to MrMacSon,
What is the probability that the James killed in the 60s in Jerusalem, in the accounts of Clement, Hegesippus, and Josephus, are all the same James?
What is the probability that Josephus, as a Jewish military leader, would have come in to contact with a James the leader of a sectarian group?
What is the probability that, if Josephus knew such a sectarian-leader James, he was the one whose death was described by a/ Josephus himself, or either b/ Clement, or c/ Hegesippus, or d/ 2 or 3 of those authors?
I give a probability of 20% for all that, this 20% mostly for the possibility of being an interpolation.
For point 2, Josephus was not yet a military leader in 62 AD. Furthermore, he did not have to get in contact with James to know about his brother, as I explained before.
For point 3, Josephus was much closer (in time and location) of James at the times of his death than Hegesippus and Clement of Alexandria.
Separately, 1 what is the Probability that there was a James who was the blood brother of Jesus?
2 Which James in the Synoptics might he have been?
3 What is the Probability each of the James in the Synoptics was Jesus blood brother?
4 Was the same James in Gal 1:19 the same James as in Gal 2? What is the Probability they are the same?
5 Which James was in 1 Corinthians 15:4-8? (NRSV)
4 ..he was buried, and that he was raised on the third day in accordance with the scriptures, 5 and that he appeared to Cephas, then to the twelve. 6 Then he appeared to more than five hundred brothers [and sisters] at one time, most of whom are still alive, though some have died/fallen asleep. 7 Then he appeared to James, then to all the apostles. 8 Last of all, as to one untimely born, he appeared also to me.
6 What is the probability that that James was the same as the other James?
7 Separately, again, What is the probability that a James became the leader of the early church? ahead of Peter?
8 What is the probability that James was Jesus biological brother?
Now we are talking about the probability of the existence of James, the blood brother of Jesus. That's a different matter.
For points 1 & 8, according to Josephus (80%) and Galatians (90%) (with some confirmation from gMark), I would calculate P = 1 - [(1 - 0.8) * (1 - 0.9)] = 98%
For your points 2 & 3, I already stated that not all the "James" in the Synoptics are about James, the blood brother of Jesus.
For point 4, the probability is very high because no other "James" are mentioned in the epistle. So the "James" in Gal 2 has to be the "James" of Gal 1:19.
For point 5 & 6, this is part of an interpolation
http://historical-jesus.info/9.html. But I think the interpolator was thinking about James, the brother of Jesus, because he was the most important "James" according to Galatians and Acts.
For point 7, according to my study, Peter was the first leader of the Church of Jerusalem after the Greeks' dispersion (around 35) but got progressively supplanted by James, the brother of Jesus.
Cordially, Bernard