1) the first layer: the original words of Paul the Apostle.
2) the second layer: the interpolations of a Gnostic author (so Loisy) of which the identity, for Turmel, would be the same Marcion.
3) the third layer: the Catholic interpolations/corrections against the second layer.
I see a curious trend: Mythicists of the kind like Doherty/Carrier, of which an example of the past could well be Couchoud, rejected the view of Loisy/Turmel about the matter, insofar this makes of Paul a more "rational" person (as opposed to a mystical/hallucinated person) and accordingly a follower, as the Pillars, of a possibly historical Jesus. Even today, I see that R.G.Price (Mythicist of the kind Carrier/Doherty) disagrees with Roger Parvus about the Loisy's view, fearing probably that a Paul interpolated by a Gnostic author about the his "mystical" parts (to be clear: 1 Cor 2:6-8 and Philippians 2:6-11, in primis) may reduce the utility of the genuine Paul against the possibility of a historical Jesus.
But there is an exception. Prosper Alfaric was a mythicist of the kind Carrier/Doherty but, differently from Couchoud, he accepted the view of Loisy about the interpolations in Paul, preserving the his mythicist views.
I realize that Alfaric wrote the his reasons to remain mythicist (even under the recognition of an interpolated Paul) in the following review of the Loisy's view:
Les Epîtres de Paul, in Bulletin du Cercle Ernest Renan n° 35, april 1956.
My question for the reader: may someone give me the reference to where I can acquire this review? Very thanks for this.