I was reading an article this morning by Daniel Wallace about the ippissma vox (the voice of Jesus) vs. the ipissima verba (the very words of Jesus). The distinction is this the vox is the meaning of Jesus's teaching. So if we were recounting a speech we both heard, but use differing words with the same meaning we would be getting at the "vox" or voice of the speaker. If we had a transcript of the speech we would have the verba of the speech or the very words.
In the paper Wallace made much of the differences in the gospels, and how the authors may have taken some liberties with what they wrote to promote various theological points. One example he gives is that of the rich young ruler. I took a screen shot of the relevant section:
The difference Wallace points out here is that in Mark it seems that Jesus is pressing the rich young ruler to think about his identity. The young man calls Jesus "good teacher" and Jesus asks, "why do you call me good? No one is good by God alone." This is obviously Jesus' attempting to get the young man to reflect on his identity as Israel's divine messiah. Wallace then looks at the parallel in Matthew and argues that Matthew was uncomfortable with Mark's inductive christology because it left open the possibility that people would get it wrong. Matthew rephrases it as: "Then someone came to him and said, "Teacher, what good thing must I do to gain eternal life?" "Why do you ask me about what is good? Only one is good."
Clearly there is a difference, but do these differences mean that Matthew has Mark in front of him copying it and changing things? And NT scholars argue this for all similarities in the Synoptics and I find these arguments to be suggestive, but I think the similarities and differences can be explained in another way. If Matthew is written by an apostle and Mark is written as the memoirs of Peter, as church tradition had held from the earliest days, we may be looking at something much more common.
What is this much more common thing that I have in mind? Simply this, in-group retelling of stories. An example: my grandfather died a few years ago and my family has stories we all cherish about him. The level of similarity between us on the stories is bewildering. There are important events in every person's life, and when people are around they become the things that are remembered. Humor, acts of kindness, and other character traits are also remembered. We often have differing accounts of the words my grandfather, but we also agree on what those events meant, and what he meant. If we can do this with my grandfather who was not an itinerant preacher, then how much more would the gospel writers have remembered about Jesus? Probably quite a bit. And they would have talked to one another about these things. And if the suggestion that they took notes is realistic we may have an explanation of the similarities and differences in the gospels without appealing to hypothetical gospels. It simply could have been individual notes, and stories that they told one another around the camp fire about their memory of Jesus.
This explains the synoptic gospels, but what about John? It seems to me that John, getting on late in life, had knowledge of the first three gospels and felt the need to supplement them with some of Jesus' other teachings and actions. This would explain some of the undesigned coincidences we see between John and the synoptics. If John was making stuff up out of the whole cloth we wouldn't have these similarities and elucidations between John and the synoptics. Maybe he heard some things better than other disciples, maybe he was there at differing confrontations and left an account of them for us ( I am not sure about that suggestion, I will have to read John with that in mind).