Just read Chris Keith “Memory and Authenticity: Jesus Tradition and What Really Happened,” ZNW 102 (2011), 155-77, have to mention this amusing quote:
[F]rom the perspective of social memory theory, scholars in search of authentic Jesus traditions might as well be in search of unicorns, the lost city of Atlantis, and the pot of gold at the end of the rainbow. Not only are there no longer Jesus traditions that reflect solely the actual past, there never were. All tradition – all memory – is an indissoluble mix of past and the present. The present would have nothing to remember if it were not for the past; the past would not be capable of being remembered if it were not for the frameworks of the present.