A decade ago Kirby wrote:
and I continue to maintain that this and Acts is more than sufficient grounds for the presumption of historicity (but not, of course, divinity) simply on the basis of abductive reasoning.But assuming that at least the shorter reference is authentic, what can we conclude from this? It shows that Josephus accepted the historicity of Jesus. Simply by the standard practice of conducting history, a comment from Josephus about a fact of the first century constitutes prima facie evidence for that fact. It ought to be accepted as history unless there is good reason for disputing the fact.