books in the bible
-Very large parts of the Gospels are clearly fictional, added there just to make the story convincing, and to make it match the prophecies in OT
-The whole idea of suffering savior was 500 years old prophecy from Isaiah 53
-The Gospels were written after or during the Roman Jewish war 66-70 AD, and destruction of Jerusalem and the Temple. During the Titus's siege of Jerusalam in 70 CE, Roman soldiers crucified up some 3,600 Jews over the course of several months... up to 500 in a single day. So many Jews were crucified outside of the walls that "there was not enough room for the crosses and not enough crosses for the bodies".
-As so many sacrificed their lives on crosses to save Jerusalem, the Gospels might actually be telling an allegorical story.
-The Bible was collected slowly over following centuries. None of the original texts have survived, only copies of copies of copies, several decades or centuries after the originals
-We don't know how much the texts were modified or censored.
-We do know that thousands of people called Jesus (Yeshua) existed, some of them were executed, thousands of people were crucified, and several Christ claimants existed.

So it is entirely possible that Biblical Jesus was one of them, but the story may have been wildly different. Such common ingredients in the story make it also possible that the first author might have used the common themes to create a story. So were the books of NT based on the old myths and prophecies, decorated with themes from that time period, or were they based on a historical person, and decorated with old myths? So much of the stories are mythical, filling prophecies, allegorical, and based on visions+personal opinions, and stories heard from others, that I find it difficult to be convinced either way.

Negative confirmation bias would simply be a confirmation bias. It would be the equivalent of a preconcieved notion that a hypothesis is false rather than the hypothesis being true.

I think what you are thinking of is better called something like "truth criteria". People who think like me want things about our universe that they believe to be "true" to fulfill certain criteria, for example that it is proven through hypothesis testing. I like the principle of parsimony which is often called occam's razor although most people who use that word don't fully understand or appreciate what it is. It is a criteria by which you can evaluate hypotheses. If you have two hypotheses explaining a phenomenon, the one which requires you to make fewer new assumptions about our universe is the preferred one.

If you don't know how to put this philosophy to daily use, here's an example I've used before. Imagine you are in a dark house at night - a door closes behind you, but there is noone there. You have two hypotheses to explain the door closing - either it was a draft or it was closed with intent by a ghost. Accepting that it was a draft only requires the assumption that a draft could get into the building - we already know moving wind can close doors, something that can be explained by physics and observed through daily experience .. Accepting that the door was closed by a ghost, however, may require you to accept assumptions like there is a "life" after death, dead people are able to interact with our environment by closing doors, will and intent can exist without a hard physical body etc. etc.

Every time you make a new assumption, there is a chance that the assumption is, in fact, wrong. So, when piecing how the world functions together by testing hypothesis after hypothesis, parsimony as a criteria helps us find the truth by reducing the risk that we will accept a lie as being true. People who want their beliefs to match how the universe actually is should try to follow it I think. Broadly speaking, that's what sceptics do.

There's a lack of Jesus evidence so if you believe he really existed, there is a fair chance you're believing in a lie. Sceptics don't like to take that risk.

It is not the lack of evidence that makes me not believe in the existence of Jesus Christ, or his divinity, or the existence of a god at all. It is just one more nail in the coffin for me.

1) If Jesus of Nazareth had been invented, he would probably never have been called Jesus of Nazareth. The Messiah was supposed to be from Bethlehem. Luke tried to write a retcon, to show that he was actually born in Bethlehem do to a very convenient counting of people, but that never happened.

2) If Jesus of Nazareth had been invented, the accounts of his life probably wouldn't differ as much as they do. Invented stories tend to have their details straightened out earlier than those messy, contradictory eyewitness accounts.

3) "There's a lack of Jesus evidence so if you believe he really existed, there is a fair chance you're believing in a lie. Sceptics don't like to take that risk."

This is kinda wrong. For a simple executed Jew from 2000 years ago, there is an overwhelming amount of evidence. Relatively speaking. Those times really aren't that well documented, especially backwater areas like Judea, especially non-important people like a carpenter with somewhat radical ideas.

It sounds like you're assuming that, if Jesus was invented, he was created whole cloth by a single author. I don't think anyone is suggesting that. He would have had countless authors and evolved out of an oral tradition just like any other mythological figure.

This is completely untrue. It's part of the nature of folklore to evolve over time and vary from teller to teller. The urban legend of the vanishing hitchhiker is an excellent example of this.

This argument makes no sense. So he's relatively described more than the average carpenter of his day and age. How does that improve the quality of the supposed evidence?

Pfft... that's bull****. Everyone knows the vanishing hitchhiker is Rutger Hauer.

lol