Also important are the sources we don’t have. There are no existing eyewitness or contemporary accounts of Jesus. All we have are later descriptions of Jesus’ life events by non-eyewitnesses, most of whom are obviously biased. Little can be gleaned from the few non-Biblical and non-Christian sources, with only Roman scholar Josephus and historian Tacitus having any reasonable claim to be writing about Jesus within 100 years of his life. And even those sparse accounts are shrouded in controversy, with disagreements over what parts have obviously been changed by Christian scribes (the manuscripts were preserved by Christians), the fact that both these authors were born after Jesus died (they would thus have probably received this information from Christians), and the oddity that centuries go by before Christian apologists start referencing them.
Agnosticism over the matter is already seemingly appropriate, and support for this position comes from independent historian Richard Carrier’s recent defense of another theory — namely, that the belief in Jesus started as the belief in a purely celestial being (who was killed by demons in an upper realm), who became historicized over time. To summarize Carrier’s 800-page tome, this theory and the traditional theory – that Jesus was a historical figure who became mythicized over time – both align well with the Gospels, which are later mixtures of obvious myth and what at least sounds historical.