Using Occam’s Razor I would say the theory to go with is that Jesus was “made up*”. For all religions that have come about in more recent times (for example Mormonism and Scientology) that we have actual contemporary documents for how they came about (personal and 3rd party contemporary accounts and so on) we know religions are simply made up. To suppose Christianity was an exception to this is to unnecessarily add additional elements to the theory, in other words we would be saying “religions are made up except for Christianity”.
*By made up I am meaning the claimed foundational events are made up, so there are no “clears”, there are no solid gold tablets, no Angels appeared and so on.
There is a light-year of distance between the religion being made up and the
founder being made up. We know that Mormonism was founded by Joseph Smith and Scientology has L. Ron Hubbard as a flounderer.
As a general rule of thumb if a religion proclaims a human founder it has turned out that founder existed. Sure, you have maybes like Siddhartha Gautama (Buddha) but they tend to be rare.
Even the John Furm cult can point to a possible founder - Manehevi - the first native history records using the name "John Frum". Though admittedly there
may have been an lost founder who started things up in the 1910s but only one letter even shows he may have existed.
Jesus is unique in that the evidence for him being a historical myth with single person behind it is next to nil. Also when compared to about any other founder Jesus is a total train wreck in terms of history (Pontius Pilate's behavior is totally at odds with what we know of him through every other source) It certainly doesn't help that there are these strange gaps in the records of people who recorded events of that time.
For example, the five volume account (c40 CE) regarding his embassy to Caligula that he wrote is missing the entire volume regarding Pontius Pilate.
Some other missing/strange omission works:
*Damis, author of Apollonius of Tyana, a philosopher and mystic who was a contemporary with Jesus.
*Seneca the Younger's
On Superstition (c.40 - c.62), which covered every cult in Rome, was not preserved. The only reason we know it did NOT talk about Christianity at all is because Augustine in the 4th century complained about it. But if the book could have been as early as 40 CE then there would be no reason to expect notice of what at that time would have been a very small group. Despite this, Seneca's lack of mention was sufficiently troublesome to some early Christians that they forged correspondence between Seneca and Paul of Tarsus. Jerome, in de Viris Illustribus 12, and Augustine, in Epistle 153.4 ad Macedonium, both refer to the forged communication.
*Pliny the Elder, who wrote
Natural History (77 CE), the oldest known encyclopedia. It has 37 chapters, spread over 10 books, and mentions hundreds of people (major and minor characters alike) - and yet, it contains no reference to either Christ or Christians. Pliny the Elder also wrote a history of Rome, from 31 CE to the then-present day (sometime before his death in 79 CE) with a volume for each year. This work, however, was not preserved by the Christians.
*Celsius'
The True Logos (2nd-century) is known only through Origen's rebuttal in the 3rd century.
*Froto, a 2nd century teacher, friend, and correspondence to Emperor Marcus Aurelius (121-180), wrote 'Discourse against the Christians' which is only known through Minucius Felix's Octavius rebuttal of the 3rd century.
*Juvenal, Martial, Petronius, and Persius, Roman satirists who favored topics similar to Jesus's story.
*Cassius Dio's Roman History has the sections covering 6 to 2 BC and 30 CE missing.
*Pausanias, whose massive Guide to Greece includes mentions of thousands of names, including minor Jewish figures in Palestine.
*Historians Epictetus and Aelius Aristides, who both recorded events and people in Palestine.
*Clovius Rufus' detailed history of Nero, which would have documented the active persecution of Christians by Nero, was not preserved.
*Tacitus: the entire section covering 29-31 CE of the Annals: “That the cut is so precise and covers precisely those two years is too improbable to posit as a chance coincidence.” (Carrier)
*Papias (2nd century): Five volume
Explanations of the Stories of the Lord (c 130 - c 150) which is known only through all too brief references and quotes. And what we do have makes him come off as very gullible and that he knew of the apostles only via people who had claimed that they knew them.
*Hegesippus: Five volume
Memoirs (c 180) that covered various legends about the early churches and apostles as well as a list of the first bishops. As with Papias known only through all too brief references but enough to show that any actual history had been replaced by myth and legend.
You would have to be blind not to see the
pattern here.