I have discussed the first two principles in two earlier posts. The criterion of coherence, the third principle, is also famously used to achieve the Jesus Seminar Jesus. Once we run the Jesus traditions through the dissimilarity principle and determine that it meets this requirement, and we have noted whether or not the material is multiply and independently attested (the more independent attestations the better), we have identified a small block of material as Jesus'. What do we do with the rest?
Rather than cast it aside, we rummage through it again to see if we might pluck out anything else to fatten up the little heap of words we were able to reap fishing with the dissimilarity principle. In Norman Perrin's words, "once characteristics of the teaching of Jesus are established [by satisfying the dissimilarity principle], these characteristics can be used to validate sayings which themselves would not meet the requirements of the criterion of dissimilarity...What we are proposing, in effect, is to use material established as authentic by the one sure criterion as a touchstone by means of which to judge material which itself would resist the application of that criterion, material which could not be established as dissimilar to emphases of Judaism or the early Church" (Rediscovering the Teaching of Jesus, p. 43, 45).
Now this criterion makes some sense to me, as long as the "one sure criterion" that you are using previously is really "sure." But in the case of the dissimilarity criterion, the only thing "sure" about the results is that we have identified some material that the early Christian authors found useful enough to preserve, and were not at all certain that this material originated from Jesus or even reflected his historical teachings. So to use a criterion like this, we would need to be very cautious that the material already identified was as definitive as we are going to get, and then we would have to make judgments about what "other" material we thought cohered. Are we going to choose material that coheres to the Jesus we desire to create, while ignoring the other material? It is very risky, and safeguards would need to be established in order to counteract this possibility, safeguards that I don't see in place in the construction of the Jesus Seminar Jesus even though the general rule for the Seminar was "Beware of finding a Jesus entirely congenial to you" (Funk, The Five Gospels, p. 5).
In fact, it seems to me that the Seminar did have a picture of Jesus that they assumed from their work with the dissimilarity principle, and which affected their authenticity decisions of other sayings, allowing them to present a Jesus entirely detached from history:
1. "Jesus' characteristic talk was distinctive - it can usually be distinguished from common lore" (Funk, p. 30).The criterion of coherence is only going to be as good as the original data set and the controls put on it by the scholar. It will reveal material that is "like" the original data set, but tells us nothing about whether or not Jesus spoke the material. It might begin to give us insight into clusters of "like" traditions though, which might help us to locate the material within the tradition history of early Christianity.
2. "Jesus' sayings and parables cut against the social and religious grain" (Funk, p. 31).
3. "Jesus' sayings and parables surprise and shock: they characteristically call for a reversal of roles or frustrate ordinary, everyday expectations" (Funk, p. 31).
4. "Jesus' sayings and parables are often characterized by exaggeration, humor, and paradox" (Funk, p. 31).
5. "Jesus' images are concrete and vivid, his sayings and parables customarily metaphorical and without explicit application" (Funk, p. 32).