|The Jesus Seminar and the social sciences|
The work of the social-sciences-oriented Context Group has debunked, sometimes unwittingly, many a theory of Skeptic and critic. In Jesus, Justice, and the Reign of God author William Herzog -- who follows the same orientation -- provides a cautious yet damaging analysis of some of the assumptions of the Seminar, as embodied in the comments of Seminar founder Robert Funk.
Herzog tackles several "rules of evidence" that the Seminar uses to determine what words of Jesus were authentic. The criteria examined from Funk are:
Even on the surface it is obvious that many of these criteria are repetitive (1 and 2; 3 through 7); a few are confounded by the nature of oral tradition, and that all of them beg a question. Herzog says as much: "It is obvious that these are less criteria than conclusions about who the historical Jesus was; they are not simply rules of thumb for conducting the search or sorting the evidence. These eight tests reflect Funk's conclusions about Jesus and the gestalt of the historical Jesus he already believes to be true and brings to the task of assessing the evidence." 
Before any critics start using ad hominems, Herzog, we must note, is no fundamentaliste but a professor of NT Interpretation at Colgate Divinity School. His view of the resurrection is not orthodox and he has no axe to grind for Jesus -- other than one properly viewed in his own context.
Herzog finds Funk's criteria, initially, often self-contradictory: "If Jesus' talk was memorable and distinctive but without 'explicit application,' then how can he know it was characteristic of Jesus to call for a 'reversal of roles' or that he frustrated 'ordinary, everyday expectations'? Both role reversals and frustration of expectations are 'explicit applications' of Jesus' talk. And if Jesus indulged in parable for parable's sake and metaphors for metaphor's sake, then how can Funk know that his sayings and parables 'cut against the social and religious grain,' since this too is an application of Jesus' teaching? Indeed, if we are to take Funk's eight tests at face value, we would conclude that Jesus taught vividly about nothing of social, politicial, or economic consequence."
Herzog also notes that parables are hardly "short". The criteria are internally self-contradictory, which clearly points to a begged question -- not a careful construction.
Beyond this, Herzog then shows that these criteria are "even more problematic when placed in the context of a traditional agrarian society." Herzog notes that Funk's criteria that refer to Jesus' teachings as "distinctive" and radical undercuts any idea that Jesus could have ever gained any recognition: "An inidividual and distinctive voice was not valued [in Jesus' world] and would have been little heeded. What contemporary scholars scorn as 'conventional wisdom' is what first-century Galileans would have prized far above a deviant individualistic voice." 
Essentially the Seminar's tendency to "blacklist" any saying that reflects "conventional wisdom" and to claim that it was put in Jesus' mouth is worthless. Mouthfuls of conventional wisdom was a route to success and attention; being a "Cynic sage" or a deviant was not. Herzog concludes: "To conform Jesus to a familiar, modern mold may yield a Jesus comfortable to some inquirers but fails to account for the historical Jesus of Galilee and Judea."  This Jesus would be, in context, a nobody, incapable of founding a movement or gathering disciples, especially Galileean ones.
Under this rubric as well, a well-worn criterion even used outside the Seminar -- the so-called "criterion of dissimiliarity" (words of Jesus may be regarded as authentic if they do not reflect sayings or needs of Judaism or the early church; i.e., the Golden Rule vs. Hillel's words) -- becomes an anachronism. Any criteria that removes Jesus from his context -- whether it be a Cynic sage model, or any politically-correct idea of a radical teacher for his time -- falls and breaks on the rock of the social sciences.