Arguments for ahistoricity:
Leadups for Plausibility/Excuses:
There is no certain evidence of a mention of Jesus in any account not influenced by the Gospel tradition (which originated, at latest, c. 70 AD). Tacitus, writing some years after that date, may well have been influenced by the historicist tradition.
The use of the Septuagint to write the life of Jesus, even in Mark.
The ‘silence of Paul‘.
The reliance of visions in Paul’s narration of the life of Jesus (Galatians 1:11, 1 Cor 11:23).
Arguments for historicity:
Paul seems to view Jesus as temporarily being an earthly character.