The main point I would make in response is that, without writing being involved, the entire notion of a precise verbatim repetition of a story is meaningless. It may be that with some sayings, plays on words were central, and thus we can be fairly certain that such details were preserved (e.g. straining out a gnat and swallowing a camel). But unlike a book read over and over to a child, a story which Jesus composed and told more than once would be subject to the same limitations of memory to reproduce material verbatim that would subsequently affect the retelling by others. Anyone who has written something – even a poem or song in which melody, meter, rhyme, and other features aid recollection – will know that having written something yourself is not a guarantee that you will remember it.
In addition, having been quite pessimistic about our ability to prove the authenticity of any Jesus tradition or to have the actual words of Jesus, both here and on Michael Kok’s blog, I want to note a counter-argument. Anyone who has read to a small, preliterate child will recognise the speed with which they are able to learn by heart the text of a favourite book. Any attempt to alter the words or skip pages is met with loud protests and some will also offer to ‘read’ the book to you, sitting down and leafing through the pages, turning at the right time whilst reciting the words for you. I suspect that some of Jesus’ teachings were produced often enough so the disciples who travelled around with him got to know them pretty much by heart. I still think that the time-lapse between when Jesus taught and the gospels were written down, combined with the vagaries of both individual and social memory mitigates against our being able to prove that the gospels contain Jesus’ actual words, but I don’t think that what we have is necessarily a long way removed from them.
On a related note, the sad news that Birger Gerhardsson passed away has been circulating, including on The Jesus Blog. Gerhardsson’s work focused on rabbinic teaching using memorization, and so is also obviously relevant to this subject. The Eerdmans Blog lists a number of other scholars who passed away this year.
See too Mike Kok’s several recent posts on topics such as whether social memory has replaced form and redaction criticism.
Finally, let me share share a video that Gavin at Otagosh shared a while back, presenting four views on the historical Jesus: