Another argument offered for the traditional authorship of the canonical gospels is that the communities for which the gospels were written would have known who wrote them and would have passed that information along, i.e., even though Mark didn’t attach his name to his gospel, Mark’s community knew that he had written it and would have passed along that information when copies were made. According to this reasoning, when Irenaeous finally identified the authors in 180 A.D., he was simply recording information that had been known all along.
The problem with this argument is that it assumes its conclusion. It assumes that the authors of the gospels were prominent people whose names would be associated with the gospels. What seems just as likely is that the earliest gospels were the product of ordinary nameless Christians who just happened to have sufficient literary skill to compose a coherent narrative from the stories that were known in the oral tradition of their communities. The believers within each community might have known the identity of the writer, but they would not have viewed him as being the source of the stories. The source of the stories was the oral tradition that had come down to the writer.
Most beginning guitar books contain old folk songs like “Go Tell Aunt Rhody” that are listed as “writer unknown.” There must have been someone who first wrote down the words and lyrics and there might even be some musicologist somewhere who knows his name. However, it doesn’t stay with the song. To the overwhelming majority of people who try to learn to pick out the notes, that name is meaningless.
If an early second century Christian from Corinth were to bring back a copy of an account of Jesus’ life that he had obtained in Ephesus, he would probably describe it as the story that the Ephesians knew about Jesus. Even if the Ephesians told him who had written it down, the Corinthians wouldn’t have any reason to remember the writer’s name or to pass it along unless that person had some notoriety that extended beyond Ephesus. This would explain why the gospels circulated anonymously for decades until theological disputes with the Marcionites and other heretics made it important to establish the authority of the orthodox writings by associating them with an apostolic source.