I do agree with Neil Godfrey that historicists sometimes have a tendency to overlook the circularity that creeps into their arguments. One place where I noticed this was on the question of whether Paul meant to designate a biological or symbolic relationship when he referred to James as "the brother of the Lord." McGrath said of this argument,
If Paul only made vague references to "the brothers of the Lord" of course it might be a viable option to consider it Paul's generic use of "brothers." But Paul's reference to "James the Lord's brother" coupled with the fact that there is no other evidence for "brother" as an honorific title in early Christianity, and later authors either understood it as biological brother or made strenuous attempts to argue it meant "cousin" or "half brother" so as to support the perpetual virginity of Mary, the evidence seems clearly to favor taking it in its straightforward sense.I cannot help but wonder where in early Christianity other than Paul we would be able to look for evidence of the use of "brother" as an honorific. Isn't the conclusion that we have no such evidence based on the assumption that Paul was using "brother" in the biological sense? And if the theory is that Mark historicized Paul's mythological Jesus, can we really refute it with the fact that Mark and later Christians treated James relationship to Jesus' as biological?