I have been very influenced by Harris's idea that the section where Adamantius attacks a Valentinian was originally referencing Marcion. If Harris is right - and I think he is - this section was changed from an attack against Marcion's Antitheses to an anti-Valentinian narrative. Why would the editors have done this? Harris never provides an explanation but I think I have an answer - the text was too sensible. It gave the Marcionite opinions too much air to breathe. It allowed people to 'make sense' of what the Marcionites believed and so - at some later stage - the original treatise was altered to make it seem as if Adamantius took aim at many heretics rather than Megethius the Marcionite.
I found another example of this 'cut and paste' exercise. In the first section an argument which starts with Megethius ends up getting placed in the 'second Marcionite' (= 'Marcus' a Marcionite who follows what we might call the 'classic model' of black and white dualism). We read in the first section of the text Megethius (= MEG) bring up to Adamantius (= AD) in front of the judge Eutropius (EUTR) the four evangelists but only deals with two specifically - i.e. Mark and Luke:
AD. Will you agree if I show from the Gospels that they are not fabrications?
MEG. I will agree if you prove it. First state the names of the Gospel writers.
AD. The disciples of Christ wrote them: John and Matthew; Mark and Luke.
MEG. Christ did not have Mark and Luke as disciples, so you and your party are convicted of producing spurious writings. Why is it that the disciples whose names are recorded in the Gospel did not write, while men who were not disciples did? Who is Luke? Who is Mark? You are therefore convicted of bringing forward names not recorded in the Scriptures.
EUTR. If Christ had disciples, would He not have committed the work to them rather than to men who were not disciples? Something seems wrong here. The disciples themselves ought rather to have been entrusted with the task.
AD. These men are also disciples of Christ.
MEG. Let the Gospel be read, and you will find that their names are not recorded.
EUTR. Let it be read.
AD. The names of the twelve apostles have been read, but not of the seventy-two.
EUTR. How many apostles had Christ ?
AD. First he sent out twelve and, after that, seventy-two to preach the gospel. Therefore, Mark and Luke, who are among the seventy-two, preached the gospel together with Paul the apostle.
MEG: It is impossible that these [two] ever saw Paul.
The argument does not make sense as it stands as Megethius's point is to argue that the Catholic gospels were not written by disciples of Jesus. He only deals with Mark and Luke here. In order to prove his point he has to show that Matthew and John also weren't eyewitnesses.
This line of reasoning now only gets taken up in the second section of the Dialogue, not by Megethius but his 'stand in' Marcus. Indeed the argument as it now stands drops out of the sky as Pretty notes in his translation "The transition is somewhat abrupt. The Latin translator must have felt this, for he makes Megethius say, 'This conclusion (i.e., the judgement of Eutropius) is reached by argumentation, but 1 want to prove what I say from the Gospel writings. But I will first show that the Gospels which you people read are false'. As the above passage down to the words "Gospel writings" is absent from the Greek MSS, Bakhuyzen rightly deletes it as unoriginal. Nevertheless it serves to highlight what was already been said, that the writer of the Dialogue has produced a work which, though valuable as it is in other ways, sometimes suffers from a lack of cohesion as one argument ends and another begins." [p. 41]
This lack of cohesion can best be explained as a deliberate attempt of the editor to not only 'rebaptize' or 'recontextualize' certain key passages (= Harris's claim that parts of the 'Valentinian' section were originally directed against Marcion's Antitheses) but to 'chop them up' and spread them all over different parts of the Dialogue. Notice now for instance that this critical section of part two of De Recta in Deum Fide must originally have followed the last section, even though they are separated by over fifty pages in Petty's translation:
EUTR. How is it, Marcus, that your party do not accept those who were sent out by Christ to preach and proclaim the Gospel, yet you do accept one for whom you offer no proof? Why is it that you disparage Matthew and John, whose names are recorded in Scripture, and whom Christ sent out to preach and proclaim the Gospel, but accept Paul, for whom you have no proof? Surely this is ridiculous? Tell us this at least: Did they proclaim and preach the Gospel or not?
MK. They proclaim the Gospel.
EUTR. Was their proclamation and preaching of the Gospel recorded or unrecorded?
MK. It was unrecorded.
EUTR. It is quite absurd to assert on the one hand that those who were sent out to preach and proclaim the Gospel did so unrecorded, and on the other to claim that Paul, who had not been sent out, taught and was recorded! [p. 91]
In other words, the Marcionite originally made it clear that neither the gospel of Matthew, the gospel of Mark, the gospel of Luke, nor the Gospel of John was written by a disciple of Jesus. It was a wholly spurious composition - an argument whose force is now diminished because the section has been broken up and placed in two different sections of the narrative.